JP2002042815A - Non-aqueous secondary battery - Google Patents

Abstract

(57) [Summary] (Modifications) [PROBLEMS] To provide a novel electrode which can solve the drawbacks of lithium-containing manganese spinel, which is a positive electrode active material, and can improve battery capacity. A general formula _Li a _Co b _Al c Mn
_(2-b-c) general formula _{O 4} in which manganese spinel compound (A) and the modified lithium cobaltate _Li a Mn _b
Fe _c Al _d Co is _(1-b-c-d ) O 2 (B)
(A) is mixed at 10 to 80% by weight, (B) is mixed at 90 to 20% by weight, and spherical or fibrous artificial graphite or aromatic hydrocarbon as a carbonaceous material is coated by CVD. , A multi-layer carbonaceous material consisting of granular, polygonal natural graphite, spherical, granular, polygonal artificial graphite obtained by coating and carbonizing the surface with pitch phenolic resin Next battery.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001] The present invention relates to a non-aqueous secondary battery.

[0002] In recent years, lithium ion secondary batteries using lithium cobalt oxide as the active material for the positive electrode have been used as power sources for various electronic devices. In order to reduce the size and weight of electronic devices, they are extremely useful as power supplies for these electronic devices. There is a demand for a battery capable of responding to a sudden increase in demand by utilizing a richer transition metal as a resource to reduce the cobalt ratio while maintaining a high capacity as a battery. The present invention
The present invention relates to a novel non-aqueous secondary battery that can satisfy the demand.

[PRIOR ART] Lithium cobaltate (Li)
CoO ₂ ) is widely used as a positive electrode active material of a lithium ion secondary battery, but at a charge voltage of 4.2 V or more as a lithium ion secondary battery in combination with a negative electrode using a carbonaceous material as an active material, Repeated charging / discharging causes the capacity to drop significantly, the gas pressure in the battery to rise with the decomposition of the electrolyte, causing liquid leakage or opening the safety valve. A strict voltage control electronic circuit is required, and it has been difficult for the battery of the power supply of the electronic device to be expensive. In addition, it has been proposed to replace the positive electrode with lithium nickel oxide because it has more abundant resources as a metal, is less expensive than cobalt, and can achieve a higher capacity. It is insufficient, and it has been found that when the charge voltage is increased to 4.20 V, which is equivalent to that of lithium cobalt oxide, the cycle life is remarkably reduced when charge and discharge are repeated, so that it cannot be put to practical use. In addition, LiNi _0.7 Co _0.2 Mn _0.1
N ₂ such as O ₂ and LiNi _0.6 Co _0.3 Mn _0.1 O ₂
Although i-Co-Mn has been proposed, the ratio of cobalt is high, which is insufficient from the viewpoint of economy, and it has not reached the level of lithium cobalt oxide even with overcharge resistance. LiNi
_0.8 Co _0.15 Al _0.05 O ₂ , LiNi _0.8
In Co _0.10 Al _0.10 O _{2 and the} like, although the ratio of cobalt is slightly reduced and a high discharge capacity can be obtained,
Its overcharge resistance is inferior to lithium cobalt oxide. In addition, repeated charging and discharging up to 4.3 V shortens the cycle life, which is not practical. Lithium-containing manganese spinel compounds have attracted attention for a long time because of their abundant manganese resources and economical economy. As a proposal for improving the discharge capacity decrease due to elution, the lithium / manganese ratio is reduced from 1/2 to 1.06 to 1.08 / 2.
And replacing some of the manganese element with chromium, aluminum, nickel, cobalt, and iron to further increase the lithium richness. However,
While the reduction in discharge capacity at high temperatures is remarkably improved, 4.3.
Even when charged up to V, the initial discharge capacity is 8-20%
At the expense of reduced sacrifice (down from 125 mAh / g to 100-115 mAh / g). The lithium-containing manganese spinel compound alone is practically difficult for small and lightweight electronic devices that require a high-capacity battery as a power source. Manganese-rich spinel (eg, Li
_1.06 Mn ₂ O ₄ ) or any one of the above lithium nickelates, and adding lithium nickelate having a relatively high discharge capacity due to the low discharge capacity of manganese spinel. Attempts have been made to develop a discharge capacity close to or comparable to lithium cobalt oxide, but since it is based on the above-mentioned lithium nickel oxide, whose thermal stability has not been improved, a voltage of 4.3 V
The cycle life was not improved by repeating charge and discharge up to. In terms of occupational health, such powdered nickel compounds require strict control as carcinogenic substances.

[0004] The present invention has solved the disadvantage of the conventional lithium-containing manganese spinel, which is a positive electrode active material, and has developed a 4.2 V lithium-ion secondary battery as a non-aqueous secondary battery. By improving the overcharge resistance and improving the battery capacity,
An object of the present invention is to provide a new positive electrode that can achieve high capacity and long life.

[Means for Solving the Problems] As a result of various studies on the above problems, the present inventors have prepared a specific modified lithium cobalt oxide independently and mixed it with a specific lithium-containing manganese spinel. Thus, in a specific compounding ratio range, a new economical Li-Mn-Co-based positive electrode with a reduced cobalt ratio was found, and by combining with a specific negative electrode active material, the conventional disadvantages of lithium ion The present invention has found a non-aqueous secondary battery capable of achieving higher capacity and longer life by improving the overcharge resistance at 4.2 V or higher as a secondary battery and enabling the battery capacity to be improved. Was completed.

[Embodiment of the Invention] The present invention will be specifically described below. That is, the present invention provides: (1) a non-aqueous secondary battery including a positive electrode using a lithium composite metal oxide as an active material and a negative electrode using a carbonaceous material as an active material, wherein the positive electrode has a general formula of Li _a Co _b Al _c Mn _(2-bc) O ₄ (where a, b, and c are each 1.03 ≦ a ≦ 1.06,
0.015 ≦ b ≦ 0.05 and 0 ≦ c ≦ 0.05. ) Manganese spinel compound is (A) and the general formula _{Li a Mn b Fe c Al d} Co (1-b-c-d) O 2
(However, a, b, c, and d are each 1.00 ≦ a ≦
1.03, 0.00005 ≦ b ≦ 0.009, 0.00
005 ≦ c ≦ 0.005 and 0 ≦ d ≦ 0.01. ) Is mixed with the modified lithium cobaltate (B),
(A) not less than 10% by weight and not more than 80% by weight, and (B) not more than 90% by weight and not less than 20% by weight, and (2) a lithium composite metal oxide as an active material. In a non-aqueous secondary battery including a positive electrode and a negative electrode using a carbonaceous material as an active material, the negative electrode is spherical, artificial fibrous graphite, granular, polygonal natural graphite,
Multi-layer carbonaceous material obtained by coating artificial graphite with aromatic hydrocarbon by CVD method, or coating and carbonizing pitch etc. on the surface and coating coke etc., alone or a mixture thereof selected from coke It is a non-aqueous secondary battery characterized by the following. The present invention is characterized in that a manganese spinel-based compound (A) and a modified lithium cobaltate (B) are independently prepared and a specific blending ratio is obtained, and a manganese spinel-based compound obtained with the same composition after blending (C) or modified lithium cobaltate (D)
Then, high capacity which is one of the effects of the present invention cannot be exhibited.

In the present invention, a specific modified lithium cobaltate compound which withstands a charge of 4.3 V and has a discharge capacity much higher than that of these lithium-containing manganese spinel compounds is prepared independently, and these are mixed and easily prepared. Thus, a positive electrode having a novel composition can be provided. Even if charging is repeated at a voltage of 4.20 V or more in a lithium ion secondary battery in which a positive electrode is combined with a carbonaceous material as a negative electrode, the discharge capacity is not significantly reduced, the cycle life is not shortened, and overcharging occurs. As a result, it is possible to suppress an increase in pressure inside the battery can caused by gas generation due to decomposition of the electrolytic solution, and to avoid an expensive electronic circuit incorporating a strict charge voltage monitoring and control mechanism. The present invention is expected to be a positive electrode active material capable of reducing the weight and size of a battery, while reducing the cost as a power source according to the present invention. The lithium-containing manganese spinel compound (A) used in the present invention has a general formula of Li _a Co _b Al _c Mn.
_(2- bc ₎ O ₄ (where a, b, and c are respectively 1.03 ≦ a ≦ 1.06, 0.015 ≦ b ≦ 0.05,
Represents the number 0 ≦ c ≦ 0.05. ), Electrolytic manganese dioxide, trimanganese tetroxide, manganese carbonate, manganese acetate, manganese citrate and at least one manganese compound and cobalt carbonate, cobalt acetate, cobalt oxalate,
Lithium hydroxide, lithium carbonate, acetic acid and at least one of cobalt compounds such as cobalt hydroxide, tricobalt tetroxide and cobalt monoxide and, if necessary, at least one aluminum compound such as aluminum hydroxide, aluminum acetate and aluminum nitrate 650 ° C. to 850 ° C., preferably 700 ° C. using at least one of lithium compounds such as lithium and lithium iodide so as to obtain the above composition.
It is obtained by firing at a temperature of ８００800 ° C. Except for the composition range of the manganese spinel compound (A), high temperature (50
-55 ° C.) and 4.3.
It is difficult to obtain an initial discharge capacity of 105 mAh / g or more in V charging. Preferably, the general formula Li _a Co _b Al
a, b, and c of _c Mn _(2- bc ₎ O ₄ are 1.04 ≦ a ≦ 1.06, 0.035 ≦ b ≦ 0.05, respectively.
It is in the range of 0 ≦ c ≦ 0.05. Modified lithium cobaltate (B) used in the present invention General formula Li _a Mn _b Fe
_{c Al d Co (1-b} -c-d) O 2 ( where, a, b,
c and d are 1.00 ≦ a ≦ 1.03 and 0.00, respectively.
005 ≦ b ≦ 0.009, 0.00005 ≦ c ≦ 0.0
05, 0 ≦ d ≦ 0.01. ), At least one of cobalt compounds such as tricobalt tetroxide, cobalt hydroxide, cobalt monoxide, cobalt carbonate, cobalt acetate, and cobalt oxalate, and manganese acetate, manganese citrate, manganese carbonate, electrolytic manganese dioxide, At least one manganese compound such as trimanganese oxide and at least one iron compound such as iron oxalate, iron acetate, iron formate and iron nitrate and, if necessary, at least an aluminum compound such as aluminum hydroxide, aluminum acetate and aluminum nitrate. 1
A temperature of 750 ° C. to 1050 ° C., preferably 850 ° C. to 950 ° C., using the seed and at least one kind of lithium compound such as lithium hydroxide, lithium carbonate, lithium acetate, lithium iodide, etc. And calcined. Outside the composition range of the modified lithium cobaltate (B), the overcharge resistance at 4.2 V or more is improved, and
It is difficult to obtain an initial discharge capacity of 148 mAh / g or more in 3V charging. Preferably, the general formula Li _a Mn _b F
_{e c Al d Co (1-} b-c-d) of the _{O 2} a, b, c,
d is 1.00 ≦ a ≦ 1.01, 0.001 ≦
b ≦ 0.005, 0.0003 ≦ c ≦ 0.001, 0 ≦
d ≦ 0.005. When (A) is less than 10% by weight ((B) exceeds 90% by weight), the improvement in economic efficiency due to the reduction of the cobalt ratio is small, and the mixed synergistic effect is hardly observed. When (B) is less than 20% by weight, ((A)
% By weight), the battery capacity is as low as that of the lithium-containing manganese spinel compound before the improvement of high-temperature thermal stability, and a high initial discharge capacity can be obtained at 4.3 V charging, which is one of the objects of the present invention. Difficult and not preferred. As the carbonaceous material of the negative electrode active material used in combination with the positive electrode using the lithium composite metal oxide as the active material, spherical,
Fibrous artificial graphite, granular or polygonal natural graphite obtained by coating aromatic hydrocarbons with a CVD method or coating and carbonizing the surface with pitch phenol resin, etc.
It is a single material selected from multi-structured carbon materials composed of spherical, granular, and polygonal artificial graphites and coke, or a mixture of two or more types. Pulverized polygonal and granular natural graphite, spherical, fibrous, granular and polygonal artificial graphite, coke and carbides of organic polymer materials can also be used together to the extent that the effects of the present invention are not impaired. A median particle size of 5 to 30 μm is preferred. Particularly preferred are selected from fibrous artificial graphite, natural graphite, multi-structured carbonaceous material obtained by coating artificial hydrocarbon with aromatic hydrocarbon by CVD method, or coating and carbonizing pitch etc. on the surface, coke. It is preferable to use a single particle or a mixture thereof, and to simultaneously increase the safety and the capacity of the battery, to have a median particle diameter in the range of 13 to 30 μm.

The positive electrode used in the present invention comprises 88 to 96% by weight of a mixture of the above (A) and (B) with graphite powder,
3 to 6% by weight of a conductive auxiliary such as acetylene black and polyvinylidene fluoride (PVDF), a terpolymer of propylene, vinylidene fluoride and tetrafluoroethylene, and a ternary copolymer of vinylidene fluoride, hexafluoropropylene and tetrafluoroethylene Copolymers, terpolymers of ethylene, propylene and ethylidene norbornene (EPDM),
Carboxy-modified styrene-butadiene copolymer, carboxy-modified hydrogenated styrene-butadiene copolymer, carboxymethyl cellulose, modified carboxy-modified polyacrylate, carboxy-modified polymethacrylate, ethylene-tetrafluoroethylene copolymer, polytetrafluoro Binder 1 such as ethylene (PTFE)
Coating and drying an organic solvent dispersion or an aqueous dispersion comprising up to 6% by weight on degreased aluminum foil (thickness: 10 to 20 μm) or aluminum that has been opened by laser, punching, electrolytic corrosion, or acid treatment; If necessary, it is pressed (pressurized) to increase the density. Preferably, 88 to 92% by weight of a mixture of the above (A) and (B), 4 to 6% by weight of graphite powder, and polyvinylidene fluoride (PVD)
F), from a terpolymer of propylene, vinylidene fluoride and tetrafluoroethylene, and a binder of 3 to 6% by weight selected from a terpolymer of vinylidene fluoride, hexafluoropropylene and tetrafluoroethylene. The resulting organic solvent dispersion is applied to a degreased aluminum foil or aluminum perforated by acid treatment, dried, and pressed (pressurized) to a high density.

The negative electrode used to face the positive electrode of the present invention may be a degreased rolled copper foil, an electrolytic copper foil (7 to 16 μm), a laser, a punch, an electrolytic corrosion, an acid treatment, a copper fine powder sintering and rolling. And copper at least one selected from the carbonaceous materials. 88 to 98% by weight of at least one of the carbonaceous materials is polyvinylidene fluoride (P)
VDF), a terpolymer of propylene, vinylidene fluoride and tetrafluoroethylene, a terpolymer of ethylene, propylene and ethylidene norbornene (EPDM),
Organic solvent dispersion containing 2 to 12% by weight of a binder such as carboxy-modified styrene-butadiene copolymer, carboxy-modified hydrogenated styrene-butadiene copolymer, carboxymethylcellulose, modified carboxy-modified polyacrylic acid ester, and carboxy-modified polymethacrylic acid ester A liquid or an aqueous dispersion is prepared, applied and dried, and if necessary, pressed (pressurized) to obtain a high density. Further, as long as the safety of the battery is not impaired, tin, silicon, boron and the like can be contained in the carbonaceous material. Preferably, 88 to 92% by weight of the carbonaceous material is polyvinylidene fluoride (P).
VDF), a binder of any of terpolymers of propylene, vinylidene fluoride and tetrafluoroethylene 8
An organic solvent dispersion containing 12% by weight or 96-98% by weight of the carbonaceous material is applied and dried as an aqueous dispersion comprising carboxymethyl cellulose and carboxy-modified styrene-butadiene copolymer, and pressed (pressurized). This is a high density.

The electrolyte used in the present invention contains, as an aprotic organic solvent, dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, propylene carbonate, ethylene carbonate,
Carbonates such as ethylidene carbonate, lactones such as γ-butyrolactone and ε-caprolactone, esters such as methyl formate, ethyl formate, methyl acetate and ethyl acetate, 1,2-dimethoxymethane and 1,2-diethoxy A mixture of one or more of ethers such as methane, 1,2-diethoxyethane and diglyme, nitriles such as acetonitrile and propionitrile, and heterocyclic compounds containing sulfur and / or nitrogen. Can be used. As the electrolyte, LiPF ₆ , LiB
F ₄ , (CF ₃ SO ₂ ) ₂ NLi, (CF ₃ SO ₂ ) ₂
Any one of lithium salts such as CLi or a mixture of two or more thereof can be used.

The separator used in the present invention includes a polyethylene microporous membrane, a polypropylene microporous membrane, a polyvinylidene fluoride microporous membrane, a partially crosslinked polyacrylonitrile membrane,
A crosslinked polyacrylic acid ester membrane, a microporous membrane of a propylene-vinylidene fluoride-tetrafluoroethylene terpolymer supported on ultrafine cellulose fiber paper, and the like can be used.

The positive electrode of the present invention and the negative electrode face each other with the separator interposed therebetween, spirally wound, placed in a cylindrical can, injected with the electrolytic solution, and sealed. Alternatively, the separator is wound in an elliptical or elliptical shape, or the positive electrode and the negative electrode are laminated with the separator, placed in a square can or an oblong can, and the electrolyte is injected and sealed. Furthermore, the above-mentioned elliptical winding, oval winding, laminate, the inner layer is a polyethylene or polypropylene film, the intermediate layer is aluminum foil,
The electrolyte solution can be injected into the laminate film whose surface layer is made of a nylon or polyester film and sealed. By changing the number of windings or the number of laminations, it is also possible to form a thin sheet battery. A preferable operating voltage range in which repeated charging and discharging can be performed is from 4.30 V to
It is also possible to charge with a conventional charger controlled in the range of 3.00V but at an upper voltage limit of 4.20V to 4.10V per cell.

EXAMPLES The present invention will be described in detail below with reference to examples and comparative examples, but the scope of the present invention is not limited to these examples.

Unless otherwise specified, the battery capacity is 4
Charge to 4.30V at 00mA, hold for another 3 hours,
This is the battery discharge capacity (A) when discharging to 3.00 V after resting for 30 minutes. Next, at a current of 400 mA, a battery voltage of 4.
After charging to 10 V, store at 23 ° C. for 1 week, charge again to a battery voltage of 4.30 V, hold at 4.30 V for 3 hours, rest for 30 minutes, and discharge to 3.00 V after discharge Thereafter, charging and discharging are repeated with reference to (B), the battery discharge capacity is measured, and the percentage of the battery discharge capacity at the 100th cycle with respect to the battery discharge capacity (B) is the capacity retention rate. This capacity retention is a measure of the cycle life of the battery.

The composition analysis shows that for the lithium content,
In the atomic absorption method, the content of other elements is determined by an atomic emission method (ICP method, Inductively-coupled method).
d-plasma method). Obtained as a molar ratio, the valence of each element is calculated by adding lithium to +1,
Assuming that aluminum, cobalt, and manganese are +3, the oxygen content is determined as the oxygen content which is electronically neutralized (becomes 0) with -2. Oxygen in the composition formula to be displayed is changed to O ₂ to O ₄ .

Example 1 As an active material of a lithium composite metal oxide of a positive electrode, a manganese spinel compound (A) was Li _1.04 Co _0.05 Mn _1.95 O ₄ ,
5.67 grams of modified lithium cobaltate (B) is Li
_1.01 Mn _0.0015 Fe _0.0010 Co
_0.9975 O ₂ , 6.93 grams were applied to a 15 micron thick aluminum foil using 0.803 grams of graphite as a conductive aid and 0.625 grams of polyvinylidene fluoride as a binder and pressed. 55.5mm width positive electrode sheet with lead tab and pulverized, refined and squeezed natural graphite using toluene
Multi-structure carbon material (GDA-2-K manufactured by Mitsui Mining Co., Ltd.) coated with a carbonaceous material equivalent to 18% by weight by VD method and milled graphite fiber (Melbron Milled FM manufactured by Petka)
Using a mixed powder of 5.32 g (weight ratio of 80:20) and 0.691 g of polyvinylidene fluoride as a binder, the mixture was applied to a 10-micron-thick rolled copper foil which had been degreased, and pressed. 45 mol% of propylene, 50 mol% of tetrafluoroethylene using ethyl acetate as a solvent for the base paper 1 of regenerated cellulose fibers beaten between the negative electrode sheet with a lead tab having a width of 57.0 mm and
70% by weight of a terpolymer of 5 mol% of vinylidene fluoride
And propylene 25 mol%, tetrafluoroethylene 40
The mixture is impregnated with 30% by weight of a terpolymer of 35% by mole of vinylidene fluoride at a ratio of 0.2% of a mixture of 30% by weight, and is dried. Spirally wound through a film that becomes a conductor,
After being placed in a cylindrical can with an inner diameter of 17.5 mm, the negative electrode lead tab was spot-welded to the bottom of the can, and the positive electrode lead tab was spot-welded to an aluminum rupture disk, which is a component of the can lid assembly of the positive electrode terminal, and after beading,
The whole is dried at 110 ° C. under a reduced pressure of 0.1 mmHg for 8 hours. Cool in a dry room with a dew point of -55 ° C, return to normal pressure, and divide 5.1 g of a mixed solvent (1: 2: 2 volume ratio) of 1M LiPF ₆ consisting of ethylene carbonate, dimethyl carbonate, and ethyl methyl carbonate as an electrolytic solution. Then, the pressure is reduced during the addition to promote the impregnation of the electrolytic solution while defoaming. Then, seal with a caulking machine. Table 1 shows the measurement results.

Example 2 As an active material of a lithium composite metal oxide for a positive electrode, a manganese spinel compound (A) was Li _1.04 Co _0.05 Mn _1.95 O ₄ ,
1.28 grams of modified lithium cobaltate (B) is Li
_1.01 Mn _0.001 Fe _0.001 Co _0.998
An O _2, is applied to an aluminum foil of 15 microns thickness using a polyvinylidene fluoride 0.581 g graphite 0.786 g and a binder of the conductive aid 11.52 g, width is pressed 55 .5m
1 m of positive electrode sheet with a lead tab and pulverized, refined and squeezed natural graphite by toluene using toluene
Mixed powder (80:20) of multi-structure carbon material (GDA-2-K manufactured by Mitsui Mining Co., Ltd.) coated with a carbonaceous material equivalent to 8% by weight and milled graphite fiber (Melbron Milled FM14 manufactured by Petka) A weight ratio of 5.33 g and 0.692 g of polyvinylidene fluoride binder are applied to a 10-micron-thick rolled copper foil that has been degreased and pressed, and a negative electrode with a lead tab having a width of 57.0 mm is pressed. A terpolymer of 45 mol% of propylene, 50 mol% of tetrafluoroethylene, and 5 mol% of vinylidene fluoride was mixed with the base paper 1 of regenerated cellulose fibers beaten between the sheet and ethyl acetate as a solvent. 30% by weight of a terpolymer of 25% by weight, 25% by mole of propylene, 40% by mole of tetrafluoroethylene and 35% by mole of vinylidene fluoride
23 obtained by impregnation at a ratio of 0.2 of a mixture of
It is spirally wound through a film serving as a lithium ion conductor having a thickness of 5 μm and a thickness of 59.5 mm.
After placing in a 5 mm cylindrical can, the negative electrode lead tab was spot-welded to the bottom of the can, and the positive electrode lead tab was spot-welded to an aluminum rupture disk, which is a component of the can lid assembly of the positive electrode terminal. And dried under reduced pressure of 0.1 mmHg for 8 hours. Cool in a dry room with a dew point of -55 ° C, return to normal pressure, and divide 5.1 g of a mixed solvent (1: 2: 2 volume ratio) of 1M LiPF ₆ consisting of ethylene carbonate, dimethyl carbonate, and ethyl methyl carbonate as an electrolytic solution. Then, the pressure is reduced during the addition to promote the impregnation of the electrolytic solution while defoaming. Then, seal with a caulking machine. Table 1 shows the measurement results.

Example 3 As an active material of a lithium composite metal oxide for a positive electrode, a manganese spinel compound (A) is Li _1.04 Co _0.05 Mn _1.95 O ₄ ,
9.76 g of modified lithium cobaltate (B) is Li
_1.01 Mn _0.0015 Fe _0.0010 Co
_0.9975 O ₂ , 2.44 grams were applied to a 15 micron thick aluminum foil using 0.806 grams of graphite as a conductive aid and 0.576 grams of polyvinylidene fluoride as a binder and pressed. 55.5mm width positive electrode sheet with lead tab and pulverized, refined and squeezed natural graphite using toluene
Multi-structure carbon material (GDA-2-K manufactured by Mitsui Mining Co., Ltd.) coated with a carbonaceous material equivalent to 18% by weight by VD method and milled graphite fiber (Melbron Milled FM manufactured by Petka)
14) and 5.30 g of a mixed powder (weight ratio of 80:20) and 0.576 g of polyvinylidene fluoride binder were applied to a rolled copper foil having a thickness of 10 μm and degreased, and pressed. 45 mol% of propylene, 50 mol% of tetrafluoroethylene using ethyl acetate as a solvent for the base paper 1 of regenerated cellulose fibers beaten between the negative electrode sheet with a lead tab having a width of 57.0 mm and
70% by weight of a terpolymer of 5 mol% of vinylidene fluoride
And propylene 25 mol%, tetrafluoroethylene 40
The mixture is impregnated with 30% by weight of a terpolymer of 35% by mole of vinylidene fluoride at a ratio of 0.2% of a mixture of 30% by weight, and is dried. Spirally wound through a film that becomes a conductor,
After being placed in a cylindrical can with an inner diameter of 17.5 mm, the negative electrode lead tab was spot-welded to the aluminum bottom of the can, and the positive electrode lead tab was spot-welded to an aluminum rupture disk, which is a component of the can lid assembly of the positive electrode terminal.
The whole is dried at 110 ° C. under a reduced pressure of 0.1 mmHg for 8 hours. Cool in a dry room with a dew point of -55 ° C, return to normal pressure, and divide 5.1 g of a mixed solvent (1: 2: 2 volume ratio) of 1M LiPF ₆ consisting of ethylene carbonate, dimethyl carbonate, and ethyl methyl carbonate as an electrolytic solution. Then, the pressure is reduced during the addition to promote the impregnation of the electrolytic solution while defoaming. Then, seal with a caulking machine. Table 1 shows the measurement results.

Example 4 As the active material of the lithium composite metal oxide for the positive electrode, manganese spinel compound (A) was Li _1.04 Co _0.02 Al _0.03 Mn _1.95 O
A _4, 6.82 grams of modified lithium cobaltate (B) is _Li 1.01 _{Mn 0.0015} Fe
_0.0010 Al _0.0005 Co _0.9975 O ₂ , 5.58 grams of graphite 0.7 as a conductive additive
99g and binder polyvinylidene fluoride 0.6
A 30-gram, 15-micron-thick aluminum foil coated and pressed on a 155.5-mm-wide positive-electrode sheet with lead tabs and 18 wt. %
Powder (80:20 weight ratio) of a multi-structure carbon material (GDA-2-K manufactured by Mitsui Mining Co., Ltd.) coated with a carbonaceous material corresponding to the above and milled graphite fiber (Melbron milled FM14 manufactured by Petka) 5.25 grams and 0.682 grams of polyvinylidene fluoride binder were applied to a 10 micron thick rolled copper foil that had been degreased,
45 mol% of propylene was obtained by using ethyl acetate as a solvent for the base paper 1 of regenerated cellulose fibers beaten between a pressed negative electrode sheet with a lead tab having a width of 57.0 mm and 57.0 mm.
70% by weight of a terpolymer of 50% by mole of tetrafluoroethylene and 5% by mole of vinylidene fluoride and 25% of propylene
A terpolymer of 40 mol%, 40 mol% of tetrafluoroethylene and 35 mol% of vinylidene fluoride is impregnated with a mixture of 0.2% of 30% by weight and dried to obtain a width of 23 μm in thickness. It is spirally wound through a 59.5 mm film serving as a lithium ion conductor, and has an inner diameter of 17.5 mm.
The negative electrode lead tab was placed on the bottom of the can, and the positive electrode lead tab was spot-welded to an aluminum rupture disk, which is a component of the can lid assembly of the positive electrode terminal.
Dry at 0.1 ° C. under a reduced pressure of 0.1 mmHg for 8 hours. Cool in a dry room with a dew point of -55 ° C, return to normal pressure, and divide 5.1 g of a mixed solvent (1: 2: 2 volume ratio) of 1M LiPF ₆ consisting of ethylene carbonate, dimethyl carbonate, and ethyl methyl carbonate as an electrolytic solution. Then, the pressure is reduced during the addition to promote the impregnation of the electrolytic solution while defoaming. Then, seal with a caulking machine. Table 1 shows the measurement results.

Comparative Example 1 As an active material of the lithium composite metal oxide of the positive electrode, the manganese spinel compound (A) was Li _1.06 Mn _2.00 O ₄ , 5.58 g of modified lithium cobalt oxide. (B) is Li _1.03 CoO
₂ , 6.82 grams, 0.790 grams of graphite as a conductive aid and 0.615 grams of polyvinylidene fluoride as a binder, are applied to a 15 micron thick aluminum foil and press pressed 55. 5mm
Of positive electrode sheet with lead tab and natural graphite pulverized, refined and squeezed by toluene using toluene
A mixed powder (80:20 weight) of a multi-structure carbon material (GDA-2-K manufactured by Mitsui Mining Co., Ltd.) coated with a carbonaceous material corresponding to the weight% and milled graphite fiber (Melbron milled FM14 manufactured by Petka) Ratio) 5.38 g of a negative electrode sheet with a lead tab having a width of 57.0 mm applied to a rolled copper foil having a thickness of 10 μm and pressed using a binder of 0.699 g of polyvinylidene fluoride, which is degreased. Recycled cellulose fiber base paper 1 beaten between
70% by weight of a terpolymer of 45 mol% of propylene, 50 mol% of tetrafluoroethylene and 5 mol% of vinylidene fluoride, 25 mol% of propylene and 40 mol% of tetrafluoroethylene using ethyl acetate as a solvent A terpolymer of 35 mol% of vinylidene fluoride in an amount of 0.2% of a mixture of 30% by weight, and a lithium ion conductor having a thickness of 23 microns and a width of 59.5 mm, obtained by drying; Spirally wound through a membrane having an inner diameter of 17.5.
mm, and the negative electrode lead tab was spot-welded to the bottom of the can, and the positive electrode lead tab was spot-welded to an aluminum rupture disk, which is a component of the can lid assembly of the positive electrode terminal.
Dry at 10 ° C. under a reduced pressure of 0.1 mmHg for 8 hours.
Cool in a dry room with a dew point of -55 ° C, return to normal pressure, and divide 5.1 g of a mixed solvent (1: 2: 2 volume ratio) of 1M LiPF ₆ consisting of ethylene carbonate, dimethyl carbonate, and ethyl methyl carbonate as an electrolytic solution. Then, the pressure is reduced during the addition to promote the impregnation of the electrolytic solution while defoaming. Then, seal with a caulking machine. Table 1 shows the measurement results.

Comparative Example 2 As an active material of a lithium composite metal oxide for a positive electrode, a manganese spinel compound (A) was Li _1.01 Al _0.03 Mn _1.97 O ₄ ,
9.60 g of modified lithium cobalt oxide (B) is Li
_1.01 Mn _0.05 Co _0.95 O ₂ , 2.4
Was mixed with 0.793 g of graphite as a conductive additive, and 0.645 g of polyvinylidene fluoride as a binder was mixed.
55.5 mm width of a positive electrode sheet with a lead tab, 5.10 g of milled graphite fiber (Pelka Melblon Milled FM14), and a binder polyfoil coated with 15 g of aluminum foil having a thickness of 15 μm. 0.567 grams of vinylidene bromide was applied to a 10 micron thick rolled copper foil that had been degreased, and was beaten between a pressed 57.0 mm wide negative electrode sheet with lead tabs and pressed. Base paper 1
70% by weight of a terpolymer of 45 mol% of propylene, 50 mol% of tetrafluoroethylene and 5 mol% of vinylidene fluoride, 25 mol% of propylene and 40 mol% of tetrafluoroethylene using ethyl acetate as a solvent A terpolymer of 35 mol% of vinylidene fluoride in an amount of 0.2% of a mixture of 30% by weight, and a lithium ion conductor having a thickness of 23 microns and a width of 59.5 mm, obtained by drying; Spirally wound through a membrane having an inner diameter of 17.5.
mm, and the negative electrode lead tab was spot-welded to the bottom of the can and the positive electrode lead tab was spot-welded to an aluminum rupture disk, which is a component of the can lid assembly of the positive electrode terminal.
Dry at 10 ° C. under a reduced pressure of 0.1 mmHg for 8 hours.
Cool in a dry room at a dew point of -55 ° C, return to normal pressure, and divide 5.1 g of a mixed solvent (1: 2: 2 volume ratio) of 1M LiPF ₆ consisting of ethylene carbonate, dimethyl carbonate, and ethyl methyl carbonate as an electrolytic solution. Then, the pressure is reduced during the addition, and the impregnation of the electrolytic solution is promoted while defoaming. Then, seal with a caulking machine. Table 1 shows the measurement results.

Comparative Example 3 As the active material of the lithium composite metal oxide of the positive electrode, the manganese spinel compound (A) was Li _1.01 Al _0.03 Mn _1.97 O ₄ ,
0.62 g and modified lithium cobaltate (B) are Li
_1.01 Mn _0.05 Co _0.95 O ₂ and 1.1
Eight grams were applied to a 15 micron thick aluminum foil using 0.788 grams of graphite as a conductive additive and 0.649 grams of polyvinylidene fluoride as a binder, and a 55.5 mm wide positive electrode sheet with a lead tab was pressed. 4. Natural graphite pulverized and refined
15 grams and binder polyvinylidene fluoride 0.6
Width 57.0 is applied and pressed onto a 10 micron thick rolled copper foil that has been degreased using 69 grams.
The regenerated cellulose fiber base paper 1 beaten between a negative electrode sheet with a lead tab having a thickness of 45 mm and a solvent of ethyl acetate was used.
Mol%, vinylidene fluoride 5 mol% terpolymer
A terpolymer of 0% by weight, 25% by mole of propylene, 40% by mole of tetrafluoroethylene and 35% by mole of vinylidene fluoride was impregnated at a ratio of 0.2% of a 30% by weight mixture and dried to obtain 23. It is spirally wound through a micron-thick 59.5 mm-wide film to be a lithium ion conductor, placed in a cylindrical can with an inner diameter of 17.5 mm, the negative electrode lead tab on the bottom of the can, and the positive electrode lead tab on the positive terminal can. After spot welding to an aluminum rupture disk, which is one component of the lid assembly, and beading, the whole is dried at 110 ° C. under a reduced pressure of 0.1 mmHg for 8 hours. Cool in a dry room at a dew point of -55 ° C, return to normal pressure, and use a mixed solvent of 1M LiPF ₆ consisting of ethylene carbonate, dimethyl carbonate, and ethyl methyl carbonate (1: 2: 2 volume ratio) as an electrolyte.
5.1 grams are divided and the pressure is reduced during the addition to promote the impregnation of the electrolyte while defoaming. Then, seal with a caulking machine. Table 1 shows the measurement results.

[0023]

[Table 1]

[Effects of the Invention] According to the present invention, a specific manganese spinel and a specific modified lithium cobaltate are independently prepared, and a specific compounding ratio is used to utilize other transition metals which are more abundant as resources. Thus, the cobalt ratio can be reduced. New Li-Mn-Co
By finding a positive electrode of the system and combining it with a specific negative electrode active material, it is possible to improve the overcharge resistance at 4.2 V or more, which is a disadvantage of conventional lithium ion secondary batteries, and to improve the battery capacity. This is a non-aqueous secondary battery capable of improving safety and improving service life by improving overcharge resistance while maintaining high capacity. Due to resource constraints, the ratio of expensive cobalt can be reduced, so that it can cope with a sudden increase in demand.

Claims (2)

[Claims] 1. A non-aqueous secondary battery comprising a positive electrode using a lithium composite metal oxide as an active material and a negative electrode using a carbonaceous material as an active material, wherein the positive electrode has a general formula of Li _a Co _b Al _c Mn.
_(2- bc ₎ O ₄ (where a, b, and c are respectively 1.03 ≦ a ≦ 1.06, 0.015 ≦ b ≦ 0.05,
Represents the number 0 ≦ c ≦ 0.05. ) Manganese spinel compound is (A) and the general formula _{Li a Mn b Fe c Al d} C
o _(1-bcd) O ₂ (where a, b, c, and d are
1.00 ≦ a ≦ 1.03, 0.00005 ≦ b
≦ 0.009, 0.00005 ≦ c ≦ 0.005, 0 ≦
represents a number d ≦ 0.01. (A) is 10% by weight or more and 80% by weight or less and (B) is 90% by weight or more and 20% by weight or more. Next battery. 2. A non-aqueous secondary battery comprising a positive electrode using a lithium composite metal oxide as an active material and a negative electrode using a carbonaceous material as an active material, wherein the negative electrode is a spherical or fibrous artificial graphite or an aromatic. Multi-structure carbon material composed of granular, polygonal natural graphite, spherical, granular, and polygonal artificial graphite obtained by coating hydrocarbons by CVD method or coating and carbonizing the surface with pitch phenol resin, etc., coke The non-aqueous secondary battery according to claim 1, wherein the non-aqueous secondary battery is a single battery selected from the group consisting of a mixture of two or more.