JPH09213339A - Non-aqueous secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a non-aqueous secondary battery having excellent charge/ discharge cyclic characteristics and a high producibility by forming an electricity collector of a positive electrode from a foil of aluminum-based metal or alloy which shows specific values of ruptural strength and elongation after a high- temp. heat treatment. SOLUTION: A non-aqueous secondary battery concerned is composed of a positive electrode and negative electrode containing material capable of occluding and releasing lithium reversibly, a non-aqueous electrolyte containing lithium salt, and a separator, wherein the electricity collector of a positive electrode sheet is made of an aluminum-based metal. The tensile strength after a 30-min heat treatment at a temp. of 23 deg.C should range between 7 and 40kg/mm<2> , and the ruptural elongation range between 1 and 15%.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-aqueous secondary battery having improved charge / discharge cycle life and improved manufacturing stability. In particular, the current collector of the positive electrode has mechanical properties after heat treatment. The present invention relates to a good non-aqueous secondary battery which is a metal mainly composed of aluminum.

[0002]

2. Description of the Related Art It is known to use an aluminum alloy as a current collector of a positive electrode for a non-aqueous secondary battery. This current collector needs to be stable against the electrochemical reaction in the battery, and is required to have sufficient mechanical strength. Japanese Patent Laid-Open Publication No. 2-204976 describes the use of various aluminum alloys. Further, JP-A-6-267542 describes the use of high-purity aluminum. These propose an alloy composition in which the current collector is unlikely to corrode due to a chemical reaction in the battery. The degree of improvement in the cycle performance by the current collector described in these is insufficient.

[0003]

An object of the present invention is to obtain a non-aqueous secondary battery having improved charge / discharge cycle characteristics, high discharge voltage, high capacity and high productivity.

[0004]

The lithium of the present invention is reversible.
Positive electrode and negative electrode containing a material that can be occluded and released, lithium
Non-aqueous secondary electricity consisting of salt-containing non-aqueous electrolyte and separator
In the pond, the collector of the positive electrode sheet is made of aluminum.
Made of metal as the main component and at a temperature of 230 ° C for 30 minutes
Tensile strength after heat treatment for 7kg / mm^TwoAbove
40 kg / mm ^TwoAnd the elongation at break is 1% or more
Can be obtained by non-aqueous secondary battery which is 15% or less
Was.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below, but the present invention is not limited thereto. 1. In a non-aqueous secondary battery consisting of a positive electrode and a negative electrode containing a material capable of reversibly inserting and extracting lithium, a non-aqueous electrolyte containing a lithium salt, and a separator, the current collector of the positive electrode sheet is made of a metal mainly composed of aluminum. , And 23
Tensile strength after heat treatment at 0 ° C for 30 minutes is 7
Kg / mm ² or more is at 40 Kg / mm ² or less, and a nonaqueous secondary battery breaking elongation is 15% or less than 1%. 2. 3 when the tensile strength of the current collector is 8 kg / mm ² or more
0 kg / mm ² or less and elongation at break of 2% or more 1
The non-aqueous secondary battery according to 1 above, which is 5% or less. 3. 1 wherein the negative electrode material is an amorphous oxide and / or chalcogenide mainly composed of Sn
Alternatively, the non-aqueous secondary battery described in 2.

[0006] 4. The negative electrode material is represented by the general formula (1) SnM ¹ _a O _t general formula (1) (wherein M ¹ is Al, B, P, Si, Ge, a group 1 element, a group 2 element, a group 2 element of the periodic table, It represents two or more elements selected from Group 3 elements and halogen elements, a represents a number of 0.2 or more and 2 or less, and t represents a number of 1 or more and 6 or less). The non-aqueous secondary battery according to any one of 1 to 3 above. 5. The negative electrode material has the general formula (2) Sn _x T _1-x M ¹ _a O _t general formula (2) (wherein T represents a transition metal metal, and V, Ti, Fe, M
n, Co, Ni, Zn, W, and Mo. x represents a number of 0.1 or more and 0.9 or less. M ¹ , a, and t are represented by the general formula (1)), and the non-aqueous secondary battery according to any one of 1 to 3 above. 6. The negative electrode material is represented by the general formula (3) SnM ² _b O _t general formula (3) (wherein M ² is Al, B, P, Ge, Group 1 element, Group 2 element, Group 3 element of the periodic table). And 2 or more elements selected from an element and a halogen element, b is a number of 0.2 or more and 2 or less, and t is a number of 1 or more and 6 or less) The non-aqueous secondary battery according to item 4.

7. The negative electrode material is represented by the general formula (4) SnM ³ _c M ⁴ _d O _t general formula (4) (wherein M ³ is at least one of Al, B, P and Ge, and M ⁴ is the periodic table 1 Represents at least one element selected from Group 3 elements, Group 2 elements, Group 3 elements, and halogen elements, and c is 0.2.
Is a number of 2 or more and 2 or less, d is a number of 0.01 or more and 1 or less,
0.2 <c + d <2, t represents a number of 1 or more and 6 or less), The non-aqueous secondary battery according to item 6 above.

The technique of the present invention will be described in detail below. In the present invention, a metal mainly containing aluminum is used for the current collector of the positive electrode. Preferably the tensile strength after heat treatment for 30 minutes at a temperature of 230 ° C. The current collector is 40 Kg / mm ² or less at 7 Kg / mm ² or more, 8 Kg /
mm and more preferably 30 Kg / mm ² or less ² or more, 1
0 kg / mm ² or more at 30 Kg / mm ² or less being more preferred. Further, the breaking elongation is preferably 1% or more and 15% or less, more preferably 2% or more and 15% or less, and particularly preferably 2% or more and 13% or less.

The composition of the current collector may be any metal or alloy mainly composed of aluminum. For example, "Aluminum Handbook (4th Edition)" published by Japan Light Metal Association.
Nos. 202 to 213 and 217 to 218 can be preferably used. Particularly preferred are those in the 1000 series and those containing 0.5% or more and 3% or less of iron. The thickness of the current collector is preferably 5 μm or more and 50 μm or less, more preferably 8 μm or more and 35 μm or less. The surface may be a glossy surface or a non-glossy surface, and the surface roughness is a center line average roughness according to JIS B0601 of 0.0.
5 to 3.0 μm is preferable, and 0.07 to 1.0 μm is more preferable.

The negative electrode material preferably used in the present invention is
Alkali metal or its alloys, especially lithium metal and its alloys, carbon materials such as black smoke, non-black smoke carbon materials (especially mesophase carbon), metalloids and / or metal oxides or chalcogenides, but metalloids And / or metal oxides or chalcogenides are particularly preferred. As an element forming an oxide or a chalcogenide, a transition metal, a metal of Group 13 to 15 of the periodic table, or a metalloid element is preferable.

As the transition metal compound, V, Ti,
A single or composite oxide of Fe, Mn, Co, Ni, Zn, W, and Mo, or a chalcogenide is preferable. Further preferred compounds of JP-A 6-44,972 No. claimed _{Li p Co q V 1-q} O r ( wherein p = 0.1 to 2.5,
q = 0 to 1, z = 1.3 to 4.5).

Compounds of metals other than transition metals and semimetals
For example, elements of Groups 13 to 15 of the periodic table, Al, Ga,
Si, Sn, Ge, Pb, Sb, Bi alone or
Chalcogenide, an oxide consisting of a combination of two or more of these
Nido is selected. For example, Ga_TwoO_Three, SiO, Ge
O, GeO_Two, SnO, SnO_Two, SnSiO_Three, Pb
O, PbO_Two, Pb_TwoO_Three, Pb_TwoO_Four, Pb_ThreeO_Four,
Sb_TwoO_Three, Sb_TwoO_Four, Sb_TwoO_Five, Bi_TwoO_Three, B
i_TwoO_Four, Bi_TwoO_Five, SnSiO _Three, GeS, GeS
_Two, SnS, SnS_Two, PbS, PbS_Two, Sb
_TwoS_Three, Sb_TwoS_Five, SnSiS_ThreeAre preferred. or
These are complex oxides with lithium oxide, such as Li_Two
GeO_Three, Li_TwoSnO_TwoIt may be.

The above-mentioned complex chalcogen compound and complex oxide are preferably mainly amorphous when incorporated in a battery. The term “amorphous” as used herein refers to a substance having a broad scattering band having a peak at 20 ° to 40 ° in 2θ value by X-ray diffraction using CuKα ray, and having a crystalline diffraction line. Is also good. Preferably, the strongest intensity among the crystalline diffraction lines observed at 40 ° to 70 ° in 2θ value is 2θ.
It is preferably 500 times or less, more preferably 100 times or less, particularly preferably 5 times or less, and most preferably 5 times or less, as high as the diffraction line intensity at the apex of the broad scattering band seen in a value of 20 ° to 40 °. It is preferable that it has no crystalline diffraction line.

The above complex chalcogen compound and complex oxide are complex compounds composed of transition metals and elements of groups 15 to 15 of the periodic table, and include B, Al, Ga, In, Tl, Si,
A complex chalcogen compound and a complex oxide mainly composed of two or more elements among Ge, Sn, Pb, P, As, Sb, and Bi are more preferable. More preferably, it is a composite oxide.
Particularly preferred is a composite oxide mainly composed of two or more elements among B, Al, Si, Ge, Sn, and P. These complex chalcogen compounds and complex oxides may contain a Group 1 to Group 3 element of the periodic table or a halogen element mainly to modify the amorphous structure. Further, it may contain a transition metal.

Among the above-mentioned negative electrode materials, an amorphous composite oxide containing tin as a main component is preferable and represented by the following general formula (1) or (2). SNM ¹ _a O _t in the general formula (1), M ¹ is Al, B, P, Si, Ge, Periodic Table 1
A represents a number of 0.2 or more and 2 or less, and t represents a number of 1 or more and 6 or less. .

Sn _x T _1-x M ¹ _a O _t General formula (2) In the formula, T represents a transition metal metal, and V, Ti, Fe, M
n, Co, Ni, Zn, W, and Mo. x represents a number of 0.1 or more and 0.9 or less. M ¹ , a, and t are the same as those in the general formula (1).

Among the compounds of general formula (1), the following compounds of general formula (3) are more preferred. SNM ² _b O _t formula (3) wherein, M ² is Al, B, P, Ge, periodic table Group 1 element, group 2 element, a Group 3 element, two or more selected from halogen B represents a number of 0.2 or more and 2 or less, and t represents a number of 1 or more and 6 or less.

Among the compounds of general formula (3), the following compounds of general formula (4) are more preferable. SnM ³ _c M ⁴ _d O _t formula (4) wherein, M ³ is Al, B, P, at least one Ge,
M ⁴ is a group 1 element, a group 2 element, a group 3 element of the periodic table,
Represents at least one kind of halogen element, c is a number of 0.2 or more and 2 or less, d is a number of 0.01 or more and 1 or less,
0.2 <c + d <2, t represents a number from 1 to 6.

The amorphous composite oxide and / or chalcogenide of the present invention can be produced by the general formula (1) in the firing method.
It is preferable to obtain an amorphous composite oxide by thoroughly mixing the oxides or compounds of the elements described in 1. and then calcining.

The firing conditions are preferably a heating rate of 5 ° C. or more and 200 ° C. or less per minute, and a firing temperature of 500 ° C. or more and 1500 ° C. or less. The firing time is preferably 1 hour or more and 100 hours or less, and the temperature lowering rate is preferably 2 ° C. or more and 10 ⁷ ° C. or less per minute.

The temperature rising rate in the present invention is from "50% of the firing temperature (displayed in ° C)" to "80" of the firing temperature (displayed in ° C).
% ", Which is the average rate of temperature increase until the temperature reaches"% ", and the term" cooling rate "in the present invention refers to" 80% of the firing temperature (° C) ".
This is the average rate of temperature decrease from the point when the temperature reaches “50% of the firing temperature (expressed in ° C.)”.

The firing gas atmosphere is preferably an atmosphere having an oxygen content of 5% by volume or less and 0.0001% by volume or more,
More preferably, it is an inert gas atmosphere. Examples of the inert gas include nitrogen, argon, helium, krypton, xenon, and the like. The most preferred inert gas is pure argon.

The average particle size of the compound represented by the present invention is preferably 0.1 to 60 μm, more preferably 1 to 20 μm. Examples of preferable negative electrode materials are shown below. 1. SnAl _0.4 B _0.4 P _0.4 Cs _0.05 K _0.05 O _3.25 2. SnAl _0.4 B _0.4 P _0.4 Cs _0.05 K _0.05 Ca _0.1
O _3.35 3. SnAl _0.4 B _0.5 P _0.5 Na _0.2 Cs _0.05 K _0.1
Ca _0.05 O _3.08 4. SnAl _0.4 B _0.3 P _0.5 Rb _0.2 Cs _0.1 O _2.95 5. SnAl _0.4 B _0.5 P _0.5 Cs _0.1 K _0.1 Ge _0.1
O _3.85 6. SnAl _0.4 B _0.5 P _0.5 K _0.1 Ge _0.05 O _3.75 7. SnAl _0.4 B _0.5 P _0.5 K _0.1 Mg _0.1 Ge _0.02
O _3.73 8. SnAl _0.4 B _0.8 P _0.4 O _3.8 9. SnAl _0.4 B _0.5 P _0.3 Ba _0.08 Mg _0.08 O _3.26 10. SnAl _0.4 B _0.4 P _0.4 Ba _0.08 K _0.05 Ca
_0.1 Ti _0.2 O _3.81

11. SnAl _0.4 B _0.4 P _0.4 Cs _0.05
K _0.05 Ca _0.1 Ti _0.2 O _3.75 12. SnAl _0.4 B _0.4 P _0.4 Cs _0.05 K _0.1 Ca
_0.05 F _0.2 O _3.22 13. SnAl _0.4 B _0.4 P _0.8 Cs _0.05 K _0.1 Ca
_0.05 F _0.2 O _4.22 14. SnSi _0.5 Al _0.2 B _0.1 P _0.1 Mg _0.1 O
_2.8 15. SnSi _0.5 Al _0.6 B _0.6 P _0.2 O _4.3 16. SnSi _0.6 Al _0.3 B _0.1 P _0.1 Ba _0.2 O
_2.95

17. Sn _0.9 Al _0.1 Mn _0.3 B _0.4 P
_0.4 Ca _0.1 Rb _0.1 O _3.4 18. Sn _0.9 Al _0.1 Fe _0.3 B _0.4 P _0.4 Ca _0.1
Rb _0.1 O _3.25 19. _{Sn 0.8 Al 0.1 Pb 0.2 Ca 0.1} P 0.9 O 4. 1 20. _{Sn 0.3 Al 0.1 Ge 0.7 Ba 0.1} P 0.9 O 4. 8 21. _{Sn 0.9 Al 0.1 Mn 0.1 Mg 0.1} P 0.9 O 3. 6 22. Sn _0.2 Al _0.1 Mn _0.8 Cs _0.1 K _0.1 Ca
_0.05 Ti _0.2 P _0.9 O _4.75

The chemical formula of the compound obtained by firing can be calculated from an inductively coupled plasma (ICP) emission spectral analysis method as a measuring method and a weight difference between powders before and after firing as a simple method.

The amount of lithium inserted into the negative electrode material of the present invention is
The amount is preferably from 50 to 700 mol%, more preferably from 100 to 600 mol%, per negative electrode material. It is preferable that the release amount be larger than the insertion amount. The method of inserting lithium is preferably an electrochemical, chemical or thermal method.

The negative electrode material of the present invention may contain various elements. For example, lanthanoid metals (Hf, T
a, W, Re, Os, Ir, Pt, Au, Hg) and various compounds that increase electron conductivity (for example, Sb, In, N
b) may be included. The amount of the compound to be added is preferably 0 to 5 mol%.

A more preferable lithium-containing transition metal oxide positive electrode material used in the present invention is a lithium compound /
Transition metal compound (Here, transition metal means Ti, V, C
It is preferable to mix and synthesize so that the total molar ratio of r, Mn, Fe, Co, Ni, Mo, and W) is 0.3 to 2.2. As a particularly preferable lithium-containing transition metal oxide positive electrode material used in the present invention, a lithium compound / transition metal compound (wherein the transition metal is at least one selected from V, Cr, Mn, Fe, Co and Ni) The total molar ratio of
It is preferable to synthesize them by mixing them to 2.2.
Particularly preferable lithium-containing transition metal oxide positive electrode material used in the present invention is Lix QOy (wherein Q is mainly at least one of Co, Mn, Ni, V, and F).
e), x = 0.02 to 2.2, y = 1.
It is preferably 4 to 3). As Q, in addition to transition metals, Al, Ga, In, Ge, Sn, Pb, Sb, B
You may mix i, Si, P, B, etc. The mixing amount is preferably 0 to 30 mol% with respect to the transition metal.

Further preferred Lithiu used in the present invention
As a positive electrode material containing a metal oxide, Lix CoO_Two,
Lix NiO_Two, Lix MnO_Two, Lix Coa Ni
_1-aO _Two, Lix Co_bV_1-bOz, Lix Co_bFe
_1-bO_Two, Lix Mn_TwoO_Four, Lix Mnc Co_2-cO
_Four, Lix Mn_cNi_2-cO_Four, Lix Mn_cV_2-cO
_Four, Lix Mn_cFe_2-cO_Four(Where x = 0.02
2.2, a = 0.1 to 0.9, b = 0.8 to 0.98,
c = 1.6 to 1.96, z = 2.01 to 2.3).
Can be Most preferred lithium containing used in the present invention
As a transition metal oxide positive electrode material, Lix CoO_Two, L
ix NiO_Two, Lix MnO_Two, Lix Co_aNi_1-a
O_Two, Lix Mn_TwoO_Four, Lix Co_bV_1-bOz (This
Here, x = 0.02 to 2.2, a = 0.1 to 0.9, b =
0.9 to 0.98, z = 2.01 to 2.3).
You. Here, the above x value is a value before the start of charging and discharging,
It increases or decreases due to charge and discharge.

The positive and negative electrodes used in the non-aqueous secondary battery of the present invention can be produced by coating the positive electrode mixture or the negative electrode mixture on a current collector or molding it into pellets. The positive electrode or negative electrode mixture may contain a conductive agent, a binder, a dispersant, a filler, an ionic conductive agent, a pressure enhancer, and various additives, respectively, in addition to the positive electrode material or the negative electrode material.

The conductive agent in the positive electrode and the negative electrode which can be used in the present invention is graphite, acetylene black, carbon black, Ketjen black, carbon fiber or metal powder, metal fiber or polyphenylene derivative, and graphite or acetylene black is particularly preferable. . The binder in the positive electrode and the negative electrode that can be used in the present invention is polyacrylic acid, carboxymethylcellulose, polytetrafluoroethylene,
Polyvinylidene fluoride, polyvinyl alcohol, starch,
Regenerated cellulose, diacetyl cellulose, hydroxypropyl cellulose, polyvinyl chloride, polyvinyl pyrrolidone, polyethylene, polypropylene, SBR, E
PDM, sulfonated EPDM, fluororubber, polybutadiene, and polyethylene oxide, with polyacrylic acid, carboxymethylcellulose, polytetrafluoroethylene, and polyvinylidene fluoride being particularly preferred.

The negative electrode sheet and the positive electrode sheet have a mixture layer containing a negative electrode material and a positive electrode material, respectively. In addition to the respective materials, the mixture layer is preferably a conductive agent, a binder, a dispersant, various inorganic salts (particularly alkali metal salts and alkaline earth salts are preferable), and organic salts (particularly alkali metal salts and alkaline earth salts). ), Solid fine particles (alumina, titanium dioxide, zirconia, carbon,
It is preferable to include metal particles). Further, the mixture layer may have a multilayer structure of two or more layers. In this case, the difference in the layer structure is the difference in the content of each material of the negative electrode and the positive electrode, the particle size, the difference in the composition of the material, the content of the conductive agent, the type of the conductive agent, the type of binder and the amount and the amount of solid fine particles Is preferred. In addition to the mixture layer, each negative electrode, a protective layer containing no positive electrode material, an intermediate layer, and an undercoat layer may be provided.

The negative electrode support or collector which can be used in the present invention is made of copper, stainless steel, nickel, titanium, or an alloy thereof, and can be in the form of foil, expanded metal, punching metal, wire mesh. Is. Copper foil is particularly preferable. The separator that can be used in the present invention is
It has a large ion permeability, has a predetermined mechanical strength, and is an insulating thin film. As the material, olefin polymer, fluorine polymer, cellulose polymer, polyimide, nylon, glass fiber, alumina fiber is used. As the form, a non-woven fabric, a woven fabric, or a microporous film is used. In particular, the material is preferably polypropylene, polyethylene, a mixture of polypropylene and polyethylene, a mixture of polypropylene and Teflon, a mixture of polyethylene and Teflon, and the form is preferably a microporous film. In particular, a microporous film having a pore size of 0.01 to 1 μm and a thickness of 5 to 50 μm is preferable.

After the first heat treatment of the electrode sheet, it is preferable to further perform the second heat treatment in an atmosphere having a dew point of −30 ° C. to −80 ° C. The first heat treatment condition is preferably 100 to 400 ° C, more preferably 150 to 300 ° C, and 200
-300 degreeC is especially preferable. The time is preferably 1 minute or more and 30 hours or less, more preferably 10 minutes or more and 10 hours or less, and particularly preferably 15 minutes or more and 3 hours or less. The dew point of the atmosphere of the second heat treatment condition is more preferably −40 ° C. to −80 ° C. The temperature is preferably 100 to 400 ° C, more preferably 100 to 300 ° C, and particularly preferably 130 to 300 ° C. The time is preferably 1 to 10 hours, more preferably 2 to 6 hours. Although any heating method may be used, hot air blowing and infrared irradiation are preferable.

The electrolytic solution which can be used in the present invention includes propylene carbonate, ethylene carbonate, and
Butylene carbonate, dimethyl carbonate, diethyl carbonate, 1,2-dimethoxyethane, γ-butyrolactone, tetrahydrofuran, 2-methyltetrahydrofuran, dimethylsulfoxide, dioxolane,
1,3-dioxolan, formamide, dimethylformamide, nitromethane, acetonitrile, methyl formate,
Methyl acetate, methyl propionate, phosphoric acid triester,
Trimethoxy methane, dioxolane derivatives, sulfolane, 3-methyl-2-oxazolidinone, propylene carbonate derivatives, tetrahydro derivative, diethyl ether, as a mixture of at least one or more kinds of 1,3-propane sultone, and as the electrolyte, LiClO ₄ , L
iBF ₄ , LiPF ₆ , LiCF ₃ SO ₃ , LiCF _{3
CO 2, LiAsF 6, LiSbF 6} , LiB 10 C
l ₁₀ , lithium lower aliphatic carboxylate, LiAlCl
₄ , a solution in which one or more salts of LiCl, LiBr, LiI, lithium chloroborane, and lithium tetraphenylborate are dissolved. In particular, a mixed solvent of propylene carbonate or ethylene carbonate with 1,2-dimethoxyethane and / or diethyl carbonate
It is preferable to dissolve CF ₃ SO ₃ , LiClO ₄ , LiBF ₄ , and / or LiPF ₆ , and it is particularly preferable to contain at least ethylene carbonate and LiPF ₆ .

The shape of the battery can be applied to any of buttons, coins, sheets, cylinders, corners and the like. For buttons and coins, the mixture is press-formed into pellets, and for sheets, squares and cylinders, the mixture is coated on a current collector, dried, dehydrated, and pressed. A battery is formed by inserting an electrode wound with a pellet, a sheet, or a separator into a battery can, electrically connecting the can and the electrode, injecting an electrolyte, and sealing the battery. At this time, a safety valve can be used as a sealing plate. Furthermore, in order to guarantee the safety of the battery, P
It is preferable to use a TC element.

The bottomed battery outer can that can be used in the present invention is made of nickel-plated steel plate or stainless steel plate (SUS304, SUS304L, SUS304).
N, SUS316, SUS316L, SUS430, S
US444, etc.), nickel-plated stainless steel plate (same as above), aluminum or its alloy, nickel,
They are titanium and copper, and have a shape of a perfect circular cylinder, an elliptical cylinder, a square cylinder, or a rectangular cylinder. In particular, when the outer can also serves as the negative electrode terminal, a stainless steel plate or a nickel-plated iron steel plate is preferable, and when the outer can also serves as the positive electrode terminal, a stainless steel plate, aluminum or an alloy thereof is preferable.

The gasket which can be used in the present invention is made of an olefin polymer, a fluorine polymer, a cellulosic polymer, a polyimide or a polyamide as a material, and the olefin polymer is preferable from the viewpoint of organic solvent resistance and low water permeability, and particularly, Polymers based on propylene are preferred. Further, it is preferably a block copolymer of propylene and ethylene.

The battery of the present invention is optionally covered with an exterior material. Examples of the exterior material include a heat-shrinkable tube, an adhesive tape, a metal film, paper, cloth, paint, a plastic case, and the like. Further, at least a part of the exterior may be provided with a portion that changes color by heat so that the heat history during use can be recognized. A plurality of batteries of the present invention are assembled in series and / or in parallel and stored in a battery pack as needed. In addition to safety elements such as positive temperature coefficient resistors, thermal fuses, fuses and / or current interrupting elements, battery packs have safety circuits (voltage, temperature, current, etc. of each battery and / or assembled battery as a whole, Then, a circuit having a function of interrupting the current may be provided. In addition to the positive and negative terminals of the whole battery pack, the positive and negative terminals of each battery, the temperature detection terminals of the whole battery pack and each battery, the current detection terminals of the whole battery pack, etc. shall be provided as external terminals on the battery pack. Can also. The battery pack may have a built-in voltage conversion circuit (such as a DC-DC converter). The connection of each battery may be fixed by welding a lead plate, or may be fixed by a socket or the like so that it can be easily detached. Further, the battery pack may be provided with a display function of the remaining battery capacity, the presence / absence of charging, the number of times of use, and the like.

The battery of the present invention is used in various devices.
In particular, video movies, portable VCRs with monitors, movie cameras with monitors, compact cameras,
SLR camera, disposable camera, film with lens, notebook computer, notebook word processor, electronic organizer,
It is preferably used for mobile phones, cordless phones, beards, electric tools, electric mixers, automobiles and the like.

[0042]

The present invention will be described in more detail with reference to specific examples, but the present invention is not limited to the examples unless it exceeds the gist of the invention. As the positive electrode current collector, the following aluminum foils of A-1 to 4 and B-1 and 15 μm were prepared. The strengths of these samples after treatment at 230 ° C. for 30 minutes were as shown in Table 1 below. Table 1 Strength of aluminum foil after treatment at 230 ° C for 30 minutes Aluminum foil No Breaking strength (Kg / mm ² ) Breaking elongation (%) A-1 13 5.6 Invention A-2 15 4.8 Invention A-3 13 2.5 Present Invention A-4 8 4.2 Present Invention B-1 6 8.1 Comparative Example B-2 13 0.5 Comparative Example The heat treatment was carried out by a hot air blowing method, and the breaking strength and breaking elongation were measured in Tokyo. Tensile Tester PC-5
0, a sample having a thickness of 15 μm, a width of 10 mm, and a length of 50 mm was used.

Synthesis of Negative Electrode Material 7.37 g of tin monoxide, 7.5 g of stannous pyrophosphate, γ-
Alumina 2.84 g, boric anhydride 1.27 g, calcium carbonate 0.31 g, cesium carbonate 0.74 g, calcium oxide 0.51 g, titanium dioxide (rutile) 1.46 g
Were dry-mixed, placed in an alumina crucible, heated to 500 ° C. at 15 ° C./min in an argon atmosphere, and calcined at 500 ° C. for 3 hours. Then, in an argon atmosphere at 15 ° C /
The temperature was raised to 1200 ° C. in minutes, the firing was performed at 1200 ° C. for 12 hours, and then the temperature was lowered to room temperature at 10 ° C./min. It was taken out of the firing furnace, roughly crushed, and further crushed by a jet mill to obtain a negative electrode material having an average particle size of 7 μm. (Compound example 1
1)

In the X-ray diffraction method using CuKα rays, 2
The product had a broad scattering band having an apex at 20 ° to 40 ° in θ value. No crystalline diffraction line was observed at a 2θ value of 40 ° or more and 70 ° or less.

Example-1 As the negative electrode material, the compound 11 synthesized in Synthesis Example-1 was used, and mixed in a proportion of 86% by weight, flake graphite 6% by weight, and acetylene black 3% by weight, and further mixed. 4% by weight of an aqueous dispersion of polyvinylidene fluoride and 1% by weight of carboxymethyl cellulose were added as a binder and kneaded with water as a medium to prepare a slurry. The slurry to a thickness of 1
Both sides of an 8 μm copper foil were applied by an extrusion method, dried, compression-molded by a calendar press machine, and cut into a predetermined width and length to prepare a strip-shaped negative electrode sheet.
The thickness of the negative electrode sheet was 124 μm. As the positive electrode material, 87% by weight of LiCoO ₂ , 6% by weight of flake graphite,
3% by weight of acetylene black, 3% by weight of an aqueous dispersion of polytetrafluoroethylene as a binder and 1% by weight of sodium polyacrylate were added, and the resulting slurry was kneaded with water as a medium to collect a slurry having a thickness of 15 μm. The same method as described above was applied to both surfaces of the body A-1, dried, pressed and cut.
Then, a strip-shaped positive electrode sheet having a thickness of 210 μm was produced. After spot-welding nickel and aluminum lead plates to the respective ends of the negative electrode sheet and the positive electrode sheet, they were treated with a hot air system at 230 ° C. for 30 minutes to obtain a dew point of −6.
It was dehydrated and dried in dry air of 0 ° C. for 1 hour at 250 ° C. Further, the dehydrated and dried positive electrode sheet (8), the microporous polyethylene film separator, the dehydrated and dried negative electrode sheet (9) and the separator (10) were laminated in this order, and this was spirally wound by a winding machine.

The wound body was housed in a bottomed cylindrical battery can (11) made of iron and plated with nickel, which doubles as a negative electrode terminal. LiPF ₆ and LiBF ₄ were each added to 1 L.
An electrolyte containing 9,0.1 mol and a solvent composed of a mixed solution of ethylene carbonate, dimethyl carbonate, diethyl carbonate, and ethyl propionate in a volume ratio of 2: 4: 3: 1 was injected into the battery can. The battery lid (12) having the positive electrode terminal was caulked via a gasket (13) to produce a cylindrical battery. The positive electrode terminal (12) was connected to the positive electrode sheet (8), and the battery can (11) was connected to the negative electrode sheet (9) by a lead terminal in advance. FIG. 1 shows a cross section of a cylindrical battery. Incidentally, (14) is a safety valve. A cylindrical battery was manufactured in the same manner except that the positive electrode current collector A-1 was changed to the compound shown in Table 2. Charge / discharge conditions are 4.2
˜2.7 V, 1.4 mA / cm ² . The result is
Shown below.

The charge / discharge cycle property is shown in Table 2 by the number of cycles at which the discharge capacity is 85% of the first discharge capacity.
In addition, 100 batteries were prepared, and the open circuit voltage was measured after the battery was stored in a charged state at 25 ° C. for 1 month. The average value and standard deviation thereof are shown in Table 2. Table 2 No. Current collector Cycle property Average open circuit Open circuit voltage Standard deviation of voltage 1 A-1 430 times 4.16V 0.02 Present invention 2 A-2 440 4.16 0.02 〃 3 A-3 445 4.16 0.02 〃 4 A-4 415 4.14 0.04 〃 A B-1 350 4.02 0.13 Comparative example B B-2 320 4.03 0.16 〃

Sample N using the positive electrode current collector of the present invention
o. Compared with A and B of Comparative Examples, Nos. 1 to 4 were preferable because they had excellent charge / discharge cycle characteristics, high open circuit voltage, small standard deviation, and high production yield.

[0049]

EFFECTS OF THE INVENTION By using a metal or alloy foil mainly composed of aluminum showing a specific value of breaking strength and breaking elongation after high-temperature heat treatment for a current collector of a positive electrode as in the present invention, excellent charging and discharging can be achieved. A non-aqueous secondary battery having cycle characteristics and high productivity can be obtained.

[Brief description of drawings]

FIG. 1 is a sectional view of a cylindrical battery used in Examples.

[Explanation of symbols]

 8 Positive electrode sheet 9 Negative electrode sheet 10 Separator 11 Battery can 12 Battery lid 13 Gasket 14 Safety valve

Claims (7)

[Claims] 1. In a non-aqueous secondary battery comprising a positive electrode and a negative electrode containing a material capable of reversibly inserting and extracting lithium, a non-aqueous electrolyte containing a lithium salt, and a separator, the current collector of the positive electrode sheet is mainly aluminum. 40 kg / m at a tensile strength of 7 kg / mm ² or more after being heat-treated at a temperature of 230 ° C. for 30 minutes.
A non-aqueous secondary battery characterized in that it has a m ² or less and a breaking elongation of 1% or more and 15% or less. 2. The tensile strength of the current collector is 8 kg / mm.
^2. The non-aqueous secondary battery according to claim 1, which has a breaking elongation of 2% or more and 15% or less and a breaking elongation of 2% or more and 30 kg / mm ² or less. 3. The non-aqueous secondary battery according to claim 1, wherein the negative electrode material is an amorphous oxide and / or chalcogenide mainly containing Sn. 4. The negative electrode material is represented by the general formula (1) SnM ¹ _a O _t general formula (1) (wherein M ¹ is Al, B, P, Si, Ge, a group 1 element of the periodic table, Represents two or more kinds of elements selected from Group 2 elements, Group 3 elements, and halogen elements, a represents a number of 0.2 or more and 2 or less, and t represents a number of 1 or more and 6 or less) The non-aqueous secondary battery according to claim 1, wherein the non-aqueous secondary battery is a non-aqueous secondary battery. 5. The negative electrode material is represented by general formula (2) Sn _x T _1-x M ¹ _a O _t general formula (2) (wherein T represents a transition metal metal, and V, Ti, Fe, M
n, Co, Ni, Zn, W, and Mo. x represents a number of 0.1 or more and 0.9 or less. The non-aqueous secondary battery according to any one of claims 1 to 3, wherein M ¹ , a, and t are represented by the general formula (1). 6. The negative electrode material is represented by the general formula (3) SnM ² _b O _t general formula (3) (wherein M ² is Al, B, P, Ge, an element of Group 1 and Group 2 of the periodic table). Represents two or more elements selected from an element, a Group 3 element, and a halogen element, b represents a number of 0.2 or more and 2 or less, and t represents a number of 1 or more and 6 or less). The non-aqueous secondary battery according to claim 4. 7. The negative electrode material has the general formula (4) SnM ³ _c M ⁴ _d O _t general formula (4) (wherein, M ³ is at least one of Al, B, P and Ge, and M ⁴ is Represents at least one of Group 1 element, Group 2 element, Group 3 element, and halogen element of the periodic table, and c is 0.2.
Is a number of 2 or more and 2 or less, d is a number of 0.01 or more and 1 or less,
0.2 <c + d <2, t represents a number of 1 or more and 6 or less), The non-aqueous secondary battery according to claim 6.