JP2000030686A - Non-aqueous electrolyte battery separator and lithium secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a safe battery with a high shorting temperature by using a separator containing a base material made of fabric, nonwoven fabric, paper or porous film, heat resistant nitrogen-containing aromatic polymer, and ceramic powder. SOLUTION: A base material contains organic fiber and/or inorganic fiber and is 40 g/m2 or less in weight per a unit area and 70 μm or less in thickness. Organic fiber is formed of thermoplastic polymer, while inorganic fiber is made of glass fiber. A separator contains 10 weight % or more of thermoplastic polymer melting at 260 deg.C or less, and the thermoplastic polymer is melted according to the increase of temperature so as to close cavities in the separator. Heat resistant nitrogen-containing aromatic polymer is aromatic polyimide or aromatic polyamide, while ceramic powder is metal oxide metal nitride, or metal carbide with a primary mean grain size of 1.0 μm or less. A slurry solution, in which ceramic powder is dispersed in a polar organic solvent solution containing heat resistant nitrogen-containing aromatic polymer, is prepared so as to be applied to the base material and dried then.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a non-aqueous electrolyte battery separator containing a heat-resistant nitrogen-containing aromatic polymer and ceramic powder, and a lithium secondary battery.

[0002]

2. Description of the Related Art A lithium primary battery or a lithium secondary battery using a non-aqueous electrolyte is expected to have high capacity and high energy density. In these batteries, a separator made of an electrically insulating porous film is interposed between positive and negative electrodes, and an electrolyte solution in which a lithium salt is dissolved is impregnated in the gaps of the film, and the positive and negative electrodes and the separator are separated. Are mainly laminated or spirally wound. Lithium secondary batteries require various safety measures against problems due to their high capacity and high energy density, for example, a large rise in battery temperature due to short circuits inside and outside the batteries. In order to solve such problems, attempts have been made to add various devices to the separator.

[0003] In particular, as safety measures to which a separator can contribute, attention has been paid to shutdown characteristics and short-circuit characteristics. Here, when the battery temperature rises due to troubles such as overcharging or external or internal short circuit, a part of the separator melts, the void is closed, and the current is cut off is called a shutdown (also called a fuse). This temperature is called the shutdown temperature. When the temperature rises further, the separator melts, a large hole is formed, and a short circuit occurs again, a short circuit is called, and the temperature at that time is called a short temperature. It is required for a separator for a non-aqueous electrolyte battery to have a low shutdown temperature and a high short temperature.

Conventionally, a porous film having a small thickness has been used as a separator for a lithium secondary battery.
For example, Celgard (registered trademark) manufactured by Hoechst is preferably used as a separator of a lithium secondary battery. However, a separator for a non-aqueous electrolyte battery having better heat resistance and a higher short-circuit temperature has been desired.

As a material for such a separator for a non-aqueous electrolyte battery, the use of a wholly aromatic polyamide polymer having excellent heat resistance has been studied. For example, Japanese Patent Publication No. 59-36939 describes a method for producing a porous film of an aromatic polymer, an aromatic polyamide and an aromatic polyimide, and Japanese Patent Publication No. 59-14494 discloses an aromatic polyamide. And a method for producing a porous film, which can be used as a battery separator. Further, Japanese Patent Application Laid-Open No. 5-33500
No. 5 describes that Nomex (registered trademark) paper (metaramid paper) manufactured by du Pont is used as a separator of a lithium secondary battery. Similarly, JP-A-7-78608 and JP-A-7-3775
No. 1 also discloses that a non-woven fabric or paper-like sheet made of meta-aramid is used for a battery separator. For polyimide, see JP-A-62-3
No. 7871 and Japanese Patent Application Laid-Open No. 2-46649 describe the use of the polymer as a separator for a non-aqueous electrolyte battery. With respect to these, it has been demanded that those having good ion permeability and good battery characteristics be maintained while maintaining heat resistance.

On the other hand, from the viewpoint of the shutdown characteristics and the short-circuit characteristics, Japanese Patent Application Laid-Open Nos. 3-291848 and 4-1692 disclose that in the event of a short circuit inside and outside the battery, the safety of the battery is ensured. A sealing material that can be heated and melted is attached to the porous film of the thermoplastic resin, and the sealing material is heated and melted to cover the surface of the microporous membrane, thereby providing the battery separator with a shutdown function of interrupting current. It has been proposed. Also, JP-A-60-52 and JP-A-60-136161 disclose a polyethylene-based resin powder adhered to a polypropylene non-woven fabric, and the powder is heated and melted to close the holes of the non-woven fabric. It has been proposed to have a shutdown function in the CAM. However, all of them use a thermoplastic resin, have insufficient heat resistance, are low in short-circuit temperature, and are limited in use in terms of safety. The present inventors have conducted intensive studies on a separator having no problems as described above, and as a result, a separator containing ceramic powder in a heat-resistant nitrogen-containing aromatic polymer has a high heat resistance and a high short-circuit temperature. It was also found that the ion permeability was good.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to make use of the features of a heat-resistant nitrogen-containing aromatic polymer having high heat resistance and a high short-circuit temperature, and to further improve the ion permeability and the battery characteristics. An object of the present invention is to provide a separator for a water electrolyte battery.

Another object of the present invention is to provide a separator for a non-aqueous electrolyte battery which has the safety of shutting down when overheated, does not melt even when heated, has a high short-circuit temperature, and is excellent in safety. It is in. Still another object of the present invention is to provide a lithium secondary battery having a high short-circuit temperature and excellent safety by using the separator.

[0009]

That is, the present invention provides (1)
The present invention relates to a non-aqueous electrolyte battery separator containing a heat-resistant nitrogen-containing aromatic polymer and ceramic powder.

[0010] The present invention also relates to (2) a non-aqueous electrolyte battery separator comprising a substrate made of woven fabric, nonwoven fabric, paper or a porous film, a heat-resistant nitrogen-containing aromatic polymer and ceramic powder.

Next, the present invention provides (3) a separator for a non-aqueous electrolyte battery, which contains at least 10% by weight of a thermoplastic polymer which melts at 260 ° C. or less, based on the entire separator;
The thermoplastic polymer is a polymer that melts when the temperature rises and closes the voids of the separator, and relates to the nonaqueous electrolyte battery separator according to (1) or (2).

Further, the present invention provides (4)
The present invention relates to a non-aqueous electrolyte battery separator comprising a coating film produced by a method including the step (e). (A) In a polar organic solvent solution containing a heat-resistant nitrogen-containing aromatic polymer, 1 to 1500 parts by weight of a ceramic powder is dispersed with respect to 100 parts by weight of the heat-resistant nitrogen-containing aromatic polymer.
Prepare a slurry solution that may contain a thermoplastic resin that melts at or below 0 ° C. (B) applying the slurry solution to form a coating film. (C) depositing the heat-resistant nitrogen-containing aromatic polymer on the coating film. (D) removing the polar organic solvent from the coating film; (E) drying the coated film;

Next, the present invention provides (5)
The present invention relates to a non-aqueous electrolyte battery separator comprising a coating film produced by a method including the step (e). (A) In a polar organic solvent solution containing a heat-resistant nitrogen-containing aromatic polymer, 1 to 1500 parts by weight of a ceramic powder is dispersed with respect to 100 parts by weight of the heat-resistant nitrogen-containing aromatic polymer.
Prepare a slurry solution that may contain a thermoplastic resin that melts at or below 0 ° C. (B) The slurry solution is applied to a substrate made of woven fabric, nonwoven fabric, paper or a porous film to form a coated film. (C) depositing the heat-resistant nitrogen-containing aromatic polymer on the coating film. (D) removing the polar organic solvent from the coating film; (E) drying the coated film;

Further, the present invention provides (6) the present invention (1) to
It relates to a lithium secondary battery including the nonaqueous electrolyte battery separator according to (5).

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. The non-aqueous electrolyte battery separator of the present invention is characterized by containing a heat-resistant nitrogen-containing aromatic polymer and ceramic powder.

The heat-resistant nitrogen-containing aromatic polymer in the present invention is a polymer having a main chain containing a nitrogen atom and an aromatic ring,
For example, aromatic polyamide (hereinafter, sometimes referred to as “aramid”), aromatic polyimide (hereinafter, “polyimide”)
In some cases) and aromatic polyamideimide.

The aramid includes, for example, a meta-oriented aromatic polyamide (hereinafter, sometimes referred to as “meta-aramid”) and a para-oriented aromatic polyamide (hereinafter, sometimes referred to as “para-aramid”). Para-aramid is preferred because of its ease.

Here, the para-aramid is obtained by condensation polymerization of a para-oriented aromatic diamine and a para-oriented aromatic dicarboxylic acid halide, and the amide bond has a para-position of an aromatic ring or an alignment position similar thereto (for example, 4,
It consists essentially of recurring units linked in opposite directions, such as 4'-biphenylene, 1,5-naphthalene, 2,6-naphthalene, etc.).

Specifically, poly (paraphenylene terephthalamide), poly (parabenzamide, poly (4,
4'-benzanilide terephthalamide), poly (paraphenylene-4,4'-biphenylenedicarboxylic acid amide), poly (paraphenylene-2,6-naphthalenedicarboxylic acid amide), poly (2-chloro-paraphenylene terephthalamide) And para-aramid having a para-oriented or para-oriented structure such as paraphenylene terephthalamide / 2,6-dichloroparaphenylene terephthalamide copolymer.

The para-aramid in the present invention can be dissolved in a polar organic solvent to form a low-viscosity solution, and is excellent in coating properties, so that para-aramid having an intrinsic viscosity of 1.0 dl / g to 2.8 dl / g may be used. Preferably, the intrinsic viscosity is 1.7 dl / g to 2.5 dl / g.
If the intrinsic viscosity is less than 1.0 dl / g, sufficient film strength may not be obtained. 2.8 dl intrinsic viscosity
/ G is difficult to become a stable para-aramid solution,
In some cases, para-aramid precipitates and it is difficult to form a film.

Here, the polar organic solvent is, for example, a polar amide-based solvent or a polar urea-based solvent. Specifically, N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-methyl-2-amide Examples include, but are not limited to, pyrrolidone and tetramethylurea.

The para-aramid in the present invention is porous and is preferably a fibril-like polymer. The fibril-like polymer is microscopically non-woven, has layered and porous voids, and forms a so-called para-aramid porous resin.

The polyimide used in the present invention includes:
A wholly aromatic polyimide produced by condensation polymerization of an aromatic dianhydride and a diamine is preferred. Specific examples of the dianhydride include pyromellitic dianhydride, 3, 3 ′, 4, 4 ′
-Diphenylsulfonetetracarboxylic dianhydride, 3,
3 ', 4,4'-benzophenonetetracarboxylic dianhydride, 2,2'-bis (3,4-dicarboxyphenyl) hexafluoropropane, 3,3', 4,4'-biphenyltetracarboxylic dianhydride Anhydrides and the like.
Specific examples of the diamine include oxydianiline, paraphenylenediamine, benzophenone diamine, 3,
3′-methylenedianiline, 3,3′-diaminobensophenone, 3,3′-diaminodiphenylsulfone,
Examples thereof include 1,5′-naphthalenediamine, but the present invention is not limited to these. In the present invention, when a porous film is prepared directly from a polyimide solution, a solvent-soluble polyimide can be suitably used. As this polyimide, for example, 3,
Examples of the polyimide include a polycondensate of 3 ′, 4,4′-diphenylsulfonetetracarboxylic dianhydride and an aromatic diamine.

As the polar organic solvent used for polyimide, in addition to those exemplified for aramid, dimethyl sulfoxide, cresol, o-chlorophenol and the like can be suitably used.

In the present invention, the polyimide is preferably a porous one. For example, a solid film can be made porous by drilling by machining or laser processing. When a polyimide film is prepared by a solution casting method, a porous film can be prepared by controlling polyimide molding conditions such as a polymer concentration at the time of coating. Further, by forming a composite of the ceramic powder, a uniform and fine porous material can be formed with a solution having an arbitrary polymer concentration. The air permeability can be controlled by the amount of the ceramic powder added.

The separator for a non-aqueous electrolyte battery of the present invention needs to contain ceramic powder. The ceramic powder is trapped by being entangled with the heat-resistant nitrogen-containing aromatic polymer, and is disposed in whole or in part in the non-aqueous electrolyte battery separator.

The average particle size of the primary particles of the ceramic powder in the present invention is preferably 1.0 μm or less, from the viewpoint of the effect on the strength of the separator for nonaqueous electrolyte batteries and the smoothness of the coated surface. The powder is more preferably the following powder, and further preferably 0.1 μm or less. The average particle size of the primary particles is measured by a method in which a photograph obtained by an electron microscope is analyzed by a particle size measuring device. Average primary particle size of ceramic powder is 1.0μm
When it exceeds, the separator may be brittle and the coated surface may be rough. Further, the content of the ceramic powder is preferably 1% of the weight of the separator for a non-aqueous electrolyte battery.
% By weight to 95% by weight, more preferably 5% by weight or less.
% By weight or more and 50% by weight or less. The content of ceramic powder is 1% by weight of the separator weight for non-aqueous electrolyte batteries
If it is less than 95%, the effect of promoting ion permeability and battery characteristics may not be sufficient, and if it exceeds 95% by weight, the separator may become brittle and difficult to handle. The shape of the ceramic powder is not particularly limited,
Spherical or random shapes can be used.

As the ceramic powder in the present invention,
Ceramic powders composed of electrically insulating metal oxides, metal nitrides, metal carbides, and the like can be used. For example, powders of alumina, silica, titanium dioxide, zirconium oxide, and the like are preferably used. The above ceramic powders may be used alone or as a mixture of two or more.

The substrate in the present invention includes porous woven fabric, non-woven fabric, paper or porous film made of electrically insulating organic or inorganic fibers or pulp. In view of the above, a nonwoven fabric, paper or a porous film is preferred.

The material of the substrate may be an organic or inorganic material as long as it is electrically insulating, and may be a synthetic or natural material. The substrate may be made of organic fiber and / or inorganic fiber and / or organic fiber pulp. And / or inorganic fiber pulp. Specifically, examples of the organic fibers include fibers made of a thermoplastic polymer and natural fibers such as manila hemp. Examples of the fiber made of the thermoplastic polymer include polyolefin such as polyethylene and polypropylene, and fiber such as rayon, vinylon, polyester, acryl, polystyrene, and nylon. Examples of the inorganic fibers include glass fibers and alumina fibers.

The separator for a non-aqueous electrolyte battery according to the present invention (2) is characterized by comprising a substrate made of woven fabric, non-woven fabric, paper or porous film, a heat-resistant nitrogen-containing aromatic polymer and ceramic powder. .

The separator for a non-aqueous electrolyte battery of the present invention (2) is obtained by coating the substrate with a heat-resistant nitrogen-containing aromatic polymer containing the above-mentioned ceramic powder, or by forming a void in the substrate. A heat-resistant nitrogen-containing aromatic polymer is filled, or the substrate is coated with the heat-resistant nitrogen-containing aromatic polymer, and the voids of the substrate are filled with the heat-resistant nitrogen-containing aromatic polymer. Filled ones are preferred.

When used in the separator for a non-aqueous electrolyte battery of the present invention (2), the weight per unit area of the substrate is as follows:
It is preferably 40 g / m ² or less, more preferably 15 g / m ² or less.
/ M ² or less. The porosity of the substrate is preferably 40% or more, more preferably 50% or more. The thickness of the substrate is preferably 70 μm or less,
More preferably, it is 25 μm or less.

The separator for a non-aqueous electrolyte battery according to the present invention (3) has a temperature of 260 ° C.
10% by weight or more, preferably 30% by weight or more, more preferably 40% by weight
This is characterized in that the thermoplastic polymer melts when the temperature rises and closes the voids of the separator. When the thermoplastic polymer is used for a battery separator used in the present invention, any thermoplastic polymer may be used as long as it melts when the temperature is raised. When used as a separator of a lithium secondary battery, the thermoplastic polymer is preferably a polymer that melts at 260 ° C. or lower, and more preferably 200 ° C. or lower, from the viewpoint of a shutdown function. The melting temperature is preferably about 100 ° C. or more because it is appropriate as a shutdown temperature.

Examples of the thermoplastic polymer include polyolefin resin, acrylic resin, styrene resin, polyester resin and nylon resin. In particular, polyethylene such as low-density polyethylene, high-density polyethylene, linear polyethylene, or a low-molecular-weight wax thereof, or a polyolefin resin such as polypropylene is suitably used because it has an appropriate melting temperature and is easily available. These can be used alone or in combination of two or more.

The thermoplastic polymer used in the present invention is preferably a powder having an average particle diameter of preferably 10 μm or less, more preferably 6 μm or less, from the viewpoint of dispersibility in a solvent and smoothness of a coated surface. The shape of the powder particles is not particularly limited, and may be spherical or random.

In the separator for a non-aqueous electrolyte battery of the present invention (3), the thermoplastic polymer is dispersed in the whole or part of the separator for a non-aqueous electrolyte battery in a particle form. There is no particular limitation as long as the thermoplastic polymer melts when the temperature rises and closes the voids in the separator.

Further, the separator for a non-aqueous electrolyte battery of the present invention (4) comprises a coating film produced by a method comprising the following steps (a) to (e). (A) In a polar organic solvent solution containing a heat-resistant nitrogen-containing aromatic polymer, 1 to 1500 parts by weight of a ceramic powder is dispersed with respect to 100 parts by weight of a heat-resistant nitrogen-containing aromatic polymer.
The following prepares a slurry solution that may contain a thermoplastic resin that melts. (B) applying the slurry solution to form a coating film. (C) depositing the heat-resistant nitrogen-containing aromatic polymer on the coating film. (D) removing the polar organic solvent from the coating film; (E) drying the coated film;

Hereinafter, the method for producing the separator for a non-aqueous electrolyte battery of the present invention (4) will be specifically described. Step (a) Preparation of Slurry Solution A case where para-aramid and polyimide are used as the heat-resistant nitrogen-containing aromatic polymer will be exemplified.

When para-aramid is used, for example,
2 to 1 chloride of alkali metal or alkaline earth metal
In a polar organic solvent in which 0% by weight is dissolved, 0.94 to 0.99 mol of para-oriented aromatic dicarboxylic acid dihalide is added to 1.00 mol of para-oriented aromatic diamine, and the temperature is -20 ° C to 50 ° C. The para-oriented aromatic polyamide produced by condensation polymerization at a concentration of 1 to 10% and an intrinsic viscosity of 1.0
Make a solution of aramid in polar organic solvent that is ~ 2.8 dl / g.

As the para-oriented aromatic diamine used in the condensation polymerization of para-aramid, para-phenylenediamine,
4,4′-diaminobiphenyl, 2-methyl-paraphenylenediamine, 2-chloro-paraphenylenediamine, 2,6-dichloro-paraphenylenediamine, 2,
Examples thereof include 6-naphthalenediamine, 1,5-naphthalenediamine, 4,4′-diaminobenzanilide, and 3,4′-diaminodiphenyl ether. The para-oriented aromatic diamine can be used for condensation polymerization by mixing one kind or two or more kinds.

Examples of the para-oriented aromatic dicarboxylic acid dihalide used in the condensation polymerization of para-aramid include terephthalic acid dichloride, biphenyl-4,4'-dicarboxylic acid dichloride, 2-chloroterephthalic acid dichloride,
2,5-dichloroterephthalic acid dichloride, 2-methylterephthalic acid dichloride, 2,6-naphthalenedicarboxylic acid dichloride, 1,5-naphthalenedicarboxylic acid dichloride and the like can be mentioned. The para-oriented aromatic diamine can be used for condensation polymerization by mixing one kind or two or more kinds.

In order to improve the solubility of para-aramid in a solvent, an alkali metal or alkaline earth metal chloride is preferably used. Specific examples include, but are not limited to, lithium chloride or calcium chloride.

The amount of the chloride to be added to the polymerization system is 0.5 to 6.0 per 1.0 mol of the amide group formed in the condensation polymerization.
The mole range is preferred, and the range of 1.0 to 4.0 moles is more preferred. When the amount of chloride is less than 0.5 mol, the solubility of the produced para-aramid may be insufficient, and
If the amount exceeds 0 mol, the amount of chloride substantially dissolves in the solvent, which may not be preferable.

In general, if the alkali metal or alkaline earth metal chloride is less than 2% by weight, the solubility of para-aramid may be insufficient, and if it exceeds 10% by weight, the alkali metal or alkaline earth metal may be insufficient. May not be dissolved in polar organic solvents such as polar amide solvents or polar urea solvents.

If the para-aramid concentration is less than 0.5% by weight, the productivity may be remarkably reduced, which may be industrially disadvantageous. If the amount of para-aramid exceeds 10% by weight, para-aramid may precipitate, and it may be difficult to obtain a stable para-aramid solution.

Examples of the solution of polyimide in a polar organic solvent include 3,3 ′, 4,4′-diphenylsulfonetetracarboxylic dianhydride and 4,4′-bis (p-
N-methyl-2-pyrrolidone solution of a polyimide which has been completely imidized and obtained by a polycondensation reaction with an aromatic diamine such as aminophenyl) diphenylsulfone. When polyimide is used as the polar organic solvent, in addition to the above-mentioned examples, cresol, or o
-Chlorophenol and the like.

In the above polar organic solvent solution, 1 to 100 parts by weight of the heat-resistant nitrogen-containing aromatic polymer was mixed with the ceramic powder.
1500 parts by weight, preferably 5 to 100 parts by weight, are sufficiently dispersed to prepare a slurry solution. If the amount of the ceramic powder is less than 1 part by weight, the ion permeability and battery characteristics are not sufficiently improved, and if it exceeds 1500 parts by weight, the separator becomes brittle and difficult to handle, which is not preferable. If necessary, a thermoplastic polymer may be added to the slurry solution.

Step (b) Preparation of Coated Film This slurry solution was applied to a base film, steel belt,
Coating on rolls, drums, etc. to form a wet coating film. Examples of the base film include polyethylene terephthalate, release-treated paper, and the like. Also,
Coating on a mirror-finished corrosion-resistant steel belt is also often used industrially. On a small scale, it can also be applied on a mirror-finished, corrosion-resistant roll or drum.

Examples of the coating method include a knife, blade, bar, gravure, die and the like. On a small scale, coating with a bar, knife or the like is simple, but industrially, die coating having a structure in which the solution does not come into contact with the outside air is preferable.

Step (c) Precipitation of a Heat-Resistant Nitrogen-Containing Aromatic Polymer The obtained coating film is subjected to the heat-resistant nitrogen-containing aromatic polymer preferably in an atmosphere controlled at a temperature of 20 ° C. or more and a constant humidity. Precipitate and then immerse in the coagulation liquid. Alternatively, the polymer is immersed in a coagulation liquid to simultaneously precipitate and coagulate the polymer to obtain a wet coating film. In order to carry out the precipitation uniformly and quickly, a poor solvent, for example, water or the like may be added to the slurry solution in advance to make the slurry solution.

In the case of para-aramid, a part or all of the solvent is evaporated and the polymer is precipitated at the same time, that is, the subsequent solvent removal step and the precipitation step are simultaneously performed to obtain a semi-dried or dried coating film. .

As the coagulation liquid used herein, an aqueous solution or an alcoholic solution may be used, and it is not particularly limited, but an aqueous solution or an alcoholic solution containing a polar organic solvent solvent is industrially used. This is preferable because the solvent recovery step is simplified. Specifically, an aqueous solution of a polar organic solvent can be used.

Step (d) Removal of Polar Organic Solvent Next, the polar organic solvent is removed from the coating film on which the heat-resistant nitrogen-containing aromatic polymer has been deposited. As for the method of removal, a part or the whole may be evaporated, or the solvent may be removed with a solvent capable of dissolving a polar organic solvent such as water, an aqueous solution, or an alcohol solution. When removing with water, it is preferable to use ion-exchanged water. It is also industrially preferable to further wash with water after washing in an aqueous solution containing a constant concentration of a polar organic solvent. Drying is performed by evaporating a solvent for washing by heating. The drying temperature at this time is preferably equal to or lower than the melting temperature when containing a melting thermoplastic polymer.

When para-aramid is prepared using an alkali metal or alkaline earth metal chloride,
From the wet coating film on which para-aramid is deposited, wash the alkali metal or alkaline earth metal chloride with the solvent,
Remove. Alternatively, the alkali metal or alkaline earth metal chloride is washed and removed from the dried coating film. As this removing method, a method of immersing the coating film in a solution to elute the solvent and chloride is adopted. As a solution for eluting the solvent or the chloride, water, an aqueous solution, or an alcohol-based solution is preferable because both the solvent and the chloride can be dissolved.

(E) Drying The coating film from which the polar organic solvent has been removed is preferably dried at a temperature not higher than the melting temperature of the polymer to be heated and melted, so that a desired dry coating film can be produced.

The dried coating film can be used as it is as a separator for a non-aqueous electrolyte battery. From the viewpoint of imparting shutdown performance, it is preferable to include a thermoplastic polymer, but it may be included in any step. Further, it is preferable to further apply a fine-grained suspension of a thermoplastic polymer to the dried coating film, dry the coating, and provide a fine particle layer of a thermoplastic resin.

Examples of the coating method include a knife, blade, bar, gravure, die and the like.
On a small scale, coating with a bar, knife, etc. is simple.

The separator for a non-aqueous electrolyte battery of the present invention (5) uses a coating film produced by a method including the following steps (a) to (e). (A) In a polar organic solvent solution containing a heat-resistant nitrogen-containing aromatic polymer, 1 to 1500 parts by weight of a ceramic powder is dispersed with respect to 100 parts by weight of a heat-resistant nitrogen-containing aromatic polymer. Prepare a slurry solution that may include a resin. (B) The slurry solution is applied to a substrate made of woven fabric, nonwoven fabric, paper or a porous film to form a coated film. (C) depositing the heat-resistant nitrogen-containing aromatic polymer on the coating film. (D) removing the polar organic solvent from the coating film; (E) drying the coated film;

Hereinafter, the method for producing the separator for a non-aqueous electrolyte battery of the present invention (5) will be specifically described.

The separator for a non-aqueous electrolyte battery of the present invention (5) can be produced by the same method as that of the present invention (4) except that a substrate made of woven fabric, nonwoven fabric, paper or a porous film is used. Step (a) is the same as step (a) of the present invention (4).
Is the same as The step (b) is the same as the step (b) of the present invention (4) except that the step (b) is applied to a substrate made of a woven fabric, a nonwoven fabric, a paper or a porous film. Alternatively, the slurry solution may be applied on a roll or a drum, and then the substrate may be impregnated with the substrate.

Steps (c), (d) and (e) can be carried out in the same manner as steps (c), (d) and (e) of the present invention (4).

The dried coating film can be used as it is as a separator for a non-aqueous electrolyte battery. From the viewpoint of imparting or reinforcing the shutdown performance, it is preferable to include a thermoplastic polymer, but it may be included in any step. Further, it is preferable to further apply a fine-grained suspension of a thermoplastic polymer to the dried coating film, dry the coating, and provide a fine particle layer of a thermoplastic resin. The coating method is the same as the method of the present invention (4).

The thickness of the separator for a non-aqueous electrolyte battery of the present invention is preferably 5 to 100 μm. If the thickness is less than 5 μm, the strength may be insufficient as a separator for a non-aqueous electrolyte battery and handling may be difficult. As a separator for a non-aqueous electrolyte battery, the thicker it is easier to handle, but for nickel-cadmium batteries there are not so many restrictions, but for lithium secondary batteries the internal resistance is as small as possible, in order to minimize the internal resistance Separation
Tar is desirable. That is, in the separator for a lithium secondary battery, the thickness is preferably 5 to 100 μm, more preferably 5 to 50 μm, and particularly preferably 5 to 30 μm.
It is.

It is known that the heat-resistant nitrogen-containing aromatic polymer used in the present invention has almost no strength deterioration up to a normal temperature of about 200 ° C. and is excellent in heat resistance. In addition, it is self-extinguishing and maintains its form without being thermally decomposed up to about 300 ° C., and is thermally decomposed at a higher temperature. Further, it is known that ceramic powder hardly deteriorates in strength up to about 1000 ° C. and is excellent in heat resistance. Therefore, the non-aqueous electrolyte battery using the separator of the present invention, even if the battery temperature rises due to a short circuit inside and outside the battery, the shutdown function operates, and, even if the temperature further rises, the form is maintained at a high temperature, That is, the insulation between the positive and negative electrodes is maintained, and the safety is particularly excellent.

The size of the voids of the separator for a non-aqueous electrolyte battery of the present invention, or when the voids can be approximated to a sphere, the diameter of the sphere (hereinafter sometimes referred to as the pore diameter) is 1 μm.
m or less is preferable. If the average size or pore diameter of the voids exceeds 1 μm, there is a possibility that a problem such as a short circuit is likely to occur when carbon powder or a small piece thereof as a main component of the positive electrode or the negative electrode falls off.

The separator for a non-aqueous electrolyte battery of the present invention can be suitably used for a lithium secondary battery.
Since the separator for a non-aqueous electrolyte battery of the present invention contains a heat-resistant nitrogen-containing aromatic polymer and ceramic powder, the separator for a non-aqueous electrolyte battery maintains a film shape even when the temperature is increased. Furthermore, when the separator for a non-aqueous electrolyte battery of the present invention containing a thermoplastic resin is used, when the temperature of the battery is locally or entirely increased, the thermoplastic polymer is melted, and the pores of the separator are filled into the pores. It penetrates and seals the micropores so that no current flows. Further, even when the temperature rises, it does not flow out because it enters not the surface but the micropores. In this way, the battery is shut down.

[0068]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. Test / evaluation methods or criteria in Examples and Comparative Examples are as follows.

(1) Intrinsic Viscosity In the present invention, the intrinsic viscosity is defined by the following measuring method. For a solution in which 0.5 g of the para-aramid polymer was dissolved in 100 ml of 96-98% sulfuric acid and for a 96-98% sulfuric acid, the flow time was measured at 30 ° C. using an Ubbelohde capillary viscometer, and the ratio of the flow times was determined. The intrinsic viscosity was determined by the following equation. Intrinsic viscosity = ln (T / T ₀ ) / C [unit: dl / g] where T and T ₀ are the flow times of the para-aramid sulfate solution and sulfuric acid, respectively, and C is the concentration of para-aramid in the para-aramid sulfate solution ( dl / g).

(2) Measurement of Thickness of Coated Film and the Like The thickness of the obtained coated film and the like is measured in accordance with JIS K7130-
1992.

(3) Porosity The coating film or the like was cut into a square having a side length of 10 cm, and the weight (Wg) and thickness (Dcm) were measured. The weight of the material in the sample was divided by calculation, the weight (Wi) of each material was divided by the true specific gravity, and the porosity (vol%) was determined from the following equation, assuming the volume of each material. Porosity (%) = 100 − ｛(W1 / true specific gravity 1) + (W2 /
True specific gravity 2) + .. + (Wn / true specific gravity n)｝ / (100 ×
D)

[0072]

(Equation 1)

The basis weight of the coating film is 10 cm
It was cut out into a square with a corner, and its weight was measured and determined by the following equation. Weight of coating film (g / m ² ) = weight of sample (g)
/0.01 (m ² ) The basis weight of each material was calculated from the amount and ratio used for film formation.

(4) Air permeability Measured area according to ASTM F316-86.
A sample having a size of 3 cm ² (diameter 38 mm) was collected from Porous Materials Inc.
The air flow rate (cc / sec) was measured by measuring the flow rate of air at a pressure of 3 kg / cm ² using m Porometer. In general, in the same material system, if the air permeability is large, it can be determined that the ion permeability is good and the battery characteristics are also good.

(5) Tensile strength A test piece was punched out from the obtained coating film or the like with a dumbbell cutter manufactured by Dumbbell Co., Ltd.
The tensile strength, elastic modulus and strain at break were determined according to 7127.

(6) Measurement of tear strength JIS K-7128-1 manufactured by Dumbbell Co., Ltd.
A test piece was punched out with a dumbbell cutter for the 991 C method (right angle tearing method), and JIS was used using an Instron universal tensile tester model 4301 manufactured by Instron Japan.
The tear strength was measured according to the K-7128-1991 C method (right angle tearing method). Both ends of the sample were gripped by a chuck of a universal tensile tester, pulled at a speed of 200 mm / min, and the load and displacement at that time were recorded by a recorder.
The tear strength was determined from the load at which the sample was torn. Thereafter, the tear propagation resistance was determined from the average value of the load until the sample was completely broken. The tear strength and the tear propagation resistance were determined by the following equations. Tear strength (kg / mm) = Maximum load when sample tearing started / Sample thickness Tear propagation resistance (kg / mm) = Average value of load from start of sample tearing until complete breakage / Sample thickness

(7) Measurement of the internal electric resistance of the flat battery (for the purpose of measuring the electric resistance of the separator, evaluating the shutdown operation, and evaluating the heat resistance) The coating film or the like is formed into a square having a side length of 25 mm. Cut, L
An electrolyte of a 1N propylene carbonate solution of iPF ₆ was impregnated. This is 0.5mm thick, 18mm diameter 2
Between the electrodes of a platinum disc, 1K between the electrodes
The internal electric resistance of the flat battery was measured by applying a voltage of 1 volt at Hz, and the internal electric resistance at 25 ° C. was defined as the electric resistance of the separator. The flat battery was placed on a hot plate, and the temperature was raised from 25 ° C to 200 ° C at a rate of 4 ° C / min. The temperature at which the internal electric resistance increases in this process is defined as the shutdown operating temperature.

(8) Evaluation as Separator for Nonaqueous Electrolyte Battery The positive electrode was made of lithium nickelate powder and carbonaceous conductive material powder.
And a paste (N-methylpyrrolidone solvent) obtained by mixing polyvinylidene fluoride at a weight ratio of 87: 10: 3 with 2
It was applied to a 0-μm aluminum foil, dried and pressed to produce a 85-μm-thick sheet. For the negative electrode, a paste (N-methylpyrrolidone solvent) in which graphite powder and polyvinylidene fluoride were mixed at a weight ratio of 90:10 was applied to a 10-μm copper foil, dried and pressed to prepare a 100-μm-thick sheet. As the electrolytic solution, a solution prepared by dissolving lithium hexafluorophosphate (1 mol / L concentration) in a mixed solvent of ethylene carbonate, dimethyl carbonate, and ethyl methyl carbonate (weight ratio: 30:35:35) was used. As the separator, a separator for a non-aqueous electrolyte battery described in Examples of the present invention was used.

The battery had a flat-plate structure with a positive electrode area of 2.34 cm ^2. The above-prepared batteries were stacked in the argon atmosphere box in the order of a negative electrode sheet, a separator, and a positive electrode sheet. Was impregnated. The flat battery thus produced was subjected to eight cycles at a charge voltage of 4.2 V and a discharge voltage of 2.75 V, and the discharge capacity at the eighth cycle (discharge current: 1.5 mA) was measured. In addition, the cycle deterioration was measured. When the battery was charged under the above conditions and the discharge capacity (discharge current: 22.5 mA) was measured, this was taken as the discharge capacity at 3C. 3C
The load characteristics of the battery at were obtained by the following equation. Battery load characteristics at 3C (%) = discharge capacity at 3C /
Discharge capacity at 0.2C x 100

(9) Safety Test on Cylindrical Battery A positive electrode sheet electrode and a negative electrode sheet electrode produced by the same method as in (8) are laminated in the order of a negative electrode, a separator, a positive electrode, and a separator via the above separator. The laminate was wound from one end to form a spiral electrode element. The above-mentioned electrode element was inserted into a battery can, impregnated with the above-mentioned non-aqueous electrolyte solution, and caulked via a gasket with a battery cover having a safety valve and serving as a positive electrode terminal, to obtain a cylindrical battery of 18650 size.

(10) Method of Measuring Average Particle Size of Ceramic Powder The average particle size is determined by analyzing a photograph obtained by an electron microscope using a particle size measuring instrument TGZ3 manufactured by Zeiss.

Embodiment 1 1. Production of poly (paraphenyleneterephthalamide) Poly (paraphenyleneterephthalamide) (hereinafter referred to as PPTA) was prepared using a 3-liter separable flask having a stirring blade, a thermometer, a nitrogen inlet tube and a powder addition port.
May be abbreviated. ) Was manufactured. The flask was sufficiently dried, 2200 g of N-methyl-2-pyrrolidone was charged, 151.07 g of calcium chloride powder vacuum-dried at 200 ° C. for 2 hours was added, and the mixture was heated to 100 ° C. and completely dissolved. After returning to room temperature, paraphenylenediamine, 6
8.23 g was added and completely dissolved. Add this solution to 20
Terephthalic acid dichloride, 1
24.97 g was added in 10 portions and added about every 5 minutes. However, one of the 10 divided terephthalic acid dichlorides is
The final addition was made after dissolving in NMP of the same weight as terephthalic acid dichloride. Then, with stirring, add the solution to 2
Aging was performed for 1 hour while maintaining the temperature at 0 ° C. ± 2 ° C. The mixture was filtered through a 1500 mesh stainless steel wire mesh. The resulting solution is P
The liquid crystal phase having a PTA concentration of 6% exhibited optical anisotropy. P
The intrinsic viscosity of PPTA obtained by sampling a part of the PTA solution and reprecipitating with water was 2.01 dl / g.

2. Preparation of PPTA slurry solution for coating 65 g of PPTA solution of
500 with thermometer, nitrogen inlet and liquid addition port
weighing 235 g of NMP
Was finally added to prepare an isotropic phase solution having a PPTA concentration of 1.3% by weight, followed by stirring for 60 minutes. 3.9 g of alumina fine particles (Nippon Aerosil Co., Ltd., alumina C, average particle diameter 0.013 μm) were mixed with the above solution,
Stir for 40 minutes. The slurry solution in which the alumina fine particles were sufficiently dispersed was filtered through a 1000-mesh wire net, and then defoamed under reduced pressure to obtain a coating slurry solution.

3. Preparation of coating film Thickness of 10 on a drum of 550 mm in diameter and 350 mm in length
A 0 μm PET film was wound. On a PET film, a substrate (polyester paper, trade name: 0132TH-8 fine denier type, basis weight 8 g / m ² , thickness 20 μm;
Japan Vilene Co., Ltd. product). One side of the substrate was fixed to the drum with tape. A 0.6 kg weight was hung on the other side so that a load was evenly applied to the substrate. A stainless steel coating bar having a diameter of 20 mm was arranged at the top of the drum in parallel so that the clearance from the drum was 0.3 mm. The drum was rotated and stopped so that the end of the side fixed with the tape of the base material was between the drum and the coating bar. While supplying the PPTA slurry solution for coating prepared above onto the base material before the coating bar, the drum was rotated at 0.5 rpm to coat the base material.

After the entire substrate was coated, the rotation of the drum was stopped, and the substrate was kept at 23 ° C. in an atmosphere of 50% humidity for 10 minutes to precipitate PPTA. The 100 μm PET film and the coating film formed by coating and depositing the slurry solution on the substrate were removed from the drum while being integrated, immersed in ion exchange water, and washed for 12 hours while flowing ion exchange water. After washing, remove the PET film, sandwich the wet coated film between polyester fabrics from both sides, further sandwich with aramid felt, place on a 3 mm thick aluminum plate, and place a 0.1 mm thick nylon film on top of it. And seal it around with a sealing material.
It was dried at 50 ° C. for 2 hours to obtain a dry coated film and the like.

[0086] 4. Coating of a polyolefin suspension Polyolefin (hereinafter sometimes abbreviated as “PO”)
(Chemipearl WF640 and Chemipearl WP100 (manufactured by Mitsui Petrochemical Co., Ltd.)) were mixed in equal amounts, and ion-exchanged water was added to a solid content of 30% to prepare a polyolefin suspension for coating. Chemipearl WF640 and Chemipearl WP100: low molecular weight polyolefin having a particle size of 1 μm (measured by Coulter counter method)

A 25 μm-thick PET film subjected to a release treatment was wound on a drum having a diameter of 550 mm and a length of 350 mm. On the PET film, width 300 mm, length 90
The dried coating film cut to 0 mm was wound, and one side was fixed to a drum with a tape. On the other side, a 0.6 kg weight was suspended so that a load was evenly applied to the dry coating film. A stainless steel coating bar having a diameter of 20 mm was arranged at the top of the drum in parallel so that the clearance from the drum was 0.075 mm. The drum was rotated and stopped so that the end of the side of the dry coating film fixed with the tape was between the drum and the coating bar. Adjusted above on the dry coating film just before the coating bar,
While supplying the polyolefin suspension for coating, the drum was rotated at 0.5 rpm to apply the polyolefin suspension onto the dry coating film. When the entire dry coating film or the like was coated, the rotation of the drum was stopped, and the coating was left for 60 minutes and dried to obtain a non-aqueous electrolyte separator.

5. Physical Properties of Nonaqueous Electrolyte Battery Separator The above nonaqueous electrolyte separator has a thickness of 26.3 μm.
m, basis weight 19.2g / m ² (PET sheet 8g / m ^2, PP
TA 3.1 g / m ² , alumina 3.1 g / m ² , PO 5.0
g / m ² ) and the porosity was 44.8%. Observation of the separator with a scanning electron microscope revealed that one side had a thickness of about 0.1 mm.
1 μm or less of fibril-shaped or layered PPTA resin, alumina fine particles having a particle size of about 0.013 μm are dispersed between the fibrils, and a pore diameter of 0.05 to 0.2 μm
Was a porous layer having pores. On the other side,
Polyolefin particles having a particle size of about 1 μm had a thickness of about 5 μm. When the cross section is observed, a fibril-like PPTA of about 0.1 μm or less is formed between the polyester fibers of the base paper.
Alumina fine particles having a particle size of about 0.013 μm were filled between the resins in a dispersed state. The air permeability of the separator is 105 cc / sec, and the tensile strength is 4.9 kg / m.
m ² , breaking strain 2.8%, tear strength 4.9kg
/ Mm, the tear propagation resistance was 2.5 kg / mm.

6. Measurement of Shutdown Performance and Evaluation of Heat Resistance The internal electrical resistance at 25 ° C. of the separator before heating was 25Ω. As the temperature of the sample increases, the internal electrical resistance gradually decreases,
From there, the internal electric resistance began to rise and rose to 100Ω at around 120 ° C. The temperature was further increased to 200 ° C., but there was no decrease in electric resistance due to the meltdown. From the above results, it was found that the present separator has a shutdown function and a heat resistance for interrupting the current when the temperature rises.

7. Evaluation as Separator for Nonaqueous Electrolyte Battery The discharge capacity at the eighth cycle of the obtained separator was 1
It was 88 mAH / g (discharge current: 1.5 mA) and operated normally without cycle deterioration. Load characteristics are 41 at 3C
%Met. From the above results, it was found that the present separator has performance as a separator for a non-aqueous electrolyte battery.

8. Safety Test on Cylindrical Batteries Two cylindrical batteries obtained by the above-described method were charged to 150% of the rated capacity to make them overcharged, and then a nail penetration test was performed. The method of the nail penetration test is based on the guideline for evaluating the safety of lithium secondary batteries of the Japan Storage Battery Association (Japan Storage Battery Association of Japan guideline SBA-G1101-199).
According to 5). The batteries subjected to the test did not explode nor ignite, despite the severe condition of overcharging.

Embodiment 2 1. Preparation of PPTA Slurry Solution for Coating A coating solution was prepared in the same manner as in Example 1 except that the weight of the alumina fine particles to be mixed was 39 g. 2. Preparation of coating film The clearance between the stainless steel coating bar and the drum is 0.
3 of Example 1 except that they are arranged in parallel so as to be 1 mm.
It was produced in the same manner as described above. 3. Coating of Polyolefin Suspension Layer A separator for a non-aqueous electrolyte battery was obtained in the same manner as in item 4 of Example 1.

4. Physical Properties of Nonaqueous Electrolyte Battery Separator The above nonaqueous electrolyte battery separator has a thickness of 24.
1 μm, basis weight 17.8 g / m^Two(PET paper 8g / m^Two,
PPTA 0.42 g / m^Two, Alumina 4.2g / m ^Two, PO
5.2g / m^Two), And the porosity was 45.3%. Scanning type
Observing the separator with a scanning microscope, one side was approximately
Fibrillar or layered PPTA resin of 0.1 μm or less
And a particle size of about 0.013 μm between the fibrils.
Alumina fine particles are dispersed, and the pore size is 0.05-0.2
The porous layer had pores of μm. The other side
Means that polyolefin particles having a particle size of about 1 μm
There was about. Observation of the cross section shows that the polyester paper
Fibril-like PP of about 0.1 μm or less
Fine alumina particles with a particle size of about 0.013 μm between TA resins
The child was packed in a dispersed state. Book separator
The air permeability was 750 cc / sec.

5. Measurement of Shutdown Performance and Evaluation of Heat Resistance The internal electrical resistance at 25 ° C. of the separator before heating was 20Ω. As you increase the temperature of the sample,
Although the internal electric resistance gradually decreases, the internal electric resistance starts to increase from around 100 ° C.
Rose to 2Ω. The temperature was further increased to 200 ° C., but there was no decrease in electric resistance due to the meltdown. From the above results, it was found that the present separator has a shutdown function and a heat resistance for interrupting the current when the temperature rises.

6. Evaluation as Separator for Nonaqueous Electrolyte Battery The discharge capacity at the eighth cycle of the obtained separator was 1
It was 93 mAH / g (discharge current: 1.5 mA), and it operated normally without cycle deterioration. The load characteristic is 47 at 3C.
%Met. From the above results, it was found that the present separator has performance as a separator for a non-aqueous electrolyte battery.

Embodiment 3 1. Preparation of Polyimide Resin Slurry Solution for Coating Polyimide Resin N Soluble in Solvent with 20% Polymer Concentration
MP solution (Ricacoat, PN-20; Shin Nippon Rika Co., Ltd.)
Product) 100 g and alumina fine particles (product of Nippon Aerosil Co .; alumina C, average particle diameter 0.013 μm) 2 g
Was weighed into a 500 ml separable flask having a stirring blade, a thermometer, a nitrogen inlet tube, and a liquid addition port.
Stirred for 0 minutes. NMP (45 ml) was added and the mixture was stirred for 120 minutes. The slurry solution in which the alumina fine particles were sufficiently dispersed was filtered through a 1000-mesh wire net, and then defoamed under reduced pressure to obtain a coating slurry solution. 2. Preparation of coating film The clearance between the stainless steel coating bar and the drum is 0.
It was prepared in the same manner as 3 in Example 1 except that it was arranged in parallel so as to be 1 mm. 3. Coating of polyolefin suspension A separator for a non-aqueous electrolyte battery was obtained in the same manner as in Example 1.

4. Physical Properties of Nonaqueous Electrolyte Battery Separator The above nonaqueous electrolyte battery separator has a thickness of 27.
4 μm, basis weight 18.1 g / m ² (PET paper 8 g / m ² ,
Polyimide 4.4 g / m ² , alumina 0.44 g / m ² , P
O 5.3 g / m ² ) and the porosity was 45.4%. When the cross section of the separator was observed with a scanning electron microscope, alumina particles having a particle size of about 0.013 μm were dispersed in the porous polyimide resin between the polyester fibers of the base paper to form open cells. The filled layer and polyolefin particles having a particle size of about 1 μm have a thickness of 5 μm.
m. The air permeability of this separator is 15
It was 0 cc / sec.

5. Measurement of Shutdown Performance and Evaluation of Heat Resistance The internal electrical resistance at 25 ° C. of the separator before heating was 35Ω. As the temperature of the sample increases, the internal electrical resistance gradually decreases,
From there, the internal electric resistance began to rise and rose to 70Ω at around 120 ° C. The temperature was further increased to 200 ° C., but there was no decrease in electric resistance due to the meltdown. From the above results, it was found that the present separator has a shutdown function and a heat resistance for interrupting the current when the temperature rises.

6. Evaluation as Separator for Nonaqueous Electrolyte Battery The discharge capacity at the eighth cycle of the obtained separator was 1
It was 83 mAH / g (discharge current: 1.5 mA) and operated normally without cycle deterioration. The load characteristic was 8% at 3C. From the above results, it was found that the present separator has performance as a separator for a non-aqueous electrolyte battery.

Embodiment 4 1. Preparation of Polyimide Resin Slurry Solution for Coating NMP Solution of Polyimide Resin with 20% Polymer Concentration (Licacoat, PN-20; Shin-Nippon Rika Co., Ltd.) 100
g and 7 g of alumina fine particles (product of Nippon Aerosil Co., Ltd .; alumina C, average particle size 0.013 μm),
500 with thermometer, nitrogen inlet and liquid addition port
The mixture was weighed into a ml separable flask and stirred for 120 minutes. 28 ml of NMP was added and stirred for 120 minutes. A slurry solution in which alumina fine particles are sufficiently dispersed is 1000
After filtration through a mesh wire mesh, the mixture was defoamed under reduced pressure to obtain a coating slurry solution. 2. Preparation of coating film The clearance between the stainless steel coating bar and the drum is 0.
3 of Example 1 except that they are arranged in parallel so as to be 1 mm.
Prepared in the same manner as 3. Coating of polyolefin suspension A separator for a non-aqueous electrolyte battery was obtained in the same manner as in item 4 of Example 1.

4. Physical Properties of Nonaqueous Electrolyte Battery Separator The above nonaqueous electrolyte battery separator has a thickness of 26.
7 μm, basis weight 17.7 g / m^Two(PET paper 8g / m^Two,
3.4 g / m of polyimide^Two, Alumina 1.2g / m ^Two, PO
5.1 g / m^Two), And the porosity was 46.5%. Scanning type
When the cross section of the separator was observed with a microscope,
Porous polyimide tree between polyester fibers of paper
Alumina fine particles with a particle size of about 0.013 μm
It is dispersed and becomes an open cell, and it is filled
The layer and polyolefin particles having a particle size of about 1 μm have a thickness of 5 μm.
It was about a layer. The air permeability of this separator is 680c
c / sec.

5. Measurement of Shutdown Performance The internal electrical resistance at 25 ° C. of the separator before heating was 25Ω. As the temperature of the sample is increased, the internal electric resistance gradually decreases, but the internal electric resistance starts to increase from around 100 ° C.
Rose to 9Ω. The temperature was further increased to 200 ° C., but there was no decrease in electric resistance due to the meltdown. From the above results, it was found that the present separator has a shutdown function and a heat resistance for interrupting the current when the temperature rises.

6. Evaluation as Separator for Nonaqueous Electrolyte Battery The discharge capacity at the eighth cycle of the obtained separator was 1
It was 90 mAH / g (discharge current: 1.5 mA) and operated normally without cycle deterioration. Load characteristics 24% at 3C
Met. From the above results, it was found that the present separator has performance as a separator for a non-aqueous electrolyte battery.

Embodiment 5 1. Preparation of Polyimide Resin Slurry Solution for Coating NMP Solution of Polyimide Resin with 20% Polymer Concentration (Licacoat, PN-20; Shin-Nippon Rika Co., Ltd.) 100
g and 10 g of alumina fine particles (product of Nippon Aerosil Co., Ltd .; alumina C, average particle size 0.013 μm) having a stirring blade, a thermometer, a nitrogen inlet tube and a liquid addition port.
It was weighed into a 00 ml separable flask and stirred for 120 minutes. NMP (40 ml) was added and the mixture was stirred for 120 minutes. A slurry solution in which alumina fine particles are sufficiently dispersed
After filtration through a 0-mesh wire net, defoaming was performed under reduced pressure to obtain a coating slurry solution. 2. Preparation of coating film The clearance between the stainless steel coating bar and the drum is 0.
It was prepared in the same manner as 3 in Example 1 except that it was arranged in parallel so as to be 1 mm. 3. Polyolefin suspension coating Stainless steel coating bar with 0 mm clearance from drum.
A separator for a non-aqueous electrolyte battery was obtained in the same manner as in item 4 of Example 1, except that the separator was arranged in parallel so as to be 05 mm.

4. Physical Properties of Nonaqueous Electrolyte Battery Separator The above nonaqueous electrolyte battery separator has a thickness of 29.
6 μm, weight 20.5 g / m^Two(PET paper 8g / m^Two,
4.9 g / m of polyimide^Two, Alumina 2.5g / m ^Two, PO
5.1 g / m^Two), And the porosity was 48.1%. Scanning type
When the cross section of the separator was observed with a microscope,
Porous polyimide tree between polyester fibers of paper
Alumina fine particles with a particle size of about 0.013 μm
It is dispersed and becomes an open cell, and it is filled
The layer and polyolefin particles having a particle size of about 1 μm have a thickness of 5 μm.
It was about a layer.

The air permeability of the separator is 3200 cc /
sec, tensile strength 4.5 kg / mm ² , breaking strain 1
4.0%, the tear strength was 7.5 kg / mm, and the tear propagation resistance was 3.3 kg / mm.

5. Measurement of Shutdown Performance and Evaluation of Heat Resistance The internal electrical resistance at 25 ° C. of the separator before heating was 35Ω. As you increase the temperature of the sample,
Although the internal electric resistance gradually decreases, the internal electric resistance starts increasing from around 100 ° C. and reaches 221 around 120 ° C.
Rose to Ω. The temperature was further increased to 200 ° C., but there was no decrease in electric resistance due to the meltdown. From the above results, it was found that the present separator has a shutdown function and a heat resistance for interrupting the current when the temperature rises.

6. Evaluation as Separator for Nonaqueous Electrolyte Battery The discharge capacity at the eighth cycle of the obtained separator was 1
It was 87 mAH / g (discharge current: 1.5 mA), and it operated normally without cycle deterioration. 63% load characteristics at 3C
Met. From the above results, it was found that the present separator has performance as a separator for a non-aqueous electrolyte battery.

7. Safety Test with Cylindrical Battery Two cylindrical batteries obtained by the above-described method were charged to 150% of the rated capacity to make them overcharged, and then a nail penetration test was performed. The method of the nail penetration test is based on the guideline of safety evaluation standard for lithium secondary batteries by the Japan Storage Battery Association (Japan Storage Battery Association of Japan guideline SBA-G1101-199).
According to 5). The batteries subjected to the test did not explode nor ignite, despite the severe condition of overcharging.

Embodiment 6 1. Preparation of Polyimide Resin Slurry Solution for Coating NMP Solution of Polyimide Resin with 20% Polymer Concentration (Licacoat, PN-20; Shin-Nippon Rika Co., Ltd.) 100
g and fine alumina particles having an average particle diameter of 0.4 μm (AMS-1
2; Sumitomo Chemical Co., Ltd. product) 10 g, 500 ml having a stirring blade, a thermometer, a nitrogen inlet tube and a liquid addition port
Was weighed into a separable flask and stirred for 120 minutes.
After adding 45 ml of NMP and stirring for 120 minutes, the mixture was defoamed under reduced pressure to obtain a coating slurry solution. When this slurry solution was allowed to stand for 24 hours, some of the alumina fine particles had settled. 2. Preparation of coating film The clearance between the stainless steel coating bar and the drum is 0.
3 of Example 1 except that they are arranged in parallel so as to be 1 mm.
Prepared in the same manner as 3. Coating of polyolefin suspension A separator for a non-aqueous electrolyte battery was obtained in the same manner as in item 4 of Example 1.

[0111] 4. Physical Properties of Nonaqueous Electrolyte Battery Separator The above nonaqueous electrolyte battery separator has a thickness of 26.
5 μm, basis weight 17.8 g / m ² (PET paper 8 g / m ² ,
3.0 g / m ² , alumina 1.5 g / m ² , PO 5.3 g / m ²
m ² ), and the porosity was 46.0%. When the cross section of the separator was observed with a scanning electron microscope, alumina fine particles having an average particle size of about 0.4 μm were dispersed in the porous polyimide resin between the polyester fibers of the base paper,
It was an open cell, in which the filled layer and the polyolefin particles having a particle size of about 1 μm were a layer having a thickness of about 5 μm. The air permeability of this separator is 120 cc / sec.
There was unevenness in the location from c to 270 cc / sec.

Comparative Example 1 1. Preparation of Polyimide Resin Solution for Coating Polyimide resin of NMP solution with 20% polymer concentration (Licacoat, PN-20; product of Shin Nippon Rika Co., Ltd.) 100
g was weighed into a 500 ml separable flask having a stirring blade, a thermometer, a nitrogen inlet tube and a liquid addition port, and degassed under reduced pressure to obtain a coating solution. 2. Preparation of coating film The clearance between the stainless steel coating bar and the drum is 0.
Example 1 except that they were arranged in parallel so as to be 05 mm.
Prepared in the same manner as 3. 3. Coating of polyolefin suspension A separator for a non-aqueous electrolyte battery was obtained in the same manner as in item 4 of Example 1.

4. Physical Properties of Nonaqueous Electrolyte Battery Separator The above nonaqueous electrolyte battery separator has a thickness of 28.
0 .mu.m, basis weight 17.7g / m ² (PET sheet 8 g / m ^2,
Polyimide ^{4.6g / m 2, PO5.1g / m} 2), it was void ratio 47.3%. Observation of the cross section of the separator for non-aqueous electrolyte batteries with a scanning electron microscope, between the polyester fibers of the base paper, a porous polyimide resin,
The filled layer and the polyolefin particles having a particle size of about 1 μm were layers having a thickness of about 5 μm. The air permeability of this separator was as low as 3 cc / sec. 5. Measurement of shutdown performance, evaluation as separator for battery Measurement was impossible due to impregnation failure of electrolyte solution.

Embodiment 7 1. Preparation of PPTA dope for coating PPTA dope for coating 100 g of the PPTA dope of Example 1 having a stirring blade, a thermometer, a nitrogen inlet tube, and a liquid addition port.
Weighed into a 00 ml separable flask, 140 g of N
MP was added, and finally the PPTA concentration was 2.5% by weight.
And stirred for 60 minutes. P above
A PTA concentration of 2.5% by weight was mixed with 6 g of alumina fine particles (Alumina C, manufactured by Nippon Aerosil Co., Ltd.), and 24
Stirred for 0 minutes. The mixture was passed through a Nanomizer three times, and the coated dope in which alumina fine particles were sufficiently dispersed was filtered through a 1000-mesh wire net. Thereafter, defoaming was performed under reduced pressure to obtain a coating dope.

[0115] 2. Preparation of Porous Film Layer Thickness 10 on a 550 mm diameter, 350 mm long drum
A 0 μm PET film was wound. Substrate (polyethylene separator, basis weight 10.5) on PET film
g / m ² , thickness 16 μm, porosity 40%). One side of the substrate was fixed to the drum with tape. 0 in the other.
A 6 kg weight was suspended so that a load was evenly applied to the substrate. A stainless steel coating bar having a diameter of 25 mm was arranged at the top of the drum so as to have a clearance of 0.15 mm from the drum. The drum was rotated and stopped so that the end of the side fixed with the tape of the base material was between the drum and the coating bar. Adjusted above on the substrate before the coating bar,
While supplying the coating dope, the drum was rotated at 0.5 rpm to coat the substrate. Apply the entire base material and further rotate the drum while keeping the temperature at 23 ° C and 50% humidity.
For 10 minutes to precipitate PPTA. 10
The PET film having a thickness of 0 μm and the film obtained by coating and depositing the dope on the substrate were removed from the drum while being integrated, and immersed in ion-exchanged water.
Washed for hours. After washing, take the PET film, sandwich the wet film between the polyester cloth from both sides, further sandwich with felt made of aramid, put on a 3 mm thick aluminum flat plate, put a 0.1 mm thick nylon film from above, The periphery was sealed with a sealing material, and dried at 70 ° C. for 6 hours while evacuating the inside to obtain a separator for a non-aqueous electrolyte battery.

3. Physical Properties of Nonaqueous Electrolyte Battery Separator The above nonaqueous electrolyte battery separator has a thickness of 24.
0 .mu.m, basis weight 17.0 g / m ² (polyethylene separator ^{10.5g / m 2, PPTA3.2g / m} 2, alumina 3.2g / m ^2), was void ratio 59.4% of the heat-resistant layer. Observation of the film with a scanning electron microscope revealed that one side was fibril-like or layer-like PPTA of about 0.1 μm or less.
Resin, 0.013μm particle size between the fibrils
About alumina fine particles are dispersed, and the pore size is 0.05 to
The porous layer had pores of 0.2 μm. Observation of the cross section shows that PPTA
It had a two-layer structure with the resin penetrating and bonding. The air permeability of this film was 43 cc / sec.

4. Measurement of shutdown performance The internal electrical resistance at 25 ° C. of the film before heating was 20Ω. As the temperature of the sample increases, the internal electrical resistance gradually decreases.
The internal electrical resistance began to rise and rose to 2 KΩ at around 135 ° C. The temperature was further increased to 200 ° C., but there was no decrease in electric resistance due to the meltdown. From the above results, it was found that the present separator has a shutdown function and a heat resistance for interrupting the current when the temperature rises.

[0118] 5. Evaluation as Separator for Nonaqueous Electrolyte Battery The discharge capacity at the eighth cycle of the obtained film was 193.
It was mAH / g (discharge current: 1.5 mA) and operated normally without cycle deterioration. The load characteristic was 53% at 3C. From the above results, it was found that the present separator has performance as a separator for a non-aqueous electrolyte battery.

Embodiment 8 1. Preparation of Polyimide Resin Dope for Coating Polyimide resin (P
N20, a product of Shin Nihon Rika Co., Ltd.) 100 g and alumina fine particles (alumina C, a product of Nippon Aerosil Co., Ltd.)
g was weighed into a 500 ml separable flask having a stirring blade, a thermometer, a nitrogen inlet tube, and a liquid addition port.
Stirred for 20 minutes. NMP (60 ml) was added and the mixture was stirred for 120 minutes. The mixture was passed through a Nanomizer three times to sufficiently disperse the alumina fine particles, and the coated dope was filtered through a 1000-mesh wire net. Thereafter, defoaming was performed under reduced pressure to obtain a coating dope.

[0120] 2. Preparation of Porous Film Layer Thickness 10 on a 550 mm diameter, 350 mm long drum
A 0 μm PET film was wound. 10. Substrate (polyethylene separator, basis weight) on PET film
5 g / m ² , thickness 16 μm, porosity 40%).
One side of the substrate was fixed to the drum with tape. A 0.6 kg weight was hung on the other side so that a load was evenly applied to the substrate. A stainless steel coating bar having a diameter of 25 mm was arranged at the top of the drum in parallel so that the clearance from the drum was 0.03 mm. The drum was rotated and stopped so that the end of the side fixed with the tape of the base material was between the drum and the coating bar. While supplying the coating dope prepared above on the base material before the coating bar, the drum was rotated at 0.5 rpm.
And applied to the substrate.

The whole substrate was coated, and while rotating the drum, it was kept in an atmosphere of 23 ° C. and 50% humidity for 10 minutes.
After a few minutes, PPTA was precipitated. 100 μm PET
The film in which the dope was coated and deposited on the film and the substrate was removed from the drum while being integrated, immersed in ion-exchanged water, and washed for 12 hours while flowing ion-exchanged water.
After washing, take the PET film, sandwich the wet film between the polyester cloth from both sides, further sandwich with felt made of aramid, put on a 3 mm thick aluminum flat plate, put a 0.1 mm thick nylon film from above, The periphery was sealed with a sealing material, and dried at 70 ° C. for 6 hours while evacuating the inside to obtain a separator for a non-aqueous electrolyte battery.

3. Physical Properties of Separator for Nonaqueous Electrolyte Battery The above dried film has a thickness of 28.0 μm and a basis weight.
17.5 g / m ² (polyethylene separator 10.5
^{g / m 2, PI4.7g / m} 2, alumina 2.3 g / m ²⁾
The porosity of the heat-resistant layer was 65.9%). Observation of the cross section of the film with a scanning electron microscope revealed that alumina microparticles were dispersed in porous polyimide resin, and those that had become open cells entered the polyethylene separator of the base material and were bonded together in two layers. Had a structure. The air permeability of this film was 60 cc / sec.

4. Measurement of Shutdown Performance The internal electrical resistance at 25 ° C. of the film before heating was 35Ω. As you increase the temperature of the sample,
Although the internal electric resistance gradually decreases, the internal electric resistance starts to increase from around 130 ° C.
Rose to KΩ. The temperature was further increased to 200 ° C., but there was no decrease in electric resistance due to the meltdown. From the above results, it was found that the present separator has a shutdown function and a heat resistance for interrupting the current when the temperature rises.

[0124] 5. Evaluation as Separator for Nonaqueous Electrolyte Battery The discharge capacity at the eighth cycle of the obtained film was 183
It was mAH / g (discharge current: 1.5 mA) and operated normally without cycle deterioration. The load characteristic was 61% at 3C. From the above results, it was found that the present separator has performance as a separator for a non-aqueous electrolyte battery.

Embodiment 9 1. Preparation of Polyimide Resin Dope for Coating Polyimide resin (P
N20, 50 g of Shin Nippon Rika Co., Ltd.) and 150 g of alumina fine particles (Sumitomo Chemical Co., Ltd. product, Sumicorundum, average particle size 0.3 μm, particle size distribution 0.1 to 1.0 μm)
Is weighed into a 500 ml separable flask having a stirring blade, a thermometer, a nitrogen inlet tube and a liquid addition port, and NM
P350ml was added and stirred for 120 minutes. The mixture was passed through a nanomizer three times to sufficiently disperse the alumina fine particles, and the coating dope was defoamed under reduced pressure to obtain a coating dope.

2. Preparation of Porous Film Layer Thickness 10 on a 550 mm diameter, 350 mm long drum
A 0 μm PET film was wound. Substrate (polyethylene separator, basis weight 10.5) on PET film
g / m ² , thickness 16 μm, porosity 40%). One side of the substrate was fixed to the drum with tape. 0 in the other.
A 6 kg weight was suspended so that a load was evenly applied to the substrate. A stainless steel coating bar having a diameter of 25 mm was arranged at the top of the drum so as to have a clearance of 0.05 mm from the drum. The drum was rotated and stopped so that the end of the side fixed with the tape of the base material was between the drum and the coating bar. Adjusted above on the substrate before the coating bar,
While supplying the coating dope, the drum was rotated at 0.5 rpm to coat the substrate. After coating the entire base material, the solvent was evaporated by heating at 70 ° C. for 2 hours while further rotating the drum to obtain a separator for a non-aqueous electrolyte battery.

[0127] 3. Physical Properties of Separator for Nonaqueous Electrolyte Battery The above dried film has a thickness of 24.0 μm and a basis weight.
28.1 g / m ² (polyethylene separator 10.5
^{g / m 2, PI1.1g / m} 2, alumina 16.5g /
m ² ), and the porosity of the heat-resistant layer was 25.7%. Observation of the cross section of the film with a scanning electron microscope revealed that alumina microparticles were dispersed in porous polyimide resin, and those that had become open cells entered the polyethylene separator of the base material and were bonded together in two layers. Had a structure.
The air permeability of the film was 38 cc / sec.

4. Measurement of Shutdown Performance The internal electrical resistance at 25 ° C. of the film before heating was 31Ω. As you increase the temperature of the sample,
Although the internal electric resistance gradually decreases, the internal electric resistance starts increasing from about 130 ° C. and becomes 2.8 at about 135 ° C.
Rose to KΩ. The temperature was further increased to 200 ° C., but there was no decrease in electric resistance due to the meltdown. From the above results, it was found that the present separator has a shutdown function and a heat resistance for interrupting the current when the temperature rises.

5. Evaluation as Separator for Nonaqueous Electrolyte Battery The discharge capacity at the eighth cycle of the obtained film was 183
It was mAH / g (discharge current: 1.5 mA) and operated normally without cycle deterioration. The load characteristics were 40% at 3C. From the above results, it was found that the present separator has performance as a separator for a non-aqueous electrolyte battery.

[0130]

The separator for a non-aqueous electrolyte battery of the present invention makes use of the characteristics of a heat-resistant nitrogen-containing aromatic polymer having high heat resistance and a high short-circuit temperature, and has good ion permeability and good battery characteristics. . Further, the separator for a non-aqueous electrolyte battery of the present invention has the safety of shutting down when overheated, does not melt even when heated, and has a high short-circuit temperature, so that it is more excellent in safety. Furthermore, the lithium secondary battery of the present invention has a high short-circuit temperature and is more excellent in safety by using the separator.

Claims (17)

[Claims] 1. A non-aqueous electrolyte battery separator comprising a heat-resistant nitrogen-containing aromatic polymer and ceramic powder. 2. A non-aqueous electrolyte battery separator comprising a substrate made of woven fabric, non-woven fabric, paper or porous film, a heat-resistant nitrogen-containing aromatic polymer and ceramic powder. 3. The method according to claim 1, wherein the weight of the substrate is 40 g / unit area.
m ² or less, and a non-aqueous electrolyte battery separator of claim 2 in which the thickness is equal to or is less base material 70 [mu] m. 4. The non-aqueous electrolyte battery separator according to claim 2, wherein the substrate is a substrate containing organic fibers and / or inorganic fibers. 5. The non-aqueous electrolyte battery separator according to claim 4, wherein the organic fibers are made of a thermoplastic polymer. 6. The non-aqueous electrolyte battery separator according to claim 4, wherein the inorganic fibers are glass fibers. 7. A non-aqueous electrolyte battery separator having a temperature of 260 ° C.
A thermoplastic polymer which melts below is contained in an amount of 10% by weight or more based on the whole of the separator, and the thermoplastic polymer is a polymer which melts when a temperature rises and closes a gap of the separator. 7. The non-aqueous electrolyte battery separator according to any one of 6. 8. A non-aqueous electrolyte battery separator comprising a coating film produced by a method comprising the following steps (a) to (e). (A) In a polar organic solvent solution containing a heat-resistant nitrogen-containing aromatic polymer, 1 to 1500 parts by weight of a ceramic powder is dispersed with respect to 100 parts by weight of the heat-resistant nitrogen-containing aromatic polymer.
Prepare a slurry solution that may contain a thermoplastic resin that melts at or below 0 ° C. (B) applying the slurry solution to form a coating film. (C) depositing the heat-resistant nitrogen-containing aromatic polymer on the coating film. (D) removing the polar organic solvent from the coating film; (E) drying the coated film; 9. A non-aqueous electrolyte battery separator comprising a coating film produced by a method comprising the following steps (a) to (e). (A) In a polar organic solvent solution containing a heat-resistant nitrogen-containing aromatic polymer, 1 to 1500 parts by weight of a ceramic powder is dispersed with respect to 100 parts by weight of the heat-resistant nitrogen-containing aromatic polymer.
Prepare a slurry solution that may contain a thermoplastic resin that melts at or below 0 ° C. (B) The slurry solution is applied to a substrate made of woven fabric, nonwoven fabric, paper or a porous film to form a coated film. (C) depositing the heat-resistant nitrogen-containing aromatic polymer on the coating film. (D) removing the polar organic solvent from the coating film; (E) drying the coated film; 10. The non-aqueous electrolyte battery separator according to claim 8 or 9, further comprising a fine particle suspension of a thermoplastic polymer, followed by drying and a fine particle layer of a thermoplastic resin. Non-aqueous electrolyte battery separator. 11. The non-aqueous electrolyte battery separator according to claim 1, wherein the heat-resistant nitrogen-containing aromatic polymer is an aromatic polyimide or an aromatic polyamide. 12. An aromatic polyamide having an intrinsic viscosity of 1.0 to 1.0.
The non-aqueous electrolyte battery separator according to claim 11, which is a para-oriented aromatic polyamide of 2.8 dl / g. 13. The non-aqueous electrolyte battery separator according to claim 11, wherein the aromatic polyimide is a solvent-soluble aromatic polyimide. 14. The ceramic powder, wherein primary particles have an average particle size of 1.0 μm or less, and the content of the ceramic powder is 1% by weight to 95% by weight of the total weight of the separator.
The nonaqueous electrolyte battery separator according to any one of claims 1 to 13, wherein the separator is a ceramic powder as described below. 15. The non-aqueous electrolyte battery separator according to claim 1, wherein the ceramic powder is at least one ceramic powder selected from the group consisting of metal oxides, metal nitrides, and metal carbides. 16. The non-aqueous electrolyte battery separator according to claim 15, wherein the metal oxide is alumina, silica, titanium dioxide or zirconium oxide. 17. A lithium secondary battery comprising the non-aqueous electrolyte battery separator according to claim 1.