JPH10241740A - Nonaqueous system battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make extremely thin an insulated coat for improving battery capacity, and reduce the deterioration of battery performance under high temperature by fixing the insulated coat, composed of an aggregate of insulating material particles, to a surface on a side wherein the active material of the current collecting foil of positive and negative electrodes is not formed covered. SOLUTION: A positive electrode active material dispersion is applied to one side surface of a current-collecting body foil 4a of a positive electrode plate 4 to be dried, and is formed covered of a positive electrode active material layer 4b. Negative electrode active material slurry is applied to one side surface of a current-collecting body layer 5a of a negative electrode plate 5 to be dried, and is formed covered of a negative electrode active material layer 5b. Then, an α-Al2 O3 fine powder and polyvinylidene fluoride powder are mixed, and N-methyl pyrrolidone is added to form dispersion by further mixing thereto. The dispersion is applied uniformly to the surface of the current collecting body foil 4a and 4b on a side (where the active materials of the positive and negative electrodes 4 and 5 are not formed covered), and is dried, and an insulated coat 7, composed of an insulation material particle aggregate, is fixed thereto. Separators 6 are nippedly wound on the positive and negative electrodes 4 and 5, thereto the insulated coat 7 is fixed, to obtain an electrode laminating layer body 1 composed of a unit battery layer 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a separator provided between a positive electrode plate having a current collector foil coated with a positive electrode active material and a negative electrode plate having a current collector foil coated with a negative electrode active material. Further, the present invention relates to a wound or stacked battery which is stacked and stored in a battery can, wherein the electrolyte solvent is a non-aqueous battery. In particular, the present invention relates to an improvement in a collector foil using a positive electrode and a negative electrode in which an active material is adhered to only one surface.

[0002]

2. Description of the Related Art A lithium ion secondary battery using a non-aqueous electrolytic solution is being used as a power source for portable electronic devices because of its high voltage, high capacity, high output, and light weight. In such a lithium ion secondary battery, generally, an aluminum foil is used as a current collector of a positive electrode, and a lithium composite oxide as a positive electrode active material is applied thereto to form a positive electrode plate, and a current collector of a negative electrode is formed. Using copper foil as
A negative electrode plate is formed by applying a material containing carbon, which is a negative electrode active material, to this. An electrode plate laminate in which a unit battery layer is formed by interposing a microporous film made of polyolefin (polyethylene, polypropylene, etc.) as a separator between the positive electrode plate and the negative electrode plate, and the unit battery layer is spirally wound, Housed in a cylindrical metal can.

[0003] Currently available lithium ion secondary batteries include a positive electrode plate and a negative electrode plate each having an active material coated on both surfaces of a current collector foil, and two separators in the order of a separator, a negative electrode, a separator, and a positive electrode. The stacked unit battery layers are wound in a spiral shape, or a positive electrode plate and a negative electrode plate with an active material applied to one side of a current collector foil, and two separators, a separator, a negative electrode, a separator, and a positive electrode in the order of positive electrode. A unit battery layer in which an active material and a negative electrode active material are stacked so as to face each other may be wound.

[0004]

In a non-aqueous battery, the ionic conductivity of a non-aqueous electrolyte is low, so that the area of the electrode is extremely larger than that of a water-based battery in order to obtain sufficient input / output characteristics. For this reason, the area of the separator is inevitably increased, which is a factor that increases the battery manufacturing cost.

Further, in a battery in which a unit battery layer is formed using one positive electrode plate and one negative electrode plate each having an active material applied to only one surface of the current collector foil, the active material is applied only to one surface of the current collector foil. Since the active material is not applied, the positive electrode current collector foil surface and the negative electrode current collector foil surface where the active material is not applied between the unit battery layers are arranged so as to face each other. However, at present, an extra cost is required because a polyolefin microporous membrane is also used for insulation between the two. Also, the polyolefin microporous membrane is an independent membrane,
Since it is necessary to have enough mechanical strength to withstand winding, it is impossible to reduce the thickness beyond a certain level. In order to reduce costs and improve battery capacity, an inexpensive and thin insulating film other than a polyolefin microporous film is required for insulation between metal foils.

[0006] Non-aqueous batteries are used as power sources for mobile communication devices such as mobile phones. However, if they are left in a car exposed to direct sunlight in the summer, battery performance can be improved even at high temperatures. It is necessary that it does not significantly decrease. However, in a nonaqueous battery using an electrolyte containing hydrofluoric acid (hereinafter referred to as HF) which is currently in circulation, at high temperatures, the electrolyte solution reacts with water remaining in the battery can and decomposes to form HF.
However, a large decrease in battery performance could not be avoided. As a method of preventing this deterioration, a method of mixing particles that adsorb HF or the like in the active material layer, a method of dispersing the particles in an electrolytic solution, and the like have been proposed. However, in the former, the electron conductivity in the active material layer is reduced, and the input / output characteristics of the battery are deteriorated.
In the latter case, it is difficult to inject liquid into the battery can, so the amount that can be brought into the battery can decreases,
The effect was small.

The present invention uses an aggregate of insulating material particles as an insulating film between current collector foils, thereby making it possible to make the insulating film inexpensive and extremely thin, to improve battery capacity, It is still another object of the present invention to provide a battery which has a small performance degradation at a high temperature without lowering the battery performance.

[0008]

Means for Solving the Problems In order to achieve the above object, the present inventors have found that an insulating film can be manufactured thin and inexpensively by fixing and integrating the insulating film on a current collector foil. The present invention has been accomplished. That is, the present invention provides a positive electrode plate in which the positive electrode active material is applied only to one surface of the current collector foil, and a negative electrode plate in which the negative electrode active material is applied only to one surface of the current collector foil. The layers are arranged so as to face each other, and in a nonaqueous battery including a separator interposed therebetween, at least one of the collector foils of the positive electrode plate and the negative electrode plate, on the side on which the active material layer is not adhered. The present invention relates to a non-aqueous battery in which an insulating film made of an aggregate of insulating material particles is fixed on a surface. According to the present invention, the insulating film between the positive electrode current collector foil and the negative electrode current collector foil is integrated with the current collector foil, so that the insulating film can be thinned, and The number of components at the time is from a total of four from the positive electrode, the negative electrode, and two separators (one between the active material layers and one between the current collector foils) to the total number of the positive electrode, the negative electrode, and one separator (the active material layer) It is reduced to three sheets and productivity is improved.

As the current collector foil, aluminum,
Metal foil such as copper, titanium, nickel, etc., expanded metal, foamed metal, carbon cloth, carbon paper and the like are used. As the positive electrode active material, Li, Na,
An alkali metal or alkaline earth metal such as Ca;
a composite oxide with a transition metal such as o, Ni, Mn, Fe,
Alternatively, a composite oxide of the alkali metal or alkaline earth metal, transition metal, and non-transition metal can be used. For example, Li _x CoO ₂ having a layered structure and capable of electrochemically storing and releasing lithium in an ion state (0 <x ≦
1.1), Li _x NiO ₂ (0 <x ≦ 1.1), Li _x N
i _y Co _(1-y) O ₂ (0 <x ≦ 1.1, 0 <y <1) and Li _x MnyO ₄ (0 <x ≦ 1.5, 1.66 <y ≦
2) and the like.

As the negative electrode active material, carbonaceous materials such as coke, graphite, and amorphous carbon (having a shape of
Use a substance that can occlude and release lithium electrically in the form of ions, such as crushed, scale-like, spherical, or fibrous shapes) or an amorphous inorganic material (SnO.SiO ₂ ). Can be. The positive electrode plate includes not only one in which the active material is applied to the entirety of one surface of the current collector foil, but also one in which the active material is partially applied, but the other surface has no active material. The active material is not adhered, and the insulating material particle aggregate is fixed. The same applies to the negative electrode plate.
In the negative electrode plate and the positive electrode plate, the width of the negative electrode plate is made larger than the width of the positive electrode plate in order to prevent a displacement at the time of winding and a short circuit due to saturation of the doping amount of lithium ions at the end of the negative electrode. Therefore, the insulating film may be attached to both the positive electrode plate and the negative electrode plate or to one of them. However, it is preferable that the insulating film is attached to at least the negative electrode plate. When an insulating film is applied to both the positive electrode plate and the negative electrode plate, even if the insulating film has a defect such as a pinhole, it is possible to prevent a short circuit between the two electrodes.

As the separator, there is used a porous membrane having no electron conductivity, ion conductivity, high resistance to an organic solvent, and a fine pore diameter, for example, a polyolefin resin (polyethylene, polypropylene, etc.). Examples thereof include a microporous membrane, a woven porous fiber of polyolefin, a nonwoven fabric thereof, and an aggregate of insulating substance particles. In particular, when an aggregate of insulating material particles is used as a separator, the separator is fixed on the electrode, so the number of handling members during winding is a positive electrode, a negative electrode, and a negative electrode when the above-described independent membrane separator is used. The number of separators can be reduced from three to two for a positive electrode and a negative electrode. In addition, in the case of an independent membrane such as a microporous membrane, since it is not necessary to protrude from the electrode in the width direction, which is indispensable in manufacturing, it is necessary to increase the width of the electrode accordingly and increase the electrode active material that can be brought into the battery can. Battery capacity can be increased.

The electrode plate laminate is formed by spirally winding a unit battery layer obtained by laminating a negative electrode plate, a separator, and a positive electrode plate as described above with a winding machine (winding type). It is manufactured by a method of overlapping in parallel via an insulating film (simple stacking type), a method of folding a unit battery layer and an insulating film in a predetermined width and arranging them in parallel (a 99-fold type). You.

The insulative material particle aggregate used as the insulating film includes only the insulative material particles and a binder or the insulative material particles. The insulating material particles include oxides (Li ₂ O, BeO, B ₂ O ₃ , Na ₂ O, MgO, Al
₂ O ₃ , SiO ₂ , P ₂ O ₅ , CaO, Cr ₂ O 3, Fe
₂ O ₃ , ZnO ₂ , ZrO, TiO ₂ , zeolite, nitride (BN, AlN, Si ₃ N ₄ , Ba ₃ N _2, etc.), carbonate (MgCO ₃ , CaCO _3, etc.), sulfate (CaSO 4) , B
aSo4, etc.) and resins (polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyacrylonitrile, polymethyl methacrylate, polyacrylate, fluorine resins (polytetrafluoroethylene, polyvinylidene fluoride, etc.), polyamide resins , Polyimide resin, polyester resin, polycarbonate resin, polyphenylene oxide resin, silicon resin, phenol resin, urea resin, melamine resin, polyurethane resin, polyether resin (polyethylene oxide, polypropylene oxide, etc.), epoxy resin, acetal resin, AS resin, ABS resin, etc.), and preferably particles of an inorganic substance or a heat-resistant resin,
More preferably, inorganic particles are used. By adsorbing by-products and residual moisture in the battery, such particles can be used as an insulating film to increase the amount brought into the battery can without lowering the battery performance than other methods. become able to do. The particle diameter of the insulating material particles is, for example, one having an average particle diameter of 100 μm, preferably 1 μm.
Those having a size of 0 μm or less, more preferably those having a size of 1 μm or less are used. The thickness of the insulating film is not particularly limited, but is preferably 1 μm to 100 μm, and more preferably 10 μm to 50 μm.

As the binder used for the above-mentioned insulating material particle aggregate, fluorine rubber, polyvinylidene fluoride, latex and the like can be mentioned. In consideration of heat resistance and solvent resistance, a fluorine-based binder such as fluorine rubber and fluororesin is used. Is preferred. The amount of the binder is such that the volume of the binder is 5/3 times or less, preferably 1/2 times or less, more preferably 1/5 times or less of the volume of the insulating particles. It is mentioned.

As a method of fixing the insulating substance particles, the insulating substance particles are dispersed in a solution in which a binder is dissolved in a solvent, and the prepared slurry is applied on a current collector foil, and then dried at a high temperature. To remove the solvent. In addition, a spray method, a method in which a mixture of a binder and insulating material particles are arranged on a current collector foil, heated to a temperature equal to or higher than the melting temperature of the binder, and then cooled, and the like are included, but particularly limited ones are included. is not.

The non-aqueous electrolyte used for the non-aqueous battery includes LiBF ₄ , LiPF ₆ , LiClO ₄ , LiA
sF ₆ , CF ₃ SO ₃ Li, (CF ₃ SO ₂ ) 2 N · Li,
LiI, LiAlCl ₄ , NaClO ₄ , NaBF ₄ , N
aI, (n-Bu) 4NClO 4, (n-Bu) 4NB
An electrolyte such as F ₄ or KPF ₆ may be used alone or in combination of two or more and dissolved in an organic solvent to be used as an organic electrolyte. In particular, when an electrolyte containing fluorine is used, the effect of preventing deterioration under high temperature in the present invention is great. The electrolyte concentration in the organic electrolyte is preferably about 0.1 to 2.5M.

Examples of the organic solvent used include ethers, ketones, lactones, nitriles, amines, amides, sulfur compounds, chlorinated hydrocarbons, esters, carbonates, nitro compounds, and phosphate esters. Compounds, sulfolane compounds and the like can be used, and among them, ethers, ketones, nitriles, chlorinated hydrocarbons, carbonates, and sulfolane compounds are particularly preferable. More preferred are cyclic carbonates. Typical examples thereof include tetrahydrofuran, γ-butyrolactone, 1,2-dimethoxyethane, 1,2-diethoxyethane, propylene carbonate, ethylene carbonate, dimethyl sulfoxide, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate and mixtures thereof. Although a solvent etc. can be mentioned, it is not necessarily limited to these.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail by way of examples.

[0019]

Embodiment 1 FIG. 1 is a cross-sectional view showing a cylindrical non-aqueous battery in which the electrode laminate is a wound type. [Production of positive electrode plate 4] LiCoO ₂ was used as the positive electrode active material.
Was used. A mixture of LiCoO ₂ and flaky graphite as a conductive material mixed at a weight ratio of 100: 5, and a mixture of milafuron (manufactured by Asahi Chemical Industry Co., Ltd.) of ethyl acetate and 2-ethoxyethanol (ethylene glycol monoethyl ether) It was dispersed in a 4.3 wt% milaphron solution dissolved in a solvent to obtain a positive electrode active material dispersion. The positive electrode active material dispersion containing LiCoO ₂ was applied to only one surface of the current collector foil 4a made of aluminum, dried, and the positive electrode active material layer 4b was applied to a thickness of 87 μm.

[Preparation of Negative Electrode Plate 5] A mixture of mesophase pitch carbon fiber graphite and flaky graphite at a weight ratio of 90:10 was used as the negative electrode active material. After dispersing this graphite mixture in a 2.0% aqueous solution of carboxymethylcellulose,
Further, a 4.2 wt% latex aqueous solution was added to obtain a negative electrode active material dispersion such that the ratio of graphite mixture: carboxymethylcellulose: latex = 100: 1: 2. The negative electrode active material slurry is applied to only one side of the current collector foil 5a made of copper and dried to form the negative electrode active material layer 5b with 81%.
It was applied with a thickness of μm.

[Preparation of Insulating Film] α having an average particle size of 1.0 μm
-Al ₂ O ₃ powder and polyvinylidene fluoride (PVDF) powder are mixed in the powder state at a weight ratio of 100: 5, and N-methylpyrrolidone (NMP) is added thereto and further mixed,
A dispersion having a solid content of 56.8% was obtained. This dispersion is uniformly applied to the surface of the current collector foil on the side where the active materials of the positive electrode and the negative electrode are not adhered, and dried at 120 ° C.
The insulating film 7 composed of the aggregate of the insulating material particles was fixed.

[Preparation of Electrode Laminate] The width required for winding the positive electrode 4 and the negative electrode 5 to which the insulating film 7 is fixed (the positive electrode 54 mm,
After cutting into a strip shape of a negative electrode (56 mm), a current extraction terminal was attached, and the two were placed so that the surfaces on which the active materials were attached faced each other. Between them, a separator 6 (width: 58 mm) made of a 34 μm polyethylene microporous film was used. Was wound by a winding machine to obtain a cylindrical electrode laminate 1.

[Preparation of Battery Can] The cylindrical electrode laminate was inserted into a cylindrical metal outer can 2, and the negative electrode current takeout terminal was welded to the metal outer can and the positive electrode current takeout terminal was welded to the lid. . An electrolytic solution obtained by dissolving LiPF ₆ at a concentration of 1 M in a mixed solvent of ethylene carbonate (EC) and diethyl carbonate (DEC) at a volume ratio of 1: 1 was poured into the mixture, sealed, and sealed to a size of 18650 (diameter 18 mm, high 6
(5 mm) cylindrical can battery (Example 1).

As a comparative example, the same cylindrical can battery as in Example 1 (Comparative Example 1) except that the same microporous polyethylene film of 34 μm as the separator was used for the insulating film between the current collector foils.
Was prepared. A cross-sectional view is shown in FIG. [Charge / Discharge Test] A charge / discharge test was performed under the following conditions. 1 cycle charge: 4.2V, 0.5C, 6 hours, constant current constant voltage charge Discharge: 2.7V, 0.5C, constant current discharge 2 cycles charge: 4.2V, 1.0C, 3 hours, constant current Constant voltage charge Discharge: 2.7 V, 1.0 C, constant current discharge 3 cycles Charge: 4.2 V, 1.0 C, 3 hours, constant current constant voltage charge In a charged state, storage at 85 ° C. for 24 hours 3 cycles Discharge: 2.7 V, 1.0 C, constant current discharge 4 cycles Charge: 4.2 V, 1.0 C, 3 hours, constant current constant voltage charge Discharge: 2.7 V, 1.0 C, constant current discharge The results are shown in FIG. .

As shown in FIG. 3, the decrease in the discharge capacity when the high-temperature storage is performed is small in the embodiment.
This is presumed to be due to the fact that by-products and residual moisture in the battery can were adsorbed by the insulating material particles used as the insulating film, thereby reducing the performance degradation of the battery at high temperatures.

[0026]

Example 2 Insulating material particles were used as a separator. [Production of positive electrode plate 4] LiCoO ₂ was used as the positive electrode active material.
Was used. A mixture of LiCoO ₂ and flaky graphite as a conductive material mixed at a weight ratio of 100: 5, and a mixture of milafuron (manufactured by Asahi Chemical Industry Co., Ltd.) of ethyl acetate and 2-ethoxyethanol (ethylene glycol monoethyl ether) It was dispersed in a 4.3 wt% milaphron solution dissolved in a solvent to obtain a positive electrode active material dispersion. The positive electrode active material dispersion containing LiCoO ₂ was applied to only one surface of the current collector foil 4a made of aluminum, dried, and the positive electrode active material layer 4b was applied to a thickness of 87 μm.

[Preparation of Negative Electrode Plate 5] A mixture of mesophase pitch carbon fiber graphite and flaky graphite at a weight ratio of 90:10 was used as the negative electrode active material. After dispersing this graphite mixture in a 2.0% aqueous solution of carboxymethylcellulose,
Further, a 4.2 wt% latex aqueous solution was added to obtain a negative electrode active material dispersion such that the ratio of graphite mixture: carboxymethylcellulose: latex = 100: 1: 2. The negative electrode active material slurry is applied to only one side of the current collector foil 5a made of copper and dried to form the negative electrode active material layer 5b with 81%.
It was applied with a thickness of μm.

[Preparation of Separator] Average particle size 1.0 μm
m-α-Al ₂ O ₃ powder and polyvinylidene fluoride (PVD
F) mixing the powder in a powder state at a weight ratio of 100: 5,
1-Methyl-2-pyrrolidone (NMP) was added thereto and further mixed to obtain a dispersion having a solid content of 56.8%. This dispersion was uniformly applied to the surfaces of the active material layers of the positive electrode and the negative electrode, and dried at 120 ° C. to fix a porous insulating film made of an aggregate of insulating material particles of about 15 μm as a separator 6.

[Preparation of Insulating Film] The same dispersion as that of the separator was uniformly applied to the surface of the current collector foil on the side where the active materials of the positive electrode and the negative electrode were not adhered, and then dried at 120 ° C. Thus, the insulating film 7 composed of an aggregate of insulating material particles of about 15 μm was fixed. [Preparation of Electrode Laminate] The width required for winding the positive electrode plate 4 and the negative electrode plate 5 having the insulating film fixed thereon (positive electrode 56 mm, negative electrode 58 m
m), after cutting into a band shape, attaching a current extraction terminal, and arranging such that both active material-coated surfaces face each other;
It was wound up by a winding machine to obtain a cylindrical electrode laminate 1.

The subsequent steps were performed in the same manner as in Example 1 to obtain a cylindrical can battery (Example 2). A cross-sectional view is shown in FIG. The discharge capacities when the cylindrical battery cans of Example 1, Example 2, and Comparative Example 1 were charged and discharged under the following conditions were as follows: Examples 1: 135
0 mAH, Example 2: 1399 mAH, Comparative Example 1: 13
43 mAH.

Charge / discharge conditions Charge: 4.2 V, 0.5 C, 6 hours, constant current constant voltage charge Discharge: 2.7 V, 0.5 C, constant current discharge As in Example 2, ionic conductivity is required. By using the same aggregate of insulator material particles as the insulating film for the separator part, it is possible to omit the protrusion from the electrode in the width direction, which was always necessary for a separator of an independent film such as a polyolefin microporous film, and the capacity was increased. Was confirmed to be improved.

[0032]

Embodiment 3 [Preparation of Positive Electrode Plate 4] LiCoO ₂ was used as the positive electrode active material.
Was used. A mixture of LiCoO ₂ and flaky graphite as a conductive material mixed at a weight ratio of 100: 5, and a mixture of milafuron (manufactured by Asahi Chemical Industry Co., Ltd.) of ethyl acetate and 2-ethoxyethanol (ethylene glycol monoethyl ether) It was dispersed in a 4.3 wt% milaphron solution dissolved in a solvent to obtain a positive electrode active material dispersion. The positive electrode active material dispersion containing LiCoO ₂ was applied to only one surface of the current collector foil 4a made of aluminum, dried, and the positive electrode active material layer 4b was applied to a thickness of 87 μm.

[Preparation of Negative Electrode Plate 5] A mixture of mesophase pitch carbon fiber graphite and flaky graphite at a weight ratio of 90:10 was used as the negative electrode active material. After dispersing this graphite mixture in a 2.0% aqueous solution of carboxymethylcellulose,
Further, a 4.2 wt% latex aqueous solution was added to obtain a negative electrode active material dispersion such that the ratio of graphite mixture: carboxymethylcellulose: latex = 100: 1: 2. The negative electrode active material slurry is applied to only one side of the current collector foil 5a made of copper and dried to form the negative electrode active material layer 5b with 81%.
It was applied with a thickness of μm.

[Preparation of Insulating Film] α having an average particle size of 1.0 μm
-Al ₂ O ₃ powder and polyvinylidene fluoride (PVDF) powder are mixed in a powder ratio in a weight ratio of 100: 5, 1-methyl-2-pyrrolidone (NMP) is added thereto, and the mixture is further mixed. A dispersion having a fraction of 56.8% was obtained. After uniformly applying the same dispersion liquid as the separator to the surface of the current collector foil on the side where the active material of the negative electrode is not adhered, dried at 120 ° C., and from the aggregate of insulating material particles of about 10 μm. The insulating film 7 was fixed.

[Preparation of Electrode Laminated Body] The width required for winding the positive electrode plate 4 and the negative electrode plate 5 having the insulating film fixed thereon (positive electrode 56 m
m, a negative electrode 58 mm), and a current extraction terminal was attached thereto. The two electrodes were arranged so that their active material-coated surfaces faced each other, and were wound by a winding machine to obtain a cylindrical electrode laminate 1. Obtained.

The subsequent steps were performed in the same manner as in Example 1 to obtain a cylindrical can battery (Example 3). Example 1 of cylindrical battery can,
The discharge capacities when Example 3 was charged and discharged under the following conditions were Example 1: 1350 mAH and Example 3: 1396 mAH. Charge / discharge conditions Charge: 4.2 V, 0.5 C, 6 hours, constant current / constant voltage charge Discharge: 2.7 V, 0.5 C, constant current discharge As in Example 3, an insulating material particle aggregate as an insulating film By using, the thickness of the insulating film can be reduced to a thickness that cannot be achieved by a separator having an independent membrane such as a microporous polyolefin membrane, and thus the length of an electrode that can be accommodated in a battery can of the same size can be increased. Therefore, in Example 3, it was confirmed that the capacity was improved as compared with Example 1. By using the insulating material particle aggregate as the separator as in Example 2, the thickness of the separator between the active material layers can be reduced, and the capacity can be further improved.

[0037]

Example 4 [Preparation of positive electrode plate 4] LiMn ₂ O ₄ was used as the positive electrode active material.
Was used. A mixture of LiMn ₂ O ₄ , flaky graphite as a conductive material in a weight ratio of 100: 5, and PVD
The F powder was mixed at a weight ratio of 100: 5, NMP was added, and the mixture was further mixed and dispersed to obtain a positive electrode active material dispersion. LiMn _{2 is provided} on only one side of the current collector foil 4a made of aluminum.
A positive electrode active material dispersion containing O ₄ was applied and dried, and a positive electrode active material layer 4b was applied to a thickness of 99 μm.

The subsequent steps were performed in the same manner as in Example 1 to produce a cylindrical can battery (Example 3). As a comparative example, a cylindrical can battery (Comparative Example 2) was produced in the same manner as in Example 4 except that the same microporous polyethylene film of 34 μm as the separator was used for the insulating film between the current collector foils. FIG. 2 is a cross-sectional view. [Charge / Discharge Test] A charge / discharge test was performed under the following conditions. 1 cycle charge: 4.2V, 0.5C, 6 hours, constant current constant voltage charge Discharge: 2.7V, 0.5C, constant current discharge 2 cycles charge: 4.2V, 1.0C, 3 hours, constant current Constant voltage charge Discharge: 2.7 V, 1.0 C, constant current discharge 3 cycles Charge: 4.2 V, 1.0 C, 3 hours, constant current constant voltage charge In a charged state, storage at 85 ° C. for 24 hours 3 cycles Discharge: 2.7V, 1.0C, constant current discharge, 4 cycles Charge: 4.2V, 1.0C, 3 hours, constant current, constant voltage charge Discharge: 2.7V, 1.0C, constant current discharge The results are shown in FIG. .

As shown in FIG. 5, the decrease in the discharge capacity when the high-temperature storage is performed is small in the embodiment.
This is presumed to be due to the fact that by-products and residual moisture in the battery can were adsorbed by the insulating material particles used as the insulating film, thereby reducing the performance degradation of the battery at high temperatures. Furthermore, comparing the difference between Example 1 and Comparative Example 1 and the difference between Example 4 and Comparative Example 2, the latter is larger, and LiMn is used as the positive electrode.
It can be seen that the effect of improving the performance of high-temperature storage is great for a battery using 2O4.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a cylindrical non-aqueous battery in which an electrode laminate is a wound type using an insulating material particle aggregate as an insulating film as shown in Example 1 of the present invention. is there.

FIG. 2 is a cross-sectional view showing a cylindrical non-aqueous battery having a wound electrode stack using a conventional polyolefin microporous film as an insulating film, as in Comparative Example 1.

FIG. 3 is a graph showing a change in discharge capacity in Example 1 and Comparative Example 1.

FIG. 4 is a cross-sectional view showing a cylindrical non-aqueous battery in which an electrode laminate is a wound type using insulating material particles for an insulating film and a separator as in Example 2.

FIG. 5 is a graph showing a change in discharge capacity in Example 3 and Comparative Example 2.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electrode laminated body 2 Outer can 3 Unit battery layer 4 Positive electrode plate 4a Positive electrode current collector foil 4b Positive electrode active material layer 5 Negative electrode plate 5a Negative electrode current collector foil 5b Negative electrode active material layer 6 Separator 7 Insulating film 7a Negative electrode current collector Fixed insulating film 7b Insulating film fixed to positive electrode current collector

Claims (1)

[Claims] 1. A positive electrode plate having a positive electrode active material deposited on only one side of a current collector foil and a negative electrode plate having a negative electrode active material deposited on only one side of a current collector foil are composed of active material layers. Are disposed so as to face each other, and in a nonaqueous battery provided with a separator interposed therebetween, at least one of the current collector foils of the positive electrode plate and the negative electrode plate, on one surface on the side where the active material layer is not adhered. A non-aqueous battery, wherein an insulating film made of an aggregate of insulating material particles is fixed.