JP2001015156A - Nonaqueous electrolyte battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To made nonauqeous solvent used for nonaqueous electrolyte nonflammable and to improve the cycle characteristic of a battery by including phosphate compound or radical polymerization inhibitor in the nonaqueous electrolyte. SOLUTION: Phosphate compound contained in nonaqueous electrolyte is expressed by formula I. In the formula I, R1-R4 are a substituted or non- substituted cyclic aromatic group; and is a substituted or non-substituted cyclic aromatic group or heterocycle. Preferably, R1-R4 are each a phenyl group, a benzyl group, etc., and A is an ortho, meta, or para position substituted phenyl group, substituted biphenyl group, or bisphenol A. A phenotiazine compound expressed by formula II is preferable for the radial polymerization inhibitor contained in the nonaqueous electrolyte. In formula II, R5-R7 are each hydrogen atom, a substituted or non-substituted straight chain or branch alkyl group, etc., and X is absent or 1-2 (integer) oxygen atoms.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a positive electrode, a negative electrode,
And a non-aqueous electrolyte battery including the non-aqueous electrolyte.

[0002]

2. Description of the Related Art In recent years, many portable electronic devices such as a camera-integrated video tape recorder, a mobile phone, and a portable computer have appeared and their size and weight have been reduced. Researches have been made to improve the energy density of batteries that are portable power sources for these electronic devices, particularly secondary batteries. Among secondary batteries, lithium-ion batteries are expected to have higher energy density than lead batteries and nickel-cadmium batteries, which are secondary batteries using conventional aqueous electrolytes. It is being advanced.

[0003] Non-aqueous electrolytes used for lithium batteries or lithium ion batteries include carbonate-based non-aqueous solvents such as propylene carbonate and diethyl carbonate, and Li
A solution in which PF ₆ is dissolved is widely used because it has relatively high conductivity and is stable in potential. Among batteries using these nonaqueous electrolytes, lithium ion secondary batteries are known to have higher safety than batteries using metallic lithium.

[0004]

[Problems to be solved by the invention] However,
When considering a significant increase in the energy density and an increase in the size of a battery, it is considered that a technology for further improving safety is important. The electrolyte used here is a non-aqueous type, that is, an organic solvent type, and is flammable. Therefore, it is almost impossible for the electrolyte to leak from the battery. However, considering the case where the electrolyte leaks for some reason, it is more preferable that the electrolyte is flame-retardant.

[0005] Therefore, it has been proposed to include a phosphate compound in a non-aqueous solvent in order to make the electrolyte solution nonflammable. However, despite the fact that phosphate ester compounds are relatively stable electrochemically, the oxidizing and reducing power of the material used for the positive electrode or negative electrode is very strong,
The phosphoric ester compound reacts with the material used for the positive electrode or the negative electrode. The reaction product of this reaction grows as a film on the electrode surface, and this film increases the impedance of the battery. As a result, there is a problem that the voltage drop becomes large particularly when the battery is discharged with a large current, and the cycle characteristics deteriorate. In particular, when the content of the phosphate compound in the non-aqueous solvent is 30% by weight or more, there is a problem that the deterioration of the cycle characteristics becomes large.

[0006] The above lithium ion secondary battery is
At the end of charging or overcharging when the positive electrode has a high potential, the solvent of the non-aqueous electrolyte decomposes, and its decomposition products (polymers, etc.) adhere to the electrode, resulting in an increase in internal impedance after storage. Thus, there is a problem that the discharge characteristics are reduced and the charge / discharge cycle is further reduced.

In order to suppress the decomposition of the above-mentioned solvent and improve storage characteristics and charge / discharge cycle characteristics, for example, a part of hydrogen atoms of a cyclic ether such as tetrahydrofuran and 1,3-dioxolane is replaced by an alkyl group or the like. Attempts have been made to substitute and stabilize as 2-methyltetrahydrofuran, 4-methyl-1,3-dioxolane, etc. (JL
Goldman, RMMank, JH Young and VRKoch: J. Electroc
hem. Soc., 127, p1461 (1980)).

Further, Japanese Patent Application Laid-Open No. 7-320779 proposes to add a sulfide compound such as methylphenyl sulfide, diphenyl sulfide or chantrene to an electrolytic solution in order to suppress the decomposition of a solvent. However, under the high temperature storage condition, the effect of suppressing the current state is not sufficiently obtained.

SUMMARY OF THE INVENTION The present invention has been proposed in view of the above-mentioned conventional circumstances, and has been proposed in which a non-aqueous solvent used in a non-aqueous electrolyte is made flame-retardant and the cycle characteristics of a battery are improved. An object is to provide an electrolyte battery.

[0010]

A non-aqueous electrolyte battery according to the present invention comprises a positive electrode having a positive electrode active material, a negative electrode having a negative electrode active material disposed opposite to the positive electrode, and a positive electrode having the negative electrode active material. And a non-aqueous electrolyte interposed therebetween, wherein the non-aqueous electrolyte contains a phosphate ester compound represented by the general formula (1) or a radical polymerization inhibitor.

[0011]

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(In the formula, R _{1 to} R ₄ represent a substituted or unsubstituted cyclic aromatic group, and A represents a substituted or unsubstituted cyclic aromatic group or a heterocyclic ring.) The present invention as described above. In the non-aqueous electrolyte battery, since the non-aqueous electrolyte contains the phosphate compound represented by the general formula (1) or the radical polymerization inhibitor, the non-aqueous electrolyte is made nonflammable and stored at a high temperature. The lower battery cycle characteristics are improved.

[0013]

Embodiments of the present invention will be described below.

FIG. 1 is a longitudinal sectional view showing one configuration example of the nonaqueous electrolyte battery of the present invention. The non-aqueous electrolyte battery 1 is formed by loading a wound body in which a film-shaped positive electrode 2 and a film-shaped negative electrode 3 are wound in close contact with a separator 4 inside a battery can 5. .

The positive electrode 2 is manufactured by applying a positive electrode mixture containing a positive electrode active material and a binder on a current collector and drying the mixture. A metal foil such as an aluminum foil is used for the current collector.

As the positive electrode active material, a metal oxide, a metal sulfide or a specific polymer can be used depending on the type of the intended battery.

For example, when constituting a lithium primary battery, TiS ₂ , MnO ₂ , graphite, F
eS ₂ or the like can be used. When a lithium secondary battery is configured, TiS ₂ ,
Metal sulfides or oxides such as MoS ₂ , NbSe ₂ , and V ₂ O ₅ can be used. Further, a lithium composite oxide mainly composed of LiM _x O ₂ (where M represents one or more transition metals and x varies depending on the charge / discharge state of the battery and is usually 0.05 or more and 1.10 or less). Things and the like can be used. As the transition metal M constituting the lithium composite oxide, Co, Ni, Mn, or the like is preferable. A specific example of such a lithium composite oxide is LiCo.
O ₂ , LiNiO ₂ , LiNi _y Co _1-y O ₂ (where 0 <
y <1. ), LiMn ₂ O _{4 and the} like. These lithium composite oxides can generate a high voltage and become positive electrode active materials excellent in energy density. The positive electrode 2 may use a plurality of these positive electrode active materials in combination.

As the binder of the above-mentioned positive electrode mixture, a known binder which is usually used for a positive electrode mixture of a battery can be used. Can be added.

The negative electrode 3 is manufactured by applying a negative electrode mixture containing a negative electrode active material and a binder on a current collector and drying the mixture. For the current collector, for example, a metal foil such as a copper foil is used.

In the case of forming a lithium primary battery or a lithium secondary battery, it is preferable to use lithium, a lithium alloy, or a material capable of doping or undoping lithium as a negative electrode material. As a material that can be doped and de-doped with lithium, for example, a carbon material such as a non-graphitizable carbon-based material and a graphite-based material can be used. Specifically, carbon materials such as pyrolytic carbons, cokes, graphites, glassy carbon fibers, fired organic polymer compounds, carbon fibers, and activated carbon can be used. Examples of the coke include pitch coke, needle coke, and petroleum coke. The fired organic polymer compound is obtained by firing a phenol resin, a furan resin or the like at an appropriate temperature and carbonizing the same.

In addition to the above-mentioned carbon materials, polymers that can be doped with and dedoped with lithium include polymers such as polyacetylene and polypyrrole and oxides such as SnO ₂ . Further, as the lithium alloy, a lithium-aluminum alloy or the like can be used.

As the binder for the above-mentioned negative electrode mixture, a known binder which is usually used for a negative electrode mixture of a lithium ion battery can be used, and a known additive for the above-mentioned negative electrode mixture can be used. Etc. can be added.

The non-aqueous electrolyte is prepared by dissolving an electrolyte in a non-aqueous solvent.

As the electrolyte, a known electrolyte usually used for a battery electrolyte can be used. Specifically, LiPF ₆ , LiBF ₄ , LiAsF ₆ , LiC
10 ₄ , LiCF ₃ SO ₃ , LiN (SO ₂ CF ₃ ) ₂ , Li
Lithium salts such as C (SO ₂ CF ₃ ) ₃ , LiAlCl ₄ , and LiSiF ₆ can be given. Among them, especially Li
PF ₆ and LiBF ₄ are desirable from the viewpoint of oxidation stability.

Such an electrolyte is contained in a non-aqueous solvent at a concentration of 0.1%.
Preferably, it is dissolved at a concentration of from mol / l to 3.0 mol / l. More preferably, 0.5 mol / l
２．０2.0 mol / l.

As the non-aqueous solvent, various non-aqueous solvents conventionally used for non-aqueous electrolytes can be used. For example, propylene carbonate, cyclic carbonates such as ethylene carbonate, chain carbonates such as diethyl carbonate and dimethyl carbonate, carboxylate esters such as methyl propionate and methyl butyrate, γ-butyl lactone, sulfolane, 2-methyltetrahydrofuran Ethers such as dimethoxyethane can be used. These non-aqueous solvents may be used alone or in combination of two or more. Among them, especially from the viewpoint of oxidation stability,
It is preferable to use a carbonate ester.

In the non-aqueous electrolyte battery 1 of the present invention,
The non-aqueous electrolyte contains a phosphate compound. By including a phosphate compound in the non-aqueous electrolyte,
In addition to making the non-aqueous solvent flame-retardant, the cycle characteristics of the non-aqueous electrolyte battery 1 can be improved.

As such a phosphate compound,
It is preferable to use the compound represented by the general formula (1) from the viewpoint of electrochemical stability.

[0029]

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Wherein R _{1 to} R ₄ are phenyl, benzyl, ortho, meta or para toluoyl or xylyl, and A is ortho, meta or para substituted phenyl or It is a substituted biphenyl group, an unsubstituted phenyl group, an unsubstituted biphenyl group, or bisphenol A.) As the phosphoric ester compound, an aromatic condensed phosphoric ester is preferable, and for example, R _{1 to} R ₄ are the same substituent. Examples include, but are not limited to, symmetric aromatic condensed phosphate esters, asymmetric aromatic condensed phosphate esters in which R _{1 to} R ₄ are different substituents, or halogen-substituted aromatic condensed phosphate esters. Not something. One of these phosphate ester compounds may be used alone, or a plurality of them may be used as a mixture.

The non-aqueous electrolyte preferably contains the phosphate compound represented by the general formula (1) at a ratio of 0.5% by weight to 20% by weight. If the amount of the phosphate ester compound is too small, the effect of increasing the flame retardancy of the non-aqueous electrolyte and the effect of suppressing the coating on the electrode surface and improving the cycle characteristics are not sufficient. On the other hand, if the amount of the phosphate ester compound is too large, the viscosity of the non-aqueous electrolyte increases and the electrical conductivity decreases. Therefore, by setting the content of the phosphate compound to 0.5% by weight to 20% by weight, the flame retardancy of the non-aqueous electrolyte is increased without lowering the conductivity of the non-aqueous electrolyte, and the cycle is further improved. Characteristics can be improved.

In the non-aqueous electrolyte battery 1, the non-aqueous electrolyte may contain a radical polymerization inhibitor. By including a radical polymerization inhibitor in the non-aqueous electrolyte,
A stable film can be formed on the electrode surface, and film growth can be suppressed. By suppressing the growth of the film on the electrode surface, it is possible to suppress deterioration of the cycle characteristics particularly under high-temperature storage and obtain good cycle characteristics.

As such a radical polymerization inhibitor,
It is preferable to use a phenothiazine compound represented by the general formula (2).

[0034]

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(Wherein R ₅ , R ₆ and R ₇ are a hydrogen atom, a substituted or unsubstituted linear or branched alkyl group, a cyclic saturated alkyl group substituted or unsubstituted with an element other than a hydrogen atom, Or X is absent or an oxygen atom of 1 to 2 integers.) Specific examples of such a phenothiazine compound include R
_{5 to} R ₇ are hydrogen atoms, phenothiazine, R ₅ is a methyl group, R ₆ and R ₇ are hydrogen atoms, 10-methylphenothiazine, R ₅ and R ₆ are hydrogen atoms, R ₇ is trifluoromethyl 2-trifluoromethylphenothiazine and the like.

Since the non-aqueous electrolyte battery 1 according to the present embodiment as described above contains a phosphate compound in the non-aqueous electrolyte, the flame retardancy of the non-aqueous electrolyte is increased and the cycle time is improved. The characteristics are improved and the reliability is excellent.
Further, since the non-aqueous electrolyte battery 1 contains a radical polymerization inhibitor in the non-aqueous electrolyte, the film growth on the electrode surface is suppressed, and the battery has good cycle characteristics.

And such a non-aqueous electrolyte battery 1 is
It is manufactured as follows.

The positive electrode 2 is uniformly coated with a positive electrode mixture containing a positive electrode active material and a binder on a metal foil such as an aluminum foil, which serves as a positive electrode current collector, and dried to form a positive electrode active material layer. It is produced by forming. Known binders can be used as the binder of the positive electrode mixture, and known additives and the like can be added to the positive electrode mixture.

The negative electrode 3 is uniformly coated with a negative electrode mixture containing a negative electrode active material and a binder on a metal foil such as a copper foil, which serves as a negative electrode current collector, and dried to form a negative electrode active material layer. It is produced by forming. As the binder of the negative electrode mixture, a known binder can be used, and a known additive or the like can be added to the negative electrode mixture.

The positive electrode 2 and the negative electrode 3 obtained as described above are brought into close contact with each other via a separator 4 made of, for example, a microporous polypropylene film, and wound in a spiral form many times to form a wound layer body. Is done.

Next, the insulating plate 6 is inserted into the bottom of the battery can 5 made of nickel, the inside of which is plated with nickel, and the wound body is further housed. Then, in order to collect the current of the negative electrode, one end of a negative electrode lead 7 made of, for example, nickel is pressed against the negative electrode 3 and the other end is welded to the battery can 5. Thereby, the battery can 5
Has conductivity with the negative electrode 3 and becomes an external negative electrode of the nonaqueous electrolyte battery 1. In order to collect the current of the positive electrode 2, one end of a positive electrode lead 8 made of, for example, aluminum is connected to the positive electrode 2.
To the battery cover 1 at the other end via a current interrupting thin plate 9.
0 is electrically connected. The current interrupting thin plate 9 interrupts the current in accordance with the internal pressure of the battery. This allows
The battery lid 10 has conductivity with the positive electrode 2, and serves as an external positive electrode of the nonaqueous electrolyte battery 1.

Next, a non-aqueous electrolyte is injected into the battery can 5. This non-aqueous electrolyte is prepared by dissolving an electrolyte in a non-aqueous solvent. Here, the non-aqueous electrolyte contains a phosphate compound or a radical polymerization inhibitor.

Next, the battery cover 5 is fixed by caulking the battery can 5 through the insulating sealing gasket 11 coated with asphalt, and the cylindrical nonaqueous electrolyte battery 1 is manufactured.

In this non-aqueous electrolyte battery 1,
As shown in FIG. 1, a center pin 12 connected to the negative electrode lead 7 and the positive electrode lead 8 is provided, and a safety valve device for bleeding gas when the pressure inside the battery becomes higher than a predetermined value. 13 and a PTC element 14 for preventing a rise in temperature inside the battery.

In the above embodiment, the non-aqueous electrolyte battery 1 using the non-aqueous electrolyte has been described as an example.
The present invention is not limited to this, but is also applicable to a gel electrolyte battery using a gel electrolyte containing a matrix polymer composed of a single or a mixture of conductive polymer compounds and a swelling solvent.

Examples of the matrix polymer include ether polymers such as polyethylene oxide and crosslinked products thereof, polymethacrylate esters, acrylates, polyvinylidene fluoride, and copolymers of vinylidene fluoride and hexafluoropropylene. Fluorinated polymers and the like are listed. One of these polymers may be used alone, or a plurality of them may be used as a mixture.
Among them, from the viewpoint of oxidation-reduction stability, it is preferable to use a fluorine-based polymer such as polyvinylidene fluoride or a copolymer of vinylidene fluoride and hexafluoropropylene.

Further, in the above-described embodiment, a description has been given by taking a secondary battery as an example. However, the present invention is not limited to this, and can be applied to a primary battery. In addition, the battery of the present invention has a cylindrical shape, a square shape, a coin shape, a button shape, and the like, and its shape is not particularly limited,
In addition, various sizes such as a thin type and a large size can be used.

[0048]

EXAMPLE A non-aqueous electrolyte battery as described above was manufactured.

Example 1 First, a negative electrode was manufactured as follows.

First, petroleum pitch was used as a starting material and calcined at 1000 ° C. in an inert gas stream to obtain a non-graphitizable carbon material having properties similar to glassy carbon. When an X-ray diffraction measurement was performed on the non-graphitizable carbon material, the (002) plane spacing was 3.76 Å, and the true specific gravity was 1.58 g / cm ³ .

Next, the obtained non-graphitizable carbon material was pulverized to obtain a carbon material powder having an average particle diameter of 10 μm. 90 parts by weight of the carbon material powder and 10 parts by weight of the binder were mixed to prepare a negative electrode mixture. Here, polyvinylidene fluoride was used as the binder.

Finally, the negative electrode mixture was dispersed in N-methyl-2-pyrrolidone to form a slurry. Then, this slurry was uniformly applied to both surfaces of a 10 μm-thick strip-shaped copper foil as a negative electrode current collector, dried to form a negative electrode active material layer, and then compression-molded with a roll press to prepare a negative electrode. .

Next, a positive electrode was prepared as follows.

First, lithium carbonate and cobalt carbonate were mixed at a ratio of 0.5 mol to 1 mol, and 900
Calcination was performed at 5 ° C. for 5 hours to obtain LiCoO _{2 serving} as a positive electrode active material.

Next, 91 parts by weight of the obtained LiCoO ₂ , 6 parts by weight of a conductive agent, and 10 parts by weight of a binder were mixed to prepare a positive electrode mixture. Here, graphite was used as the conductive agent, and a copolymer of vinylidene fluoride and hexafluoropropylene was used as the binder.

Finally, the positive electrode mixture was dispersed in N-methyl-2-pyrrolidone to form a slurry. Then, this slurry was uniformly applied on one surface of a 20-μm-thick aluminum foil serving as a positive electrode current collector, dried to form a positive electrode active material layer, and then compression-molded with a roll press to produce a positive electrode.

The positive electrode and the negative electrode obtained as described above are brought into close contact with each other via a separator made of a microporous polypropylene film having a thickness of 25 μm, and are wound in a spiral form many times to form a wound layer body. did.

Next, an insulating plate was inserted into the bottom of a nickel-plated iron battery can, and the wound body was further housed. Then, in order to collect the current of the negative electrode, one end of a nickel negative electrode lead was pressed against the negative electrode, and the other end was welded to the battery can. Further, in order to collect the current of the positive electrode, one end of an aluminum positive electrode lead was attached to the positive electrode, and the other end was electrically connected to the battery lid via a current interrupting thin plate. The current interrupting thin plate interrupts the current according to the internal pressure of the battery.

Then, a non-aqueous electrolyte was injected into the battery can. This non-aqueous electrolyte contains 40% by weight of propylene carbonate, 40% by weight of dimethyl carbonate, 2% by weight of a phosphate compound, and 0.5% by weight of a radical polymerization inhibitor.
Was prepared by mixing

Here, the phosphoric acid ester compound includes:
Compound 1 in which R _{1 to} R ₄ and A in the general formula (1) are substituents as shown in Table 1 was used.

[0061]

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The radical polymerization inhibitor includes, as a phenothiazine compound which is a heterocyclic compound containing nitrogen and sulfur, R _{5 to} R ₇ and X as shown in the general formula (2) in Table 4. Compound 15, which is a substituent as shown, was used.

[0063]

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Finally, the battery lid is fixed by caulking the battery can via an insulating sealing gasket coated with asphalt to produce a cylindrical non-aqueous electrolyte battery having a diameter of about 18 mm and a height of about 65 mm. did.

Example 2 The procedure of Example 2 was repeated except that 2% by weight of a compound 2 as a phosphate compound and 0.5% by weight of a compound 15 as a radical polymerization inhibitor were added to a non-aqueous electrolyte. A non-aqueous electrolyte battery was produced in the same manner as in Example 1.

Example 3 The procedure of Example 3 was repeated except that 2% by weight of compound 3 was added as a phosphate compound and 0.5% by weight of compound 16 was used as a radical polymerization inhibitor. A non-aqueous electrolyte battery was produced in the same manner as in Example 1.

Example 4 The procedure of Example 4 was repeated except that 2% by weight of a compound 4 was added as a phosphate compound and 0.5% by weight of a compound 16 was used as a radical polymerization inhibitor. A non-aqueous electrolyte battery was produced in the same manner as in Example 1.

Example 5 The procedure of Example 5 was repeated except that 2% by weight of the compound 5 was added as a phosphate compound and 0.5% by weight of the compound 17 was used as a radical polymerization inhibitor. A non-aqueous electrolyte battery was produced in the same manner as in Example 1.

Example 6 The procedure of Example 6 was repeated except that 2% by weight of the compound 6 was added as a phosphate compound and 0.5% by weight of the compound 17 was used as a radical polymerization inhibitor. A non-aqueous electrolyte battery was produced in the same manner as in Example 1.

Example 7 The procedure of Example 7 was repeated except that 2% by weight of a compound 7 was added as a phosphate compound and 0.5% by weight of a compound 18 was used as a radical polymerization inhibitor. A non-aqueous electrolyte battery was produced in the same manner as in Example 1.

Example 8 The procedure of Example 8 was repeated except that 2% by weight of a compound 8 was added as a phosphate compound and 0.5% by weight of a compound 18 was used as a radical polymerization inhibitor. A non-aqueous electrolyte battery was produced in the same manner as in Example 1.

Example 9 The procedure of Example 9 was repeated except that 2% by weight of a compound 9 was added as a phosphate compound and 0.5% by weight of a compound 19 was used as a radical polymerization inhibitor. A non-aqueous electrolyte battery was produced in the same manner as in Example 1.

Example 10 The procedure of Example 10 was repeated except that 2% by weight of a compound 10 was added as a phosphate compound and 0.5% by weight of a compound 19 was used as a radical polymerization inhibitor. A non-aqueous electrolyte battery was produced in the same manner as in Example 1.

Example 11 The procedure of Example 11 was repeated except that 2% by weight of the compound 11 was added as a phosphate compound and 0.5% by weight of the compound 15 was used as a radical polymerization inhibitor. A non-aqueous electrolyte battery was produced in the same manner as in Example 1.

Example 12 The procedure of Example 12 was repeated except that 2% by weight of the compound 12 was added as a phosphate compound and 0.5% by weight of the compound 16 was used as a radical polymerization inhibitor. A non-aqueous electrolyte battery was produced in the same manner as in Example 1.

Example 13 The procedure of Example 13 was repeated except that 2% by weight of the compound 13 was added as a phosphate compound and 0.5% by weight of the compound 15 was used as a radical polymerization inhibitor. A non-aqueous electrolyte battery was produced in the same manner as in Example 1.

Example 14 The procedure of Example 14 was repeated except that 2% by weight of the compound 14 was added as a phosphate compound and 0.5% by weight of the compound 15 was used as a radical polymerization inhibitor. A non-aqueous electrolyte battery was produced in the same manner as in Example 1.

Example 15 In a non-aqueous electrolyte, 1.5% by weight of compound 1 as a phosphate compound, 0.5% by weight of compound 7 and 1% by weight of compound 15 as a radical polymerization inhibitor. %, And a non-aqueous electrolyte battery was prepared in the same manner as in Example 1.

Example 16 In a non-aqueous electrolyte, 0.5% by weight of Compound 1 as a phosphate compound, 0.5% by weight of Compound 9 and 0.1% of Compound 16 as a radical polymerization inhibitor were added. Example 1 except that 5% by weight was added.
A non-aqueous electrolyte battery was produced in the same manner as in the above.

Example 17 In a non-aqueous electrolyte, 0.5% by weight of Compound 2 and 0.5% by weight of Compound 10 as phosphoric ester compounds and 0.1% of Compound 17 as a radical polymerization inhibitor were added. A non-aqueous electrolyte battery was produced in the same manner as in Example 1, except that 5% by weight was added.

Example 18 In a non-aqueous electrolytic solution, 1% by weight of compound 4 as a phosphoric acid ester compound, 0.5% by weight of compound 8 and compound 18 as a radical polymerization inhibitor
Was added in the same manner as in Example 1 except that 0.5% by weight was added.

Example 19 A non-aqueous electrolyte battery was manufactured in the same manner as in Example 1, except that 1% by weight of Compound 16 was added as a radical polymerization inhibitor to the non-aqueous electrolyte.

Example 20 In a non-aqueous electrolyte, 1% by weight of a compound 15 as a radical polymerization inhibitor and a compound 17 were added.
Was added in the same manner as in Example 1 except that 1% by weight was added to prepare a nonaqueous electrolyte battery.

Example 21 A non-aqueous electrolyte battery was manufactured in the same manner as in Example 1, except that 1.5% by weight of Compound 15 was added as a radical polymerization inhibitor to the non-aqueous electrolyte.

Example 22 In a non-aqueous electrolyte, 1% by weight of Compound 3 as a phosphate compound was added to Compound 14
And a non-aqueous electrolyte battery was prepared in the same manner as in Example 1, except that 1% by weight of Compound No. 1 and 0.5% by weight of Compound 15 as a radical polymerization inhibitor were added.

Example 23 1% by weight of a compound 7 as a phosphate compound in a non-aqueous electrolyte solution was added to a compound 13
And a non-aqueous electrolyte battery was prepared in the same manner as in Example 1, except that 1% by weight of Compound No. 1 and 0.5% by weight of Compound 16 as a radical polymerization inhibitor were added.

Example 24 1% by weight of a compound 7 as a phosphate compound in a non-aqueous electrolyte solution was added to a compound 14
And a non-aqueous electrolyte battery was prepared in the same manner as in Example 1 except that 1% by weight of the compound was added and 0.5% by weight of the compound 17 as a radical polymerization inhibitor.

Example 25 In a non-aqueous electrolyte, 1% by weight of a compound 8 as a phosphate compound was added to a compound 14
And a non-aqueous electrolyte battery were prepared in the same manner as in Example 1, except that 1% by weight of Compound No. 1 and 0.5% by weight of Compound 18 as a radical polymerization inhibitor were added.

Comparative Example 1 The procedure of Example 1 was repeated except that the amount of propylene carbonate was 50% by weight, the amount of dimethyl carbonate was 50% by weight, and no phosphate compound or radical polymerization inhibitor was added. Similarly, a non-aqueous electrolyte battery was manufactured.

Comparative Example 2 A non-aqueous electrolyte battery was prepared in the same manner as in Example 1 except that 5% by weight of a hydroquinone compound was added as an antioxidant without using a phosphate compound and a radical polymerization inhibitor. Was prepared.

Here, each of the above-described embodiments used:
Tables 1 to 3 show specific examples of the substituents R _{1 to} R ₄ and A of the phosphate compound (compound 1 to compound 14) represented by the general formula (1).

[0092]

[Table 1]

[0093]

[Table 2]

[0094]

[Table 3]

Further, the radical polymerization inhibitor represented by the general formula (2) (compound 15) used in each of the above Examples was used.
Table 4 shows specific examples of the substituents R _{5 to} R ₇ and X of the compound 19).

[0096]

[Table 4]

Table 5 summarizes the types and amounts of the compounds added to the nonaqueous electrolytes of the batteries prepared in Examples 1 to 25.

[0098]

[Table 5]

For each of the non-aqueous electrolyte batteries produced as described above, the initial discharge capacity, the discharge capacity retention after 100 cycles, the load characteristics, and the self-discharge characteristics were evaluated.

In order to check the initial discharge capacity, a constant current and constant voltage charge of 1 A was performed on each nonaqueous electrolyte battery to an upper limit of 4.2 V for 3 hours at 23 ° C., and then a constant current of 1000 mA was applied. The initial discharge capacity was determined by performing the discharge up to a final voltage of 2.5V.

In order to observe the discharge capacity retention ratio, charge / discharge was performed 100 cycles under the same charge / discharge conditions as described above, and the ratio of the discharge capacity at the 100th cycle to the initial discharge capacity was determined.

In order to check the load characteristics, one cycle of charge / discharge was performed under the same conditions as the above-mentioned charge / discharge conditions, and the same charge was performed.
V, and the discharge capacity retention rate of 2000 mA was determined when the discharge capacity of 700 mA was 100.

In order to check the self-discharge characteristics, the battery was charged under the same charging conditions as described above, left in an atmosphere at 60 ° C., and taken out after 10 days. Five hours after the battery was removed, the battery was discharged at 23 ° C. at 700 mA. Then, the discharge capacity retention ratio after storage with respect to the discharge capacity before being left in an atmosphere at 60 ° C. was determined, and the difference was determined as the self-discharge rate.

Table 6 shows the results of evaluation of the initial capacity, discharge capacity retention, load characteristics and self-discharge characteristics of each nonaqueous electrolyte battery.

[0105]

[Table 6]

As is clear from Table 6, the non-aqueous electrolyte batteries of Examples 1 to 25 in which the electrolyte solution contains a phosphate compound and a radical polymerization inhibitor were the same as those of Comparative Examples 1 and 2. The initial discharge capacity is larger than that of the water electrolyte battery, and 2000 m for a discharge capacity of 700 mA.
The discharge capacity retention ratio of A was also high, and very excellent results were obtained. Also, the cycle characteristics and the self-discharge characteristics were at a level without any problem.

Further, the following Embodiments 26 and 27 will be described.
In Comparative Example 3, a nonaqueous electrolyte battery was prepared using a mixed solvent of ethylene carbonate and diethyl carbonate as a solvent for the nonaqueous electrolyte.

Example 26 As a solvent for a non-aqueous electrolyte,
A mixed solvent obtained by adding 2% by weight of Compound 4 as a phosphate compound and 0.5% by weight of Compound 15 as a radical polymerization inhibitor to a mixed solution of equal volumes of ethylene carbonate and diethyl carbonate was used. Further, graphite (Lonza Co., Ltd.) is used instead of the non-graphitizable material as a constituent material of the negative electrode.
S-75: A nonaqueous electrolyte battery was produced in the same manner as in Example 1, except that the (plane spacing of the (002) plane = 3.358) was used.

Example 27 As a solvent for a non-aqueous electrolyte,
Compound 5 as a phosphate compound was added in an equal volume mixed solution of ethylene carbonate and diethyl carbonate at 0.5% by weight,
As a radical polymerization inhibitor, a mixed solvent to which Compound 16 and 0.5% by weight were added was used. Further, instead of the non-graphitizable material, graphite (KS-75 manufactured by Lonza Co., Ltd .: spacing between (002) planes = 3.358) as a constituent material of the negative electrode.
A non-aqueous electrolyte battery was produced in the same manner as in Example 1 except that was used.

Comparative Example 3 50% by volume of ethylene carbonate and 50% by volume of diethyl carbonate were used as the solvent of the non-aqueous electrolyte without using the phosphate compound and the radical polymerization inhibitor.
% (Volume%), and graphite (KS-75 manufactured by Lonza Co., Ltd .: plane spacing of (002) plane = 3.358) instead of the non-graphitizable material as a constituent material of the negative electrode
A non-aqueous electrolyte battery was produced in the same manner as in Example 1 except that the above-mentioned method was used.

The non-aqueous electrolyte batteries produced as described above were similarly evaluated for the initial discharge capacity, the discharge capacity retention rate after 100 cycles, the load characteristics, and the self-discharge characteristics. Table 7 shows the evaluation results.

[0112]

[Table 7]

As is clear from Table 7, even when graphite was used as the negative electrode material, the nonaqueous electrolyte batteries of Examples 26 and 27 in which the electrolyte contained a phosphate ester compound and a radical polymerization inhibitor were used. Has a larger initial discharge capacity than the non-aqueous electrolyte battery of Comparative Example 3, and
The discharge capacity maintenance ratio of 2000 mA with respect to the discharge capacity of mA was also high, and very excellent results were obtained. Also, the cycle characteristics and the self-discharge characteristics were at a satisfactory level.

The following Example 28 and Comparative Example 4
Then, a battery was configured using a gel electrolyte instead of the non-aqueous electrolyte.

Example 28 First, a negative electrode and a positive electrode were manufactured in the same manner as in Example 1.

Next, a gel electrolyte was formed. To form a gel electrolyte, first, 0.5% by weight of compound 4 as a phosphate compound and 0.5% of compound 15 as a radical polymerization inhibitor were added to an equal volume mixed solution of ethylene carbonate and propylene carbonate. The mixture was added at a ratio of% by weight to obtain a mixed solvent. Then, 1 mol / mol of LiPF ₆ was added to this mixed solvent.
1 was dissolved to obtain a plasticizer.

Next, 30 parts by weight of this plasticizer, 10 parts by weight of polyvinylidene fluoride, and 6 parts of dimethyl carbonate were added.
A solution prepared by mixing and dissolving 0 parts by weight was uniformly applied on the negative electrode and the positive electrode, impregnated, and allowed to stand at room temperature for 8 hours to vaporize and remove dimethyl carbonate to obtain a gel electrolyte electrode.

The negative electrode and the positive electrode coated with the gel electrolyte are brought into contact with each other by pressing the gel electrolyte side, and are pressed to have an area of 2.
A flat gel electrolyte battery having a size of 5 cm × 4.0 cm and a thickness of 0.3 mm was produced. In the flat gel electrolyte battery, the negative electrode and the positive electrode were housed in an outer package made of a laminate film, and leads were drawn out of each electrode.

Comparative Example 4 A gel electrolyte battery was produced in the same manner as in Example 28 except that the phosphate ester compound and the radical polymerization inhibitor were not mixed with the plasticizer.

The gel electrolyte battery manufactured as described above was evaluated for initial discharge capacity, discharge capacity retention, load characteristics, and self-discharge characteristics.

In order to check the initial discharge capacity, the gel electrolyte battery was charged at a constant current and a constant voltage of 15 mA to an upper limit of 4.2 V for 3 hours at 23 ° C., and then a constant current discharge of 15 mA was performed. The initial discharge capacity was determined by performing the operation up to a final voltage of 2.5 V.

In order to observe the discharge capacity retention ratio, charge / discharge was performed 100 cycles under the same charge / discharge conditions as described above, and the ratio of the discharge capacity at the 100th cycle to the initial discharge capacity was determined.

In order to examine the load characteristics, one cycle of charge / discharge was performed under the same conditions as the charge / discharge conditions described above, and the same charge was performed. Then, a constant current discharge of 60 mA was performed to a final voltage of 2.5 V, and a discharge of 15 mA was performed. 60 when the discharge capacity is 100
The discharge capacity retention rate of mA was determined.

Further, in order to check the self-discharge characteristics, the battery was charged under the same charging conditions as described above, left in an atmosphere at 60 ° C., and taken out after 10 days. Five hours after the battery was taken out, the battery was discharged at 23 mA at 15 mA. Then, the discharge capacity retention ratio after storage with respect to the discharge capacity before being left in an atmosphere at 60 ° C. was determined, and the difference was determined as the self-discharge rate.

Table 8 shows the results of evaluation of the initial capacity, discharge capacity retention, load characteristics, and self-discharge characteristics of each gel electrolyte battery.

[0126]

[Table 8]

As can be seen by comparing Example 28 with Comparative Example 4, the electrolyte is not limited, and the effect of the present invention can be obtained even when a gel electrolyte is used.

[0128]

The non-aqueous electrolyte battery of the present invention has excellent cycle characteristics because the non-aqueous electrolyte contains a phosphate compound or a radical polymerization inhibitor.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing one configuration example of a nonaqueous electrolyte battery of the present invention.

[Explanation of symbols]

1 Non-aqueous electrolyte battery, 2 Positive electrode, 3 Negative electrode, 4
Separator, 5 Battery can, 10 Battery lid

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Ken Segawa 6-35 Kita Shinagawa, Shinagawa-ku, Tokyo Sony Corporation F-term (reference) 5H029 AJ04 AJ05 AJ07 AJ12 AJ15 AK02 AK03 AK05 AL02 AL06 AL07 AL08 AL12 AL16 AM00 AM03 AM04 AM05 AM07 BJ02 BJ14 DJ09 EJ11 HJ02

Claims (10)

[Claims] A positive electrode having a positive electrode active material, a negative electrode having a negative electrode active material disposed opposite to the positive electrode, and a non-aqueous electrolyte interposed between the positive electrode and the negative electrode; The non-aqueous electrolyte contains a phosphate compound represented by the general formula (1) or a radical polymerization inhibitor. (Wherein, R _{1 to} R ₄ represent a substituted or unsubstituted cyclic aromatic group, and A represents a substituted or unsubstituted cyclic aromatic group or a heterocyclic ring). 2. The phosphoric ester compound has a substituent R
_{1 to} R ₄ are a phenyl group, a benzyl group, an ortho, meta or para-position toluoyl group or a xylyl group, and the substituent A is an ortho, meta or para-position substituted phenyl group or a substituted biphenyl group, an unsubstituted phenyl group; The non-aqueous electrolyte battery according to claim 1, wherein the non-aqueous electrolyte battery is a group, an unsubstituted biphenyl group, or bisphenol A. 3. The non-aqueous electrolyte battery according to claim 1, wherein the radical polymerization inhibitor is a heterocyclic compound containing nitrogen and sulfur. 4. The heterocyclic compound containing nitrogen and sulfur is a phenothiazine compound represented by the general formula (2). (Wherein, R ₅ , R ₆ and R ₇ are a hydrogen atom, a substituted or unsubstituted linear or branched alkyl group, a cyclic saturated alkyl group substituted or unsubstituted with an element other than a hydrogen atom, X is absent or 1-2
Is an integer number of oxygen atoms. The non-aqueous electrolyte battery according to claim 3, wherein 5. The phenothiazine compound represented by the general formula (2), wherein R _{5 to} R ₇ are hydrogen atoms, R ₅ is a methyl group, and R ₆ and R ₇ are hydrogen atoms. - methyl phenothiazine, by R ₅ and R ₆ is a hydrogen atom, a non-aqueous electrolyte battery according to claim 4, wherein the R ₇ is any of 2-trifluoromethyl-phenothiazine is trifluoromethyl. 6. The non-aqueous electrolyte battery according to claim 1, wherein the positive electrode contains a composite oxide of lithium and a transition metal. 7. The non-aqueous electrolyte battery according to claim 1, wherein the negative electrode contains a material capable of doping and / or undoping lithium. 8. The non-aqueous electrolyte battery according to claim 7, wherein the material capable of doping and / or undoping lithium is a carbon material. 9. The non-aqueous electrolyte battery according to claim 1, wherein the non-aqueous electrolyte is a non-aqueous electrolyte obtained by dissolving an electrolyte in a non-aqueous solvent. 10. The non-aqueous electrolyte battery according to claim 1, wherein the non-aqueous electrolyte is a gel electrolyte containing a conductive polymer compound and a swelling solvent.