JPH08250100A - Nonaqueous secondary battery - Google Patents

Abstract

PURPOSE: To provide a separator formed into a thin film to provide high permeability of an electrolyte, by forming the separator for a lithium secondary battery of a cloth in specific thickness or less. CONSTITUTION: In a battery comprising a positive electrode active material 4, negative electrode material 2, separator 3 and an electrolyte containing lithium salt, as the separator 3, a cloth 100μm thick or less is used. In a thread serving as a material of the cloth, direct or doubling the thread from fine sized fiber to normal sized fiber of superfine fiber or the like is used. The cloth is preferable a fabric of 0.01 to 10μm thread size. The fabric contains preferably 20wt.% or more polyethylene as a spinning polymer. In this way, the battery, facilitating manufacture to give a high discharge capacity and an excellent charge/discharge cycle characteristic, is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention has a high capacity and cycleability.
The present invention relates to a novel non-aqueous secondary battery which has excellent safety and storage stability and is easy to manufacture.

[0002]

2. Description of the Related Art In recent years, with the widespread use of portable personal computers and mobile phones, there has been an increasing demand for higher capacity secondary batteries. Therefore, a lithium secondary battery capable of high capacity has been extensively developed. However, in a high-capacity secondary battery, a safety problem due to an abnormality such as a short circuit is a major issue. For example, in a high capacity secondary battery,
When a short circuit occurs inside or outside the battery, the temperature of the battery rapidly rises, which causes an accident that the battery contents are ejected. Various measures have been taken to prevent these accidents, and a typical example is a device related to a separator.

In Japanese Patent Laid-Open No. 60-23,954, etc.,
It has been proposed to use a polymer film having fine pores as a separator. In these methods, the battery heats up due to an external short-circuit, etc., and when it reaches a certain temperature, the micropores are blocked, so that the ion permeability is lost and the heat generation is stopped. It showed a certain degree of effectiveness in prevention. However, even this method is not sufficient for short-circuiting or the like under more severe conditions. Further, in a cylindrical battery, a winding group in which positive and negative electrodes and a separator are laminated is inserted into a cylindrical battery can, and an electrolytic solution is injected. In order to increase the capacity, it is necessary to increase the number of electrodes to be wound up, so that the winding group is tightly bound, and the permeation of the electrolytic solution and the non-uniform distribution of the electrolytic solution components are likely to occur. The above-mentioned polymer film separator having fine pores is disadvantageous to them.

In order to improve these, JP-A-63-30
In JP-A-8-866, it is proposed to use two kinds of microporous films of polyethylene and polypropylene in a stacked manner. Further, JP-A-60-52, JP-A-5-74, 442 and the like propose to use a non-woven fabric as a separator. However, in any of these methods, the separator becomes thick, and the volume of the separator occupying in the battery can having a constant capacity becomes large, which is disadvantageous in increasing the capacity.

[0005]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to develop a thin film separator having a high electrolyte permeability and to obtain a non-aqueous secondary battery having a high capacity and easy to manufacture.

[0006]

The above problems relate to a non-aqueous secondary battery comprising a positive electrode active material, a negative electrode material, a separator and an electrolyte containing a lithium salt, wherein the separator is a cloth having a thickness of 50 μm or less. It could be achieved by the characteristic non-aqueous electrolyte secondary battery.

In the present invention, the cloth refers to a sheet-like fiber product referred to in JIS fiber term (JISL02061284), that is, a woven fabric, a knitted fabric, a non-woven fabric and the like. These structures may be a structure formed by interlacing threads, a structure formed by parallel or laminating without interlacing, a structure formed by laminating and entangling or adhering each other, or a composite structure of these. . Methods of making these fabrics are known,
The manufacturing method is not limited. In the present invention,
Cloth should be 200μm or less, preferably 3μm or more and 100μ
A fabric having a thickness of m or less, more preferably 5 μm or more and 60 μm or less, particularly preferably 10 μm.
The cloth has a thickness of 40 μm or less. Of the fabrics, woven fabrics are particularly preferred. The woven fabric structure (combination of warp and weft) includes plain weave, twill weave, satin weave, and the like, but woven fabrics using any of these and other weaves may be used. 10
In order to make a cloth having a size of 0 μm or less, preferably 60 μm or less, it is preferable to use ultrafine fibers. In recent years, ultra-fine fibers of about 0.01 μm have been developed by the composite spinning method as seen in leather-like materials for clothing,
It is preferable to use these. Methods for producing these ultrafine fibers are known and described in, for example, the Handbook for Industrial Fiber Materials (edited by The Textile Society of Japan, published by Nikkan Kogyo Shimbun, 1994). As the yarn used as the raw material of the cloth of the present invention, fibers having a small diameter such as the above ultrafine fibers to fibers having a normal diameter (for example, it is preferable to use fibers of 0.01 μm to 10 μm) are directly used, or It is possible to use a mixture of several yarns. The diameter of the yarn is preferably 0.01 μm to 10
μm, more preferably 0.02 μm to 7 μm, and particularly preferably 0.02 μm to 5 μm. These yarns may be twisted yarns.

As the spinning polymer, a polymer having a melting point or a softening temperature of 100 ° C. to 200 ° C. is used in order to have a function of closing the voids and decreasing the ion permeability when the battery temperature rises. preferable. These polymers include polyethylene, polypropylene,
Examples thereof include polyvinylidene chloride, polyacrylonitrile, and vinylon. Among these, polyethylene, polypropylene or a copolymer mainly composed of these is preferable, and a copolymer of ethylene and the above polymer component is more preferable. Among the copolymers, ethylene-propylene copolymer and ethylene-vinyl alcohol copolymer are preferable, and the ethylene content is preferably 10% by weight or more, more preferably 20% by weight or more and 90% by weight or less. The cloth of the present invention is preferably a cloth containing 10% by weight or more of ethylene, and further 20% by weight or more and 90% by weight of ethylene.
A cloth including the following is preferable. There are the following methods for changing the amount of ethylene component. A method in which a copolymer polymer is used as a raw material polymer for a yarn, a method in which separately spun yarns are combined to have a predetermined compounding ratio, and a yarn is mixed, and a polyethylene yarn and another polymer yarn are compounded when forming a cloth. There are methods and the like, and any method is preferably used.

The cloth of the present invention is preferably a woven cloth in terms of uniformity. Various known methods can be used as the spinning and woven methods, and the methods are not limited to these methods. It is preferable that these cloths are heat-cut or have their ends woven back to have a predetermined size in order to prevent the end cloth from fraying.

The cloth separator of the present invention may be used in combination with a film-like polymer separator or a separator made of an inorganic material. These separates
An insulating microporous thin film having a large ion permeability and a predetermined mechanical strength is used as the target. Further, it is preferable to have a function of closing the holes at 80 ° C. or higher to increase resistance. A sheet or non-woven fabric made of olefin polymer such as polypropylene and / or polyethylene or glass fiber is used because of its resistance to organic solvent and hydrophobicity. The pore size of the separator is within the range generally used as a battery separator.
For example, 0.01 to 10 μm is used. The thickness of the separator is generally within the range of battery separators. For example, 5 to 300 μm is used. The micropores may be formed by a dry method, a drawing method, a solution or solvent removing method, or a combination thereof. The positive and negative electrodes used in the non-aqueous secondary battery of the present invention can be made by coating a positive electrode mixture or a negative electrode mixture on a current collector. The positive electrode or the negative electrode mixture can contain a positive electrode active material or a negative electrode material, as well as a conductive agent, a binder, a dispersant, a filler, an ion conductive agent, a pressure enhancer or various additives, respectively. The positive electrode active material used in the present invention may be a compound capable of inserting and extracting light metal ions, and in particular,
It is selected from transition metal oxides and transition metal chalcogenides. A transition metal oxide is particularly preferable, and a transition metal oxide containing lithium is particularly preferable.

Preferred transition metals used in the present invention include Ti, V, Cr, Mn, Fe, Co, Ni, Cu,
Nb, Mo and W can be mentioned. Among these transition metal compounds, manganese dioxide, vanadium pentoxide,
Iron oxide, molybdenum oxide, molybdenum sulfide, cobalt oxide, iron sulfide, titanium sulfide and the like are preferable. These compounds can be used alone or in combination of two or more kinds. It can also be used as a transition metal oxide containing lithium.

In addition to lithium compounds and transition metal compounds,
In general, compounds that enhance ionic conductivity, such as Ca ²⁺ ,
Alternatively, an amorphous network forming agent containing P, B or Si (for example, P ₂ O ₅ , Li ₃ PO ₄ , H ₃ BO ₃ , B ₂
O _3, etc. SiO ₂₎ and may be fired by mixing. In addition, alkali metal ions such as Na, K and Mg and /
Or Si, Sn, Al, Ga, Ge, Ce, In, B
You may mix with a compound containing i etc., and may bake. The transition metal oxide containing lithium is, for example, a lithium compound,
It can be synthesized by firing a mixture of transition metal compounds.

Specific examples of the preferable positive electrode active material used in the present invention include JP-A-61-2562, US Pat. Nos. 4,302,518, and JP-A-63-29905.
6, JP-A-1-294364, JP-B-4-3014
6, U.S. Pat. Nos. 5,240,794 and 5,15.
3,081, JP-A-4-328,258, JP-A-5
No. 54,889. Representative compounds are shown below, but the present invention is not limited thereto.

Li _x CoO ₂ , Li _x NiO ₂ , Li _x
Co _a Ni _1-a O ₂ , Li _x Co _b V _1-b O _z , Li _x
Co _b Fe _1-b O _z , Li _x Mn ₂ O ₄ , Li _x Mn
O ₂ , Li _x Mn ₂ O ₃ , Li _x Mn _b Co _2-b O _z ,
_{Li x Mn b Ni 2-b} O z, Li x Mn b V 2-b O z,
Li _x Mn _b Fe _1-b O _z , Li _x Co _c B _1-c O
₂ (where x = 0.05 to 1.2, a = 0.1 to 0.
9, b = 0.8 to 0.98, c = 0.85 to 0.99,
z = 1.5 to 5).

The positive electrode active material used in the present invention can be synthesized by a method of mixing and firing a lithium compound and a transition metal compound or a solution reaction, but a firing method is particularly preferable. Details for firing are described in paragraphs [0035] of JP-A-6-60,867, JP-A-7-14,579 and the like, and these methods can be used. The positive electrode active material obtained by firing may be used after being washed with water, an acidic aqueous solution, an alkaline aqueous solution, or an organic solvent. Further, the method of chemically inserting lithium ions into the transition metal oxide may be a method of synthesizing lithium metal, a lithium alloy, or butyl lithium by reacting with the transition metal oxide.

The average particle size of the positive electrode active material used in the present invention is preferably 0.1 to 40 μm. Especially 0.5 to 15
The volume of the μm particles is preferably 95% or more.
The specific surface area is not particularly limited, but it is 0.
01-50 m < ² > / g is preferable. The pH of the supernatant when 5 g of the positive electrode active material is dissolved in 100 ml of distilled water is preferably 7 or more and 12 or less.

The negative electrode material used in the present invention may be any compound that can absorb and release light metal ions. Among these, light metals, light metal alloys, carbonaceous compounds, inorganic oxides, inorganic chalcogenides, metal complexes, organic polymer compounds and the like are preferable. These may be used alone or in combination. Examples include a combination of a light metal and a carbonaceous compound, a light metal and an inorganic oxide, a combination of a light metal, a carbonaceous compound and an inorganic oxide. These negative electrode materials are preferable because they provide the effects of high capacity, high discharge potential, high safety and high cycleability.

Lithium is preferred as the light metal. Examples of the light metal alloy include a metal forming an alloy with lithium or an alloy containing lithium. Al, Al-Mn, A
l-Mg, Al-Sn, Al-In, and Al-Cd are particularly preferable. The carbonaceous compound is selected from natural graphite, artificial graphite, vapor-grown carbon, calcined carbon of an organic material, and the like, and preferably includes a graphite structure. Further, the carbonaceous compounds, in addition to carbon, a heterologous compound, e.g. B, P, N, S, SiC, B 4 C and may comprise 0 to 10 wt%.

In the present invention, it is preferable to use a combination of an inorganic oxide or inorganic chalcogenide as a negative electrode material and a cloth separator. As an element forming an inorganic oxide or an inorganic chalcogenide, a transition metal or a metal or metalloid element of Groups 15 to 15 of the periodic table is preferable. As the transition metal compound, particularly V, Ti, Fe, M
A single or complex oxide of n, Co, Ni, Zn, W and Mo, or chalcogenide is preferable. More preferable compounds include Li described in JP-A-6-44,972.
_p Co _q V _1-q O _r (where p = 0.1 to 2.5, q =
0-1 and z = 1.3-4.5) can be mentioned.

Compounds of metals and semimetals other than transition metals include elements of Groups 13 to 15 of the periodic table, Al, Ga,
An oxide or chalcogenide composed of Si, Sn, Ge, Pb, Sb, Bi alone or in combination of two or more thereof is selected. For example, Al ₂ O ₃ , Ga ₂ O ₃ ,
SiO, SiO ₂ , GeO, GeO ₂ , SnO, SnO
₂ , SnSiO ₃ , PbO, PbO ₂ , Pb ₂ O ₃ , P
b ₂ O ₄ , Pb ₃ O ₄ , Sb ₂ O ₃ , Sb ₂ O ₄ , Sb
₂ O ₅ , Bi ₂ O ₃ , Bi ₂ O ₄ , Bi ₂ O ₅ , SnS
iO ₃ , GeS, GeS ₂ , SnS, SnS ₂ , Pb
S, PbS ₂ , Sb ₂ S ₃ , Sb ₂ S ₅ , SnSiS ₃
Are preferred. Further, these may be composite oxides with lithium oxide, such as Li ₂ GeO ₃ and Li ₂ SnO ₂ .

The above-mentioned complex chalcogen compound and complex oxide are preferably mainly amorphous when incorporated in a battery. The term "amorphous" as used herein means a substance having a broad scattering band having an apex at a 20 value of 20 ° to 40 ° by an X-ray diffraction method using CuKα rays, and has a crystalline diffraction line. Good. Preferably, the strongest intensity of the crystalline diffraction lines observed at a 2θ value of 40 ° or more and 70 ° or less 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 complex chalcogen compound and complex oxide are preferably represented by the following general formulas (1) to (3). M ¹ M ² pM ³ qZr General formula (1) SnSip M ⁴ qZr General formula (2) SnSipAlsM ⁵ tOr General formula (3) In the formula, M ¹ , M ² and M ³ are different from each other, B, Al and M ³ respectively.
Ga, In, Tl, Si, Ge, Sn, Pb, P, A
s, Sb, Bi, preferably B, Al, Ga, I
n, Tl, Si, Ge, Sn, Pb, P, Sb, Bi, particularly preferably B, Al, Si, Ge, Sn, P
Is. More preferably, they are B, Al, Si, Sn, and P. M ⁴ is the above element other than Sn and Si, and M ⁵ is
It is the above element other than Sn, Si and Al. Z is O,
It is at least one selected from S, Se and Te, preferably O and S, and particularly preferably O. p, q
Are each 0.01 to 10, preferably 0.05 to 5
And particularly preferably 0.1 to 2. s and t are numbers other than 0, and s + t = q. r is 1.
It is 00 to 26, preferably 1.1 to 12, and particularly preferably 1.2 to 6. The valences of M ¹ , M ² and M ³ are not particularly limited, and even if they are single valences,
It may be a mixture of each valence. In addition, M ¹ , M ² , M ³
The ratio of M ² and M ³ is 0.001 to 10 with respect to M ¹ .
It can be continuously changed in the range of molar equivalents, and accordingly, the amount of Z (the value of r in the general formula (1)) is also continuously changed.

Oxides represented by the general formulas (1) to (3)
Examples of complex oxides mainly composed of
However, the present invention is not limited to these. SnB_0.5P
_0.5O₃, SnAl_0.3B_0.5P_0.2O_2.7, SnAl
_0.3B_0.7O_2.5, SnSi_0.8P_0.2O_3.1, SnS
i_0.8B_0.2O_2.9, SnSi_0.8Al_0.2O_2.9, S
nSi_0.6Al_0.2B_0.2O_2.8, SnSi_0.6Al
_0.2P _0.2O₃, SnSi_0.6B_0.2P_0.2O₃, Sn
Si_0.4Al_0.2B_0.4O_2.7, SnSi_0.6Al_0.1
B_0.1P_0.3O_3.25, SnSi_0.6Al_0.1B_0.3P_0.
1O_3.05, SnSi_0.5Al_0.3B_0.4P_0.2O_3.55,
SnSi_0.5Al_0.3B _0.4P_0.5O_4.30, SnSi
_0.8Al_0.3B_0.2P_0.2O_3.85

Various compounds can be included in the negative electrode material of the present invention. For example, Group 1 elements (Li, Na, K, R
b, Cs), Group 2 element (Be, Mg, Ca, Sr, B
a), transition metals (Sc, Ti, V, Cr, Mn, Fe,
Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, T
c, Ru, Rh, Pd, Ag, Cd, lanthanoid metal, Hf, Ta, W, Re, Os, Ir, Pt, Au,
Hg) or a periodic table group 17 element (F, Cl, Br, I) can be included. It may also contain a dopant of various compounds (for example, compounds of Sb, In, and Nb) that enhance electron conductivity. The amount of compound added is 0 to 20 mol%
Is preferred.

As the method for synthesizing the complex chalcogen compound and the complex oxide represented by the general formulas (1) to (3) in the present invention, either a firing method or a solution method can be adopted. For example, the firing method will be described in detail. M ¹ compound, M ²
Compound and M ³ compound (M ¹ , M ² and M ³ are different from each other, Si, Ge, Sn, Pb, P, B, Al, As, S
A predetermined amount of b) may be mixed and baked under the baking conditions described below. The compounds of the present invention also include non-stoichiometric compounds produced during firing and elements having different valences produced by the disproportionation reaction.

The firing conditions are preferably a temperature rising rate of 4 ° C. or more and 2000 ° C. or less per minute,
More preferably, it is 6 ° C. or higher and 2000 ° C. or lower. Particularly preferably, it is 10 ° C or higher and 2000 ° C or lower, and the firing temperature is preferably 250 ° C or higher and 1500 ° C or lower, and more preferably 350 ° C or higher and 1500 ° C.
Or less, particularly preferably 500 ° C or higher and 1500 ° C
And the firing time is 0.01 hours or more 1
It is preferably 00 hours or less, more preferably 0.5 hours or more and 70 hours or less, particularly preferably 1 hour or more and 20 hours or less, and the temperature decreasing rate is 2 ° C or more and 10 ⁷ ° C or less per minute. It is preferably 4 ° C or more and 10 ⁷ ° C or less, particularly preferably 6 ° C or more and 10 ⁷ ° C or less, and particularly preferably 1
It is 0 ° C. or higher and 10 ⁷ ° C. or lower. The rate of temperature rise in the present invention is the average rate of temperature increase from "50% of the firing temperature (indicated in ° C)" to "80% of the firing temperature (indicated in ° C)", and the rate of temperature decrease in the present invention is "Baking temperature (℃
80% of "displayed" to "50% of firing temperature (displayed in ° C)"
Is the average rate of temperature drop until reaching. The temperature may be lowered in the firing furnace or may be taken out of the firing furnace and put in water for cooling. Also, ceramic processing (Gihodo Shuppan 1987), page 217, gun method, Hammer-Anvil method, slap method,
Gas atomization method, plasma spray method, centrifugal quenching method,
An ultraquenching method such as the melt drag method can also be used. See also New Glass Handbook (Maruzen 199
1) Cooling may be performed using the single roller method or the twin roller method described on page 172. In the case of a material that melts during firing, the fired product may be continuously taken out while supplying the raw material during firing. In the case of a material that melts during firing, it is preferable to stir the melt.

The firing gas atmosphere is preferably an atmosphere having an oxygen content of 5% by volume or less, and more preferably an inert gas atmosphere. Examples of the inert gas include nitrogen, argon, helium, krypton, xenon and the like. The average particle size of the compounds represented by the general formulas (1) to (3) used in the present invention is preferably 0.1 to 50 μm,
1.0 to 30 μm is more preferable, and 2.0 to 20 μm is particularly preferable. A well-known crusher or classifier is used to obtain a predetermined particle size. For example, mortar, ball mill, sand mill, vibrating ball mill, satellite ball mill,
A planetary ball mill, a swirling airflow type jet mill, a sieve, etc. are used. At the time of pulverization, wet pulverization in which water or an organic solvent such as methanol is allowed to coexist can be performed as necessary. In order to obtain the desired particle size, it is preferable to carry out classification. The classification method is not particularly limited, and a sieve, an air classifier, or the like can be used as necessary. Classification can be carried out both dry and wet.

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 as a simple method from a weight difference between powders before and after firing. The amount of the light metal inserted into the negative electrode material of the present invention may be close to the deposition potential of the light metal, for example,
50 to 700 mol% is preferable, and 100 to 600 mol% is particularly preferable, based on the negative electrode material. It is preferable that the amount released is larger than the amount inserted. The light metal insertion method is
Electrochemical, chemical and thermal methods are preferred. The electrochemical method is preferably a method in which a light metal contained in the positive electrode active material is electrochemically inserted or a method in which a light metal or an alloy thereof is directly electrochemically inserted. As a chemical method, there is a method of mixing with a light metal, contacting with it, or reacting with an organic metal such as butyllithium. The electrochemical method and the chemical method are preferable. The light metal is particularly preferably lithium or lithium ion.

The surface of the oxide positive electrode active material or negative electrode material used in the present invention can be coated with an oxide having a chemical formula different from that of the positive electrode active material or negative electrode material used. This surface oxide is preferably an oxide containing a compound that is soluble in both acidity and alkalinity. Further, a metal oxide having high electron conductivity is preferable. For example, PbO ₂ , Fe
₂ O ₃ , SnO ₂ , In ₂ O ₃ , ZnO and the like or oxides thereof preferably contain a dopant (for example, a metal having a different valence in the oxide, a halogen element, etc.). Particularly preferably, SiO ₂ , SnO ₂ , Fe ₂
O _3, ZnO, is a PbO _2.

The amount of the surface-treated metal oxide is preferably 0.1 to 10% by weight based on the positive electrode active material or the negative electrode material. Further, 0.2 to 5% by weight is particularly preferable,
Most preferred is 0.3-3% by weight. In addition to this,
The surface of the positive electrode active material or the negative electrode material can be modified.
For example, the surface of the metal oxide is treated with an esterifying agent,
Examples thereof include treatment with a chelating agent, treatment with a conductive polymer, polyethylene oxide and the like. Also, the surface of the negative electrode material can be modified. For example, the treatment may be performed by providing an ion conductive polymer or polyacetylene layer. Further, the positive electrode active material and the negative electrode material may be subjected to a purification step such as washing with water.

As the electrode mixture, a conductive agent, a binder, a filler, a dispersant, an ion conductive agent, a pressure enhancer and various other additives can be used. The conductive agent may be any electron-conductive material that does not cause a chemical change in the constructed battery. Usually, natural graphite (scaly graphite, flake graphite, earthy graphite, etc.), graphite such as artificial graphite, acetylene black, Ketjen black, channel black, furnace black, lamp black,
Carbon blacks such as thermal black, conductive fibers such as carbon fibers and metal fibers, metal powders such as copper, nickel, aluminum and silver, conductive whiskers such as zinc oxide and potassium titanate, oxidation A conductive metal oxide such as titanium or an organic conductive material such as a polyphenylene derivative can be contained alone or as a mixture thereof. Among these conductive agents, acetylene black, and the combined use of graphite and acetylene black are particularly preferable. The amount added is not particularly limited, but is 1
-50% by weight is preferable, and 1-30% by weight is particularly preferable. For carbon and graphite, 2 to 15% by weight is particularly preferable.

As the binder, one kind of a polysaccharide, a thermoplastic resin and a polymer having rubber elasticity or a mixture thereof can be used. Preferred examples are starch, polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, regenerated cellulose,
Diacetyl cellulose, polyvinyl chloride, polyvinylpyrrolidone, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene butadiene rubber, polybutadiene, fluororubber and polyethylene oxide. Can be mentioned. When a compound containing a functional group that reacts with lithium, such as a polysaccharide, is used, it is preferable to add a compound such as an isocyanate group to deactivate the functional group. The amount of the binder added is not particularly limited, but is preferably 1 to 50% by weight, and particularly 2
-30% by weight is preferred. The distribution of the binder in the mixture may be uniform or non-uniform.

As the filler, any fibrous material can be used as long as it does not cause a chemical change in the constructed battery. Generally, olefin polymers such as polypropylene and polyethylene, fibers such as glass and carbon are used. The amount of the filler added is not particularly limited, but is 0
-30% by weight is preferred. As the ionic conductive agent, those known as inorganic and organic solid electrolytes can be used, and details are described in the section of the electrolytic solution. The pressure enhancer is a compound that increases the internal pressure described later, and a typical example is carbonate.

The electrolyte is generally composed of a solvent and a lithium salt (anion and lithium cation) which is soluble in the solvent. As the solvent, propylene carbonate, ethylene carbonate, butylene carbonate,
Dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, γ-butyrolactone, methyl formate, methyl acetate, 1,2-dimethoxyethane, tetrahydrofuran, 2-methyltetrahydrofuran, dimethyl sulfoxide, 1,3-dioxolane, formamide,
Dimethylformamide, dioxolane, acetonitrile, nitromethane, ethyl monoglyme, phosphate triester, trimethoxymethane, dioxolane derivative, sulfolane, 3-methyl-2-oxazolidinone, propylene carbonate derivative, tetrahydrofuran derivative,
Examples thereof include aprotic organic solvents such as ethyl ether and 1,3-propane sultone, and one or more of these may be mixed and used.

Click on the lithium salt soluble in these solvents
For turning on, for example, ClO_Four ^-, BF_Four ^-, PF₆
^-, CF₃SO₃ ^-, CF₃CO₂ ^-, AsF₆ ^-, S
bF₆ ^-, (CF₃SO₂)₂N^-, B_TenCl_Ten ^2-,
(1,2-dimethoxyethane)₂ ClO_Four ^-, Lower fat
Group carboxylate ion, AlCl_Four ^-, Cl^-, Br^-,
I^-Anions of chloroborane compounds, tetraphenylborane
Acid ions can be mentioned, one or two of these
The above can be used. Above all, ring carbon
And / or acyclic carbonates are preferred.
Good. For example, diethyl carbonate, dimethyl car
May contain bonates and methyl ethyl carbonate
preferable. In addition, ethylene carbonate, propylene carbonate
It is preferable to include a carbonate. Also ethylene
In addition to carbonates, propylene carbonate, 1,2
-Dimethoxyethane, dimethyl carbonate or dimethoxy
LiCF is added to an electrolyte solution in which ethyl carbonate is appropriately mixed.₃
SO₃, LiClO_Four, LiBF_FourAnd / or L
iPF₆An electrolyte containing is preferred. With their supporting salts
Is LiPF₆It is particularly preferable to include

The amount of these electrolytes to be added to the battery is not particularly limited, but can be used in the required amount depending on the amount of the positive electrode active material or the negative electrode material and the size of the battery. The concentration of the supporting electrolyte is not particularly limited, but is preferably 0.2 to 3 mol per liter of the electrolytic solution. In addition to the electrolytic solution, the following solid electrolytes can be used together. Solid electrolytes are classified into inorganic solid electrolytes and organic solid electrolytes. Li-nitrides, halides, oxyacid salts, and the like are well known as inorganic solid electrolytes. Above all, Li
_{3 N, LiI, Li 5 NI} 2, Li 3 N-LiI-Li
_{OH, Li 4 SiO 4, Li} 4 SiO 4 -LiI-Li
_{OH, x Li 3 PO 4 -} (1-x) Li 4 SiO 4, Li 2 S
iS ₃ , phosphorus sulfide compounds and the like are effective.

In the organic solid electrolyte, a polyethylene oxide derivative or a polymer containing the derivative, a polypropylene oxide derivative or a polymer containing the derivative, a polymer containing an ion dissociating group, a mixture of the polymer containing the ion dissociating group and the above aprotic electrolyte solution. A polymer matrix material containing a phosphoric acid ester polymer and an aprotic polar solvent is effective. Furthermore, there is also a method of adding polyacrylonitrile to the electrolytic solution. Also known is a method of using an inorganic and organic solid electrolyte in combination.

Further, other compounds may be added to the electrolyte for the purpose of improving discharge and charge / discharge characteristics. For example, pyridine, triethylphosphite, triethanolamine, cyclic ether, ethylenediamine, n-glyme, hexaphosphoric acid triamide, nitrobenzene derivative,
Sulfur, quinone imine dye, N-substituted oxazolidinone and N, N'-substituted imidazolidinone, ethylene glycol dialkyl ether, quaternary ammonium salt, polyethylene glycol, pyrrole, 2-methoxyethanol, A
lCl ₃ , a conductive polymer electrode active material monomer, triethylenephosphoramide, trialkylphosphine, morpholine, an aryl compound having a carbonyl group, 12-
Crown ethers such as Crown-4, hexamethylphosphoric triamide and 4-alkylmorpholine,
Examples include bicyclic tertiary amines, oils, quaternary phosphonium salts, and tertiary sulfonium salts.

Further, in order to make the electrolytic solution nonflammable, a halogen-containing solvent such as carbon tetrachloride or ethylene trifluoride chloride can be contained in the electrolytic solution. Further, the electrolytic solution may contain carbon dioxide gas in order to have suitability for high temperature storage. Further, the mixture of the positive electrode and the negative electrode can contain an electrolytic solution or an electrolyte. For example, a method is known in which the ion conductive polymer, nitromethane, and an electrolytic solution are contained.

The collector of the electrode active material may be any electron conductor that does not cause a chemical change in the constructed battery. For example, for the positive electrode, in addition to stainless steel, nickel, aluminum, titanium, carbon, or the like, a material obtained by treating the surface of aluminum or stainless steel with carbon, nickel, titanium, or silver is used. Particularly, aluminum or aluminum alloy is preferable. For the negative electrode, in addition to stainless steel, nickel, copper, titanium, aluminum, carbon, etc. as a material, a material obtained by treating the surface of copper or stainless steel with carbon, nickel, titanium or silver, or an Al-Cd alloy is used. To be Particularly, copper or copper alloy is preferable. It is also used to oxidize the surface of these materials. Further, it is desirable to make the surface of the current collector uneven by surface treatment. As the shape, in addition to the foil, a film, a sheet, a net, a punched product, a lath body, a porous body, a foamed body, a molded body of a fiber group and the like are used. The thickness is not particularly limited, but 1
Those having a thickness of up to 500 μm are used.

The shape of the battery can be any of coins, buttons, sheets, cylinders, flats, corners and the like. When the shape of the battery is a coin or a button, the mixture of the positive electrode active material and the negative electrode material is mainly used after being compressed into a pellet shape.
The thickness and diameter of the pellet are determined by the size of the battery. When the shape of the battery is a sheet, a cylinder, or a corner, the mixture of the positive electrode active material and the negative electrode material is mainly used after being applied (coated), dried, and compressed on the current collector. As a coating method, a general method can be used. For example,
Reverse roll method, direct roll method, blade method,
Knife method, extrusion method, curtain method, gravure method, bar method, dip method and squeeze method can be mentioned. Among them, the blade method, the knife method and the extrusion method are preferable. Application is 0.1-10
It is preferably carried out at a speed of 0 m / min. On this occasion,
By selecting the above coating method according to the solution physical properties and drying properties of the mixture, a good surface state of the coating layer can be obtained. The coating may be performed one by one or simultaneously on both sides. The coating may be continuous, intermittent or striped. The thickness, length and width of the coating layer are determined by the size of the battery, but the thickness of the coating layer on one side is particularly preferably 1 to 2000 μm in the compressed state after drying.

As a method for drying or dehydrating the pellets or sheets, a generally adopted method can be used. In particular, it is preferable to use hot air, vacuum, infrared rays, far infrared rays, electron beams, and low humidity air alone or in combination. The temperature is preferably in the range of 80 to 350 ° C, particularly 10
The range of 0 to 250 ° C. is preferable. The water content of the whole battery is preferably 2000 ppm or less, and the content of each of the positive electrode mixture, the negative electrode mixture and the electrolyte is preferably 500 ppm or less from the viewpoint of cycleability. As a pellet or sheet pressing method, a generally adopted method can be used, but a die pressing method or a calendar pressing method is particularly preferable. The pressing pressure is not particularly limited, but is 0.2 to 3 t /
cm ² is preferred. The press speed of the calendar press method is preferably 0.1 to 50 m / min. The pressing temperature is preferably room temperature to 200 ° C. The width ratio of the negative electrode sheet to the positive electrode sheet is preferably 0.9 to 1.1. In particular,
0.95-1.0 is preferable. Since the content ratio of the positive electrode active material and the negative electrode material differs depending on the compound type and mixture formulation,
Although not limited, it can be set to an optimum value in terms of capacity, cycleability, and safety.

Stacked with the mixture sheet with a separator
After being fitted, the sheets can be rolled or folded.
Insert it into the can, connect the can and the sheet electrically, and
Inject and use the sealing plate to form a battery can. At this time,
The safety valve can be used as a sealing plate. Safety valve
In addition, equipped with various conventionally known safety elements
Is also good. For example, fuses,
Immetal, PTC element, etc. are used. Also, the safety valve
In addition to the above, cut into the battery can as a measure to increase the internal pressure of the battery can
Inserting method, gasket cracking method or sealing plate cracking
Method or cutting method with lead plate can be used.
Wear. In addition, the charger has built-in measures against overcharge and overdischarge.
Either have a protection circuit or connect it independently
Good. Also, as a measure against overcharge, increase the internal pressure of the battery.
It is possible to provide a method of cutting off the electric current. This and
A compound that raises the internal pressure in the mixture or in the electrolyte.
Can be included in. As a compound that increases internal pressure
Is Li₂CO₃, LiHCO ₃, Na₂CO₃, Na
HCO₃, CaCO₃, MgCO₃Such as carbonate
can give. Cans and lead plates are made of metal or
Alloys can be used. For example, iron, nickel, chi
Gold such as tan, chrome, molybdenum, copper, aluminum
A genus or an alloy thereof is used. Caps, cans,
Welding methods for sheets and lead plates are known methods (eg, direct current or
Is AC electric welding, laser welding, ultrasonic welding)
Can be Sealing agents for sealing are asphalt, etc.
It is possible to use conventionally known compounds and mixtures of
it can.

The application of the non-aqueous secondary battery of the present invention is not particularly limited. For example, when it is mounted on an electronic device, a color notebook computer, a black and white notebook computer, a sub notebook computer, a pen input computer, a pocket (palmtop). PC, notebook word processor, pocket word processor, e-book player, mobile phone, cordless phone handset, pager, handy terminal, mobile fax, mobile copy, mobile printer, headphone stereo, video movie, LCD TV, handy cleaner, portable CD, Mini disks, electric shavers, electronic translators, car phones, transceivers, power tools, electronic organizers, calculators, memory cards, tape recorders, radios, backup power supplies, memory cards, etc. Other consumer products include automobiles, electric vehicles, motors, lighting equipment, toys, game machines, road conditioners, irons, watches, strobes, cameras, medical equipment (pacemakers, hearing aids, shoulder massagers, etc.) and the like. Furthermore, it can be used for various military purposes and for space. It can also be combined with other secondary batteries, solar cells, or primary batteries.

[0045]

EXAMPLES The present invention will be described in more detail with reference to specific examples below, but the present invention is not limited to the examples as long as the gist of the invention is not exceeded. Example 1 SnSi _0.8 Al having an average particle size of 6 μm was used as a negative electrode material.
86% by weight of _0.2 B _0.4 P _0.2 O ₄ , 6% by weight of scaly graphite and 3% by weight of acetylene black were mixed, and further 4% by weight of an aqueous dispersion of polyvinylidene fluoride as a binder and 1% of carboxymethylcellulose. Add wt%,
A slurry was prepared by kneading with water as a medium. The slurry was applied on both sides of a copper foil having a thickness of 18 μm by an extrusion method, dried and compression-molded by a calender press, and cut into 55 mm width and 525 mm length to prepare a strip-shaped negative electrode sheet. The thickness of the negative electrode sheet was 124 μm. 87% by weight of LiCoO ₂ as a positive electrode material,
6% by weight of scaly graphite, 3% by weight of acetylene black, 3% by weight of polytetrafluoroethylene aqueous dispersion as a binder and 1% by weight of sodium polyacrylate were added,
The slurry obtained by kneading with water as a medium has a thickness of 20μ.
A strip-shaped positive electrode sheet was prepared by coating and drying on both sides of an aluminum foil of m in the same manner as described above, press-compressing, and then cutting into 53 mm width and 500 mm length. The thickness of the positive electrode sheet was 220 μm. For the separator, the following materials were cut into a width of 59 mm and a length of 620 mm to obtain a separator sheet. After spot welding nickel and aluminum lead plates to the respective ends of the negative electrode sheet and the positive electrode sheet, dehydration drying was performed for 2 hours at 150 ° C. in dry air having a dew point of −40 ° C. or less.

Further, the dehydrated and dried positive electrode sheet, the separator, the dehydrated and dried negative electrode sheet and the separator were laminated in this order so as to be placed in a battery can having an inner diameter of 17.4 mm.
A winding group was created by spirally winding and tapering the outermost periphery. The following was used as the separator. A 35 μm-thick non-woven fabric made by thermal bonding using a separator S-1 and a 3 μm polyethylene compound yarn, which is obtained by heat-cutting a 35 μm-thick cloth woven using 3 μm polyethylene compound yarn so as to have the above dimensions. Separator S-2, microporosity with a film thickness of 35 μm (average pore size 30 μm,
The porosity of 40%) S-3 was used as the polyethylene separator, and the winding groups using the respective separators were used as W-1, W-2, and W-3, respectively. 25 these samples
After immersing in a mixed solvent of ethylene carbonate and dimethyl carbonate (volume ratio 3: 7) for 10 minutes under the condition of ℃, unwind it and obtain the ratio of the solvent wet part and the non-wet part of the separator to obtain the permeability. did. The experiment was performed for each of 5 pieces, and the average was taken. As a result, samples W-1, W
The penetration rates of -2 and W-3 are 100%, 91%,
It was 32%. The cloth of the present invention has a high permeability of the solvent which is a model of the electrolytic solution, while the separator S other than the present invention is used.
The sample W-3 using -3 has significantly poor permeability. Sample W
In -3, it took 2 hours to show a penetration rate of 96%. From this, using a separator outside the present invention,
It takes time for the step after the liquid injection, for example, sealing and precharging, and the productivity is poor.

Example 2 Winding groups W-1 to W-3 prepared in the same manner as in Example 1
Was housed in a bottomed cylindrical battery can (11) made of iron and plated with nickel and also serving as a negative electrode terminal. LiP per 1L
Containing 0.9 and 0.1 mol of F ₆ and LiBF ₄ , respectively,
An electrolyte composed of a 2: 2: 6 volume mixture of ethylene carbonate, butylene carbonate and dimethyl carbonate as a solvent was injected into a battery can. Immediately after the injection, the battery lid (12) having a positive electrode terminal was caulked and sealed with a gasket (13) interposed therebetween to produce cylindrical batteries D-1 to D-3.
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) in advance by a lead terminal. FIG. 2 shows a cross section of the cylindrical battery. Incidentally, (14) is a safety valve. The charging / discharging test was started 1 hour after the sealing. Charge / discharge conditions are 4.3 to 2.7.
V was 1 mA / cm ² . The results are shown below.

Description of abbreviations: a; battery number, b; first discharge capacity (mWh), c; capacity retention ratio (ratio between capacity at 100th cycle and capacity at first cycle is expressed in%) No. a Battery number b Capacity c Capacity retention rate 1 D-1 5880 94% 2 D-2 5640 89 3 D-3 5500 83 From these results, when the cloth separator of the present invention is used, high capacity and capacity retention are obtained. It can be seen that a highly stable battery can be made. Furthermore, it can be seen that the woven fabric is superior to the non-woven fabric.

Example 3 S- except that the separator S-1 of Example 1 was replaced by a yarn spun from an ethylene-propylene copolymer.
Using the same separators S4 to S7 as in Example 1, winding groups W-4 to W-7 were made in exactly the same manner as in Example 1. still,
The weight ratio of ethylene from S-4 to S-6 is 90 each.
%, 60%, 30% and 10%. Using these winding groups, batteries D-4 to D- were made in exactly the same manner as in Example 2.
Created 7. Further, the same test as in Example 2 was performed and the following results were obtained. No. a Battery number b Capacity c Capacity retention 1 D-4 5920 93% 2 D-5 5990 94 3 D-6 5980 94 4 D-7 5760 88 From this result, woven fabric made of a thread containing 10% ethylene. All of them showed good performance except for Battery D-7 which used the separator of.

Example 4 Separators S-1 and S-2 of Example 1 having different thicknesses were used. Separators with thickness differences of 60 μm and 90 μm for S-1 are S-8, S-9, and separators with thickness differences of 60 μm and 90 μm for S-2 are S-, respectively.
10 and S-11, batteries D-8 to D-11 were prepared in exactly the same manner as in Examples 1 and 2. Using these batteries, the first discharge capacity was set to 25 ° C. in the same manner as in Example 2.
It was measured at. Further, the first discharge capacity of the battery stored at 0 ° C was measured, and the ratio (%) to the measured value at 25 ° C
Was calculated. As a result, in the battery using the woven fabric separator, D-1 (78%), D-8 (72%), D-9
(66%), D for batteries using non-woven separator
-2 (63%), D-10 (42%), D-11 (25
%), Indicating that the woven fabric separator is excellent.
When a separator having a thickness of 100 μm or more was used, the winding group could not be inserted into the battery can.

Example 5 SnSi having an average particle size of 6 μm of the negative electrode material of Example 1_0.8A
l_0.2B_0.4P_0.2O_Four Instead of SnSiO₃The same
Negative electrode sheet A in exactly the same manner as in Example 1 except that the amount was used.
-12 was created. Furthermore, SnSi_0.8Al_0.2B_0.4
P_0.2O_FourInstead of commercially available petroleum coke (Japan Petro
Negative electrode sheet A-14 is made using PC-R manufactured by Laem Co.
Was. The same positive electrode sheet as in Example 1 was used.
A-12 and separators S-1 and S-3 combined
Then, batteries D-12 and D-13 were made. Similarly, the negative electrode
A-14 and separators S-1 and S-3 are combined
Accordingly, batteries D-14 and D-15 were made. Battery D-1
4, D-15, the electrode thickness so that the discharge capacity is maximized.
I adjusted. Use these batteries D-12 to D-15
Then, the same experiment as in Example 2 was performed. In Example 2
Has a large capacity and capacity retention rate in batteries D-1 and D-3.
A difference was observed, but a small difference was observed between D-12 and 13, D-14
And 15 showed almost no difference. This thing
The effect of the cloth of the present invention is the combination with the negative electrode material of the present invention.
It was found that a particularly remarkable effect was exhibited. Example 6 Using the negative electrode sheet A-12 of Example 5, the separator is
Polyethylene of S-1 to S-3 of Example 1 was
Except for changing to Ren, the same S-16 to S-18
Battery D-16 was used in the same manner as in Example 5 except for the above.
~ Made D-18. Batteries D-12, D-16 to D-1
8 was used to perform the same experiment as in Example 2, and the following results were obtained.
Was. No. a Battery number b Capacity c Capacity retention 1 D-12 5800 92% 2 D-16 5730 88 3 D-17 5540 84 4 D-18 5370 79 Battery D-16 to 18 compares the effect of the present invention.
Even if the fruit is polypropylene, it is almost the same as in Example 2.
Recognize.

Example 7 SnSi having an average particle size of 6 μm of the negative electrode material of Example 1_0.8A
l_0.2B_0.4P_0.2O _FourInstead of SnSi_0.5B
_0.3P_0.1Mg_0.1O_2.6Example 1 except that the same amount is used
Negative electrode sheet A-19 was prepared in exactly the same manner as in. Negative electrode
Except for using A-19, the same as in Examples 1 and 2.
Then, batteries D-19 to 21 were prepared and the same experiment as in Example 2 was performed.
As a result, almost the same results as in Example 2 were obtained.
Therefore, using Mg, which is a Group 2 element of the periodic table of this experiment,
The cloth separator of the present invention is also effective for negative electrode materials.
It was shown to be.

[0053]

INDUSTRIAL APPLICABILITY As in the present invention, by using a cloth as a separator, a non-aqueous secondary battery which is easy to manufacture and has a high discharge capacity and excellent charge / discharge cycle characteristics can be obtained.

[Brief description of drawings]

FIG. 1 shows a cross-sectional view of a cylindrical battery used in an example.

[Explanation of symbols]

 1 Negative Electrode Sealing Plate 2 Negative Electrode Mixture Pellets 3 Separator 4 Positive Electrode Mixture Pellets 5 Current Collector 6 Positive Electrode Case 7 Gasket 8 Positive Electrode Sheet 9 Negative Electrode Sheet 10 Separator 11 Battery Can 12 Battery Lid 13 Gasket 14 Safety Valve

Claims (6)

[Claims] 1. A non-aqueous secondary battery comprising a positive electrode active material, a negative electrode material, a separator and an electrolyte containing a lithium salt, wherein the separator is a cloth having a thickness of 100 μm or less. battery. 2. The non-aqueous electrolyte secondary battery according to claim 1, wherein the cloth is a woven cloth having a thickness of 100 μm or less. 3. The separator is 0.01 μm or more and 10 or more.
The non-aqueous electrolyte secondary battery according to claim 1 or 2, wherein the non-aqueous electrolyte secondary battery is a woven fabric made of yarn having a diameter of not more than μm. 4. The woven fabric comprises at least 20 polyethylene.
The non-aqueous electrolyte secondary battery according to claim 3, wherein the non-aqueous electrolyte secondary battery contains 50 wt%. 5. The non-aqueous electrolyte secondary battery according to claim 1, wherein an end portion of the cloth is heat-cut or woven. 6. The non-aqueous secondary battery according to claim 1, wherein the negative electrode material is a compound represented by the following general formula (1). M ¹ M ² pM ³ qZr General formula (1) In the formula, M ¹ , M ² and M ³ are different from each other, B, Al and
Ga, In, Tl, Si, Ge, Sn, Pb, P, A
s, Sb and Bi, Z is at least one selected from O, S, Se and Te, and p and q are each 0.01 to 1
0 and r is 1.00 to 26.