JP2013020769A - Separator for nonaqueous electrolyte battery and nonaqueous electrolyte battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a separator for a nonaqueous electrolyte battery, excellent in adhesiveness with an electrode, heat resistance and shutdown characteristics; and a nonaqueous electrolyte battery excellent in cycle characteristics.SOLUTION: The separator for a nonaqueous electrolyte battery includes: a porous base material containing polyolefin; a heat resistant porous layer provided on both sides of the porous base material and containing a heat resistant resin; and an adhesive porous layer provided on at least one side of the heat resistant porous layer and containing a fluoro-based resin.

Description

  The present invention relates to a separator for a nonaqueous electrolyte battery and a nonaqueous electrolyte battery.

Nonaqueous electrolyte batteries typified by lithium ion secondary batteries are widely used as main power sources for portable electronic devices such as mobile phones and notebook computers.
In recent years, for the purpose of reducing the weight of a nonaqueous electrolyte battery, an aluminum exterior material has been developed as an exterior material instead of a metal can. When an aluminum exterior material is used, the electrode is liable to be displaced due to an external impact, or the electrolyte is liable to wither due to expansion / contraction of the electrode. Therefore, a separator excellent in electrode adhesion and electrolyte swellability is desired. Therefore, a separator in which a polyolefin microporous membrane is coated with a polyvinylidene fluoride-based resin (hereinafter abbreviated as PVdF), or a separator in which a mixture of an aramid resin and PVdF with heat resistance is coated is reported (for example, , See Patent Document 1). In addition, the following separators have been reported for the purpose of improving battery characteristics.

(1) A separator in which an aramid resin is laminated on a microporous polyolefin membrane is said to be excellent in suppression of thermal shrinkage and shutdown characteristics (see, for example, Patent Document 2).
(2) A separator in which PVdF is laminated on a microporous polyolefin membrane is excellent in cycle characteristics and temperature storage characteristics because it has good oxidation resistance and can prevent micro shorts at high temperatures (for example, Patent Document 3). reference).
(3) A separator in which PVdF is laminated on a polyolefin microporous film and further an aramid resin layer is laminated is suppressed in oxidative decomposition and is excellent in thermal shrinkage (see, for example, Patent Document 4).
(4) A separator in which an aramid resin is laminated on the positive electrode side of a polyolefin microporous membrane and PVdF is laminated on the negative electrode side is said to be excellent in oxidation resistance and gas generation suppression (see, for example, Patent Document 5).

Japanese Patent No. 3942277 Japanese Patent No. 4303307 JP 2006-286531 A JP 2009-187702 A Japanese Patent No. 3419393

As described above, various non-aqueous electrolyte battery separators have been reported. However, the mechanical strength, heat resistance, electrolyte retention, adhesion to the electrode, etc. have their merits and demerits. Has not been reported.
In view of the above circumstances, an object of the present invention is to provide a separator for a nonaqueous electrolyte battery excellent in adhesion to an electrode, heat resistance and shutdown characteristics, and a nonaqueous electrolyte battery excellent in cycle characteristics.

The present inventor has developed a separator in which a heat-resistant porous layer and an adhesive porous layer containing a fluororesin are laminated on a porous substrate containing polyolefin, and has adhesion to electrodes, heat resistance, and shutdown characteristics. It was found that all of these exhibited well-balanced performance, and that the cycle characteristics were improved when a battery was produced.
In order to solve the above problems, the present invention adopts the following configuration.

<1> Provided on at least one of a porous substrate containing polyolefin, a heat-resistant porous layer containing a heat-resistant resin, and a heat-resistant porous layer provided on both surfaces of the porous substrate; A separator for a nonaqueous electrolyte battery comprising: an adhesive porous layer containing a fluorine-based resin.
<2> The nonaqueous electrolyte battery separator according to <1>, wherein the adhesive porous layer has a coating amount in a range of 0.5 g / m ^{2 to} 3.5 g / m ² .
<3> The separator for a nonaqueous electrolyte battery according to <1> or <2>, wherein the heat-resistant porous layer contains at least one of an organic filler and an inorganic filler.
<4> The heat-resistant porous layer includes an inorganic filler, and the content of the inorganic filler is in the range of 1 to 10 parts by mass with respect to 1 part by mass of the heat-resistant resin. > The separator for nonaqueous electrolyte batteries according to any one of the above.
<5> The fluororesin is selected from the group consisting of (i) polyvinylidene fluoride, and (ii) vinylidene fluoride, perfluoroalkyl vinyl ether, hexafluoropropylene, trifluorochloroethylene, tetrafluoroethylene, and ethylene. The at least one monomer selected is at least one of a copolymer copolymerized at a molar fraction of the monomer of 1 to 10%, according to any one of <1> to <4>. Nonaqueous electrolyte battery separator.
<6> The heat resistant resin according to any one of <1> to <5>, wherein the heat resistant resin is at least one selected from the group consisting of wholly aromatic polyamide, polyamideimide, polyimide, polyetherimide, and polysulfone. The separator for nonaqueous electrolyte batteries as described.
<7> Any one of <1> to <6>, wherein the adhesive porous layer is provided on each of the heat-resistant porous layers provided on both surfaces of the porous substrate. A separator for a nonaqueous electrolyte battery according to Item.
<8> A positive electrode, a negative electrode, and the separator for a nonaqueous electrolyte battery according to any one of <1> to <7> disposed between the positive electrode and the negative electrode. A non-aqueous electrolyte battery that obtains an electromotive force by dedoping.

  ADVANTAGE OF THE INVENTION According to this invention, the nonaqueous electrolyte battery separator excellent in the adhesiveness with an electrode, heat resistance, and a shutdown characteristic, and the nonaqueous electrolyte battery excellent in cycling characteristics can be provided.

Hereinafter, embodiments of the present invention will be sequentially described. In addition, these description and Examples illustrate this invention, and do not restrict | limit the scope of the present invention.
In the present specification, a numerical range indicated using “to” indicates a range including the numerical values described before and after “to” as the minimum value and the maximum value, respectively.
In this specification, when expressing the stacking relationship of each layer as “upper” and “lower”, the layer closer to the substrate is referred to as “lower”, and the layer farther from the substrate is referred to as “upper” .

<Separator for non-aqueous electrolyte battery>
The separator for a non-aqueous electrolyte battery of the present invention is
A porous substrate containing polyolefin (hereinafter also referred to as “polyolefin porous substrate”, “porous substrate”, and “substrate”);
A heat resistant porous layer comprising a heat resistant resin provided on both surfaces of the porous substrate; and
An adhesive porous layer containing a fluorine-based resin provided on at least one of the heat-resistant porous layers.
The separator for a non-aqueous electrolyte battery is provided with a heat-resistant porous layer on both sides with a base material interposed therebetween, and an adhesive porous layer is provided on the layer, thereby providing adhesion to an electrode, heat resistance, and shutdown characteristics. Excellent performance in a well-balanced manner. The separator for a non-aqueous electrolyte battery is excellent in cycle characteristics because the adhesion between the electrode and the separator is maintained when the battery is manufactured, and the porous layer holds the electrolyte well.

[Polyolefin porous substrate]
The polyolefin porous substrate is a substrate having pores or voids therein. Examples of such a polyolefin substrate include a porous sheet such as a microporous membrane made of polyolefin and a fibrous material made of polyolefin. A microporous membrane is a membrane that has a large number of micropores inside and a structure in which these micropores are connected, and allows gas or liquid to pass from one surface to the other. It is.
The polyolefin porous substrate is a porous substrate that softens at 130 to 150 ° C., closes porous pores or voids, exhibits a shutdown function, and does not dissolve in the electrolyte of the nonaqueous electrolyte battery. Is preferred. In the present invention, a polyolefin microporous membrane is preferred as the porous substrate.

As the polyolefin microporous membrane, those having sufficient mechanical properties and ion permeability can be suitably used from among polyolefin microporous membranes applied to conventional non-aqueous electrolyte battery separators.
The polyolefin microporous membrane is preferably composed mainly of polyethylene from the viewpoint of having a shutdown function for ensuring the safety of the battery. Specifically, it is preferable to have a layer having a thickness of 5 μm or more containing 95% by mass or more of polyethylene.
In addition, from the viewpoint of ensuring battery safety when exposed to high temperatures, a polyolefin microporous membrane containing polypropylene in addition to polyethylene is preferred. In this case, considering the balance with the shutdown function, it is preferable to include 95% by mass or more of polyethylene and 5% by mass or less of polypropylene. In addition, the polyolefin microporous membrane includes at least two layers, at least one layer is made of polyethylene, and at least one layer is made of polypropylene, and the polyolefin microporous membrane is also preferable from the viewpoint of both shutdown function and heat resistance. Used.

  The polyolefin contained in the polyolefin microporous membrane preferably has a weight average molecular weight of 100,000 to 5,000,000. When the weight average molecular weight is 100,000 or more, sufficient mechanical properties can be secured. On the other hand, when the weight average molecular weight is 5 million or less, the shutdown characteristics are good and the film can be easily formed.

  The polyolefin microporous membrane can be produced, for example, by the following method. That is, it is a method in which a molten polyolefin resin is extruded from a T-die, formed into a sheet, subjected to crystallization treatment, stretched, and further heat treated to form a microporous film. Alternatively, by extruding a polyolefin resin melted with a plasticizer such as liquid paraffin from a T-die, cooling it into a sheet, stretching, and then extracting the plasticizer and heat treating it into a microporous membrane. is there.

The thickness of the polyolefin porous substrate is preferably 5 μm to 25 μm. When the film thickness is 5 μm or more, sufficient mechanical properties can be obtained, and handling properties are good. When the film thickness is 25 μm or less, the internal resistance is suppressed to an appropriate range.
The Gurley value (JIS P8117) of the polyolefin porous substrate is preferably 50 to 800 seconds / 100 cc. When the Gurley value is 50 seconds / 100 cc or more, problems such as a micro short-circuit hardly occur. On the other hand, if it is 800 seconds / 100 cc or less, the ion permeability is sufficient.
The puncture strength of the polyolefin porous substrate is preferably 300 g or more from the viewpoint of production yield.

[Heat-resistant porous layer]
Examples of the heat-resistant porous layer include a layer having a microporous membrane shape, a nonwoven fabric shape, a paper shape, and other three-dimensional network-like porous structures. The heat-resistant porous layer is preferably a microporous film-like layer from the viewpoint of obtaining better heat resistance. Here, the microporous film-like layer has a large number of micropores inside, and has a structure in which these micropores are connected. Gas or liquid can pass from one surface to the other. The layer that became. The heat resistance is a property that does not cause melting or decomposition in a temperature range of less than 200 ° C.

  The heat resistant porous layer is on both sides of the polyolefin porous substrate. Since the separator of this invention has a heat resistant porous layer on both surfaces of a base material, it is excellent in heat resistance, and when it is set as a battery, it is excellent in safety | security at high temperature. Moreover, since the separator of this invention has a heat resistant porous layer on both surfaces of a base material, the retainability of electrolyte solution is good and it is excellent in cycling characteristics (capacity maintenance factor). Furthermore, it is excellent in durability and handling properties.

The heat-resistant porous layer preferably has a total thickness of 2 μm to 12 μm from the viewpoints of heat resistance, handling properties, and liquid drainage prevention effect.
The porosity of the heat resistant porous layer is preferably 40 to 90%, more preferably 60 to 90%.

(Heat resistant resin)
The heat resistant resin contained in the heat resistant porous layer is preferably a polymer having a melting point of 200 ° C. or higher, or a polymer having no melting point but having a decomposition temperature of 200 ° C. or higher. Examples include wholly aromatic polyamide, polyamideimide, polyimide, polysulfone, polyethersulfone, polyketone, polyetherketone, polyetherimide, cellulose, and polyvinylidene fluoride-containing resin. Among these, at least one selected from the group consisting of wholly aromatic polyamides, polyamideimides, polyimides, polyetherimides, and polysulfones is preferable from the viewpoint of excellent electrolytic solution retention.
Such a heat-resistant resin is particularly preferably a wholly aromatic polyamide from the viewpoint of durability, is easy to form a porous layer, and is excellent in oxidation-reduction resistance in an electrode reaction. Certain polymetaphenylene isophthalamides and polyparaphenylene terephthalamides are more preferred, and polymetaphenylene isophthalamides are particularly preferred.

(Organic filler and inorganic filler)
The heat-resistant porous layer may contain at least one of an organic filler and an inorganic filler (hereinafter collectively referred to as “filler”). The heat-resistant porous layer preferably contains at least one filler from the viewpoint of making the surface roughness of the heat-resistant porous layer appropriate. When the surface roughness of the heat-resistant porous layer is moderately large, it is advantageous in that the adhesion with the adhesive porous layer is improved.
In consideration of mixing with the heat resistant resin, the filler is preferably an inorganic filler rather than an organic filler from the viewpoint of high polarity and easy high dispersion.

Although it does not specifically limit as an organic filler, For example, a melanin resin, a polyethylene resin, a polypropylene resin, an acrylic resin etc. are mentioned.
The organic filler preferably has an average particle size in the range of 0.1 μm to 3.0 μm. When the average particle size is larger than 0.1 μm, the surface of the heat-resistant porous layer becomes moderately rough, and the adhesion between the heat-resistant porous layer and the adhesive porous layer is good. On the other hand, when the average particle size is smaller than 3.0 μm, the heat resistant porous layer can be prevented from becoming brittle, and the handling property of the separator is good.

Examples of the inorganic filler include, but are not limited to, metal oxides such as alumina, titania, silica, and zirconia, metal carbonates such as calcium carbonate, metal phosphates such as calcium phosphate, aluminum hydroxide, and magnesium hydroxide. A metal hydroxide or the like is preferably used. The inorganic filler is preferably an oxide or a hydroxide from the viewpoint of stability or heat resistance.
The inorganic filler preferably has an average particle size in the range of 0.1 μm to 3.0 μm. When the average particle diameter is larger than 0.1 μm, the surface of the heat resistant porous layer becomes moderately rough, and the adhesion between the heat resistant porous layer and the adhesive porous layer is good. On the other hand, when the average particle size is smaller than 3.0 μm, the heat resistant porous layer can be prevented from becoming brittle, and the handling property of the separator is good.

  In the heat resistant porous layer, the content of the inorganic filler is preferably in the range of 1 to 10 parts by mass with respect to 1 part by mass of the heat resistant resin. When the content of the inorganic filler is 1 part by mass or more with respect to 1 part by mass of the heat resistant resin, the adhesion between the heat resistant porous layer and the adhesive porous layer is good. On the other hand, when the amount is 10 parts by mass or less with respect to 1 part by mass of the heat-resistant resin, the heat-resistant porous layer can be prevented from becoming brittle and powder falling off, and the handling property of the separator is good. As for content of an inorganic filler, the range of 1-5 mass parts is more preferable with respect to 1 mass part of heat resistant resins.

(Method for forming heat-resistant porous layer)
Although there is no restriction | limiting in particular in the formation method of the said heat resistant porous layer, For example, it can form through the process of following (1)-(5). In order to fix the heat-resistant porous layer on the base material, a method of directly forming the heat-resistant porous layer on the base material by a coating method is preferable, but not limited thereto, a heat-resistant porous layer manufactured separately is not limited thereto. A technique of adhering the layer sheet onto the base material using an adhesive or the like, or a technique such as heat fusion or pressure bonding can also be employed.

(1) Preparation of coating slurry A heat-resistant resin is dissolved in a solvent to prepare a coating slurry. The solvent is not particularly limited as long as it dissolves the heat-resistant resin, but is preferably a polar solvent, for example, dimethyl sulfoxide, N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2- Examples include pyrrolidone and the like. In addition to the polar solvent, the solvent may be a solvent that becomes a poor solvent for the heat-resistant resin. By applying such a poor solvent, a microphase separation structure is induced and the formation of a heat-resistant porous layer is facilitated. As the poor solvent, alcohols are preferable, and polyhydric alcohols such as glycol are particularly preferable.
The concentration of the heat-resistant resin in the coating slurry is preferably 4 to 9% by mass. Moreover, an organic filler or an inorganic filler is disperse | distributed to this as needed, and it is set as the slurry for coating. In dispersing the inorganic filler in the coating slurry, when the dispersibility of the inorganic filler is not preferable, a method of surface-treating the inorganic filler with a silane coupling agent or the like to improve the dispersibility is also applicable.

(2) Coating of slurry The slurry is coated on both surfaces of the polyolefin porous substrate. It is preferable from the viewpoint of shortening the process that coating is performed simultaneously on both surfaces of the substrate. Examples of the method for coating the slurry for coating include a knife coater method, a gravure coater method, a Mayer bar method, a die coater method, a reverse roll coater method, a roll coater method, a screen printing method, an ink jet method, and a spray method. . Among these, the reverse roll coater method is preferable from the viewpoint of uniformly forming the coating layer. For example, by applying the excess slurry for coating on both sides of the substrate by passing the substrate between a pair of Meyer bars, and scraping off the excess slurry by passing it between a pair of reverse roll coaters. A method of precision weighing can be adopted.

(3) Solidification of slurry By applying a slurry for coating on a polyolefin porous substrate with a coagulation liquid capable of coagulating the heat resistant resin, the heat resistant resin is coagulated and heat resistant. Forming a porous layer. As a method of treating with the coagulating liquid, a method of spraying the coagulating liquid onto the surface coated with the coating slurry or a polyolefin porous substrate coated with the coating slurry on a bath containing the coagulating liquid (coagulating liquid) The method of immersing in bath) etc. is mentioned. The coagulation liquid is not particularly limited as long as it can coagulate the heat-resistant resin, but water or a mixture of an appropriate amount of water in the solvent used in the slurry is preferable. Here, the mixing amount of water is preferably 40 to 80% by mass with respect to the coagulating liquid from the viewpoint of coagulation efficiency and porosity.

(4) Removal of coagulating liquid The coagulating liquid used for coagulating the slurry is removed by washing with water.

(5) Drying Water is removed by drying from a sheet in which a heat-resistant resin coating layer is formed on a polyolefin porous substrate. There is no particular limitation on the drying method, but the drying temperature is preferably 50 to 80 ° C. When applying a high drying temperature, a method of contacting the roll in order to prevent dimensional change due to heat shrinkage, etc. It is preferable to apply.

[Adhesive porous layer]
The adhesive porous layer has a structure in which a large number of micropores are formed in the inside and these micropores are connected, and gas or liquid can pass from one surface to the other surface. It is.
The said adhesive porous layer is laminated | stacked on the heat resistant porous layer in the single side | surface or both surfaces of a polyolefin porous base material. The adhesive porous layer comes into contact with the electrode when the separator of the present invention is applied to a battery. The adhesive porous layer is preferably on both sides rather than only on one side of the base material from the viewpoint of better cycle characteristics (capacity maintenance ratio) of the battery. When the adhesive porous layer is on both sides of the substrate, both sides of the separator come into contact with both the positive electrode and the negative electrode through the adhesive porous layer, and the separator and both electrodes are well bonded.

The adhesive porous layer preferably has a sufficiently porous structure from the viewpoint of ion permeability. Specifically, the porosity is preferably 30 to 80%. When the porosity is 80% or less, it is possible to secure mechanical properties that can withstand a pressing process for bonding to an electrode. Further, when the porosity is 80% or less, the surface porosity is not too high and a sufficient adhesive force can be ensured. On the other hand, if the porosity is 30% or more, the ion permeability is good.
Further, the adhesive porous layer preferably has an average pore size of 10 nm to 200 nm. When the average pore diameter is 200 nm or less, the nonuniformity of the pores is suppressed, the adhesion points are evenly dispersed, and the adhesiveness is good. Further, when the average pore diameter is 200 nm or less, the movement of ions is uniform and the cycle characteristics and load characteristics are good. On the other hand, when the average pore diameter is 10 nm or more, when the adhesive porous layer is impregnated with the electrolytic solution, it is difficult for the resin to swell and block the pores to inhibit the ion permeability.

The thickness of the adhesive porous layer is preferably 0.5 μm to 10 μm and more preferably 1 μm to 5 μm per side from the viewpoints of adhesion to the electrode and ion permeability.
Coating amount of the adhesive porous layer, when it is formed on one side of the substrate, both when it is formed on both sides of the substrate, the range of 0.5g ^/ m ² ~3.5g / m 2 It is preferable that When the coating amount is 0.5 g / m ² or more, the adhesion with the electrode is good and the cycle characteristics of the battery are good. On the other hand, when the coating amount is 3.5 g / m ² or less, the ion permeability is good and the load characteristics of the battery are good. The coating amount of the adhesive porous layer ^is more preferably in the range of ^{1.0g / m 2 ~2.5g / m 2} , in the range of 1.5g / ^{m 2} ~2.5g / m 2 More preferably.

(Fluorine resin)
There is no limitation in particular as a fluorine resin contained in the said adhesive porous layer. For example, polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride copolymer, polyvinyl fluoride, perfluoroalkoxy fluorine resin, tetrafluoroethylene / hexafluoroethylene copolymer, ethylene / tetrafluoroethylene And ethylene copolymer. In particular, polyvinylidene fluoride and a polyvinylidene fluoride copolymer are preferable. Such a fluororesin can be obtained by emulsion polymerization or suspension polymerization.

(Polyvinylidene fluoride resin)
In the present invention, the fluororesin is preferably a polyvinylidene fluoride resin from the viewpoint of adhesion to the electrode, and is preferably at least one of the following (i) and (ii). In particular, from the viewpoint of adhesion between the heat-resistant porous layer and the adhesive porous layer, the following copolymer (ii) is preferable.
(I) polyvinylidene fluoride (ii) vinylidene fluoride and at least one monomer selected from the group consisting of perfluoroalkyl vinyl ether, hexafluoropropylene, trifluorochloroethylene, tetrafluoroethylene and ethylene, Copolymer having a molar fraction of 1 to 10% (hereinafter, also referred to as “specific polyvinylidene fluoride copolymer”).

The specific polyvinylidene fluoride copolymer is at least one monomer selected from the group consisting of perfluoroalkyl vinyl ether, hexafluoropropylene, trifluorochloroethylene, tetrafluoroethylene and ethylene (hereinafter also referred to as “comonomer”). .) Is 1 to 10%. The polyvinylidene fluoride copolymer tends to swell in the electrolyte solution when the comonomer content is high. When the molar fraction of the comonomer is 10% or less, the shape retention of the adhesive porous layer is high and the retention of the electrolyte is improved, so that the cycle characteristics are good. On the other hand, when the molar fraction of the comonomer is 1% or more, the adhesion with the heat-resistant porous layer is good.
Among the specific polyvinylidene fluoride copolymers, from the viewpoint of electrolytic solution retention and adhesiveness to the heat-resistant porous layer, vinylidene fluoride and hexafluoropropylene have a mole fraction of 1 to 10% of hexafluoropropylene. Copolymerized copolymers are preferred.

The polyvinylidene fluoride resin used in the present invention preferably has a weight average molecular weight in the range of 300,000 to 1,500,000. If the weight average molecular weight is 300,000 or more, the adhesive porous layer can secure mechanical properties that can withstand the adhesion treatment with the electrode, and sufficient adhesion can be obtained. On the other hand, when the weight average molecular weight is 1,500,000 or less, the viscosity at the time of molding does not become too high, the moldability and crystal formation are good, and the porosity is good. More preferably, it is the range of 500,000 to 1,200,000.
The fibril diameter of the polyvinylidene fluoride resin is preferably in the range of 10 nm to 1000 nm from the viewpoint of cycle characteristics.

(Method for forming adhesive porous layer)
In the present invention, the method for forming the adhesive porous layer is not particularly limited. The polyvinylidene fluoride resin layer (hereinafter referred to as “PVdF layer”) can be formed, for example, by a wet coating method described in Japanese Patent No. 4163894. In the wet coating method, a polyvinylidene fluoride resin is dissolved in an appropriate solvent to prepare a coating dope, the coating dope is applied to a substrate, and then immersed in an appropriate coagulation liquid. This is a film forming method in which a polyvinylidene fluoride resin is solidified while inducing phase separation, washed with water and dried to form a porous layer on a substrate. The details of the wet coating method suitable for the present invention are as follows.

  As a solvent for dissolving a polyvinylidene fluoride resin used for the preparation of a coating dope (hereinafter also referred to as “good solvent”), polar amide solvents such as N-methylpyrrolidone, dimethylacetamide, dimethylformamide, dimethylformamide, etc. Are preferably used. From the viewpoint of forming a good porous structure, it is preferable to mix a phase separation agent that induces phase separation in addition to a good solvent. Examples of the phase separation agent include water, methanol, ethanol, propyl alcohol, butyl alcohol, butanediol, ethylene glycol, propylene glycol, and tripropylene glycol. The coating dope preferably has a concentration of polyvinylidene fluoride resin of 3 to 10% by mass from the viewpoint of forming a good porous structure.

  The coagulating liquid is generally composed of a good solvent used for preparing the coating dope, a phase separation agent, and water. It is preferable in production that the mixing ratio of the good solvent and the phase separation agent is adjusted to the mixing ratio of the mixed solvent used for dissolving the polyvinylidene fluoride resin. It is appropriate that the water concentration is 40 to 90% by mass from the viewpoint of the formation of a porous structure and productivity.

  Conventional coating methods such as a Meyer bar, a die coater, a reverse roll coater, and a gravure coater can be applied to the substrate for applying the dope for coating. When forming a PVdF layer on both surfaces of a base material, it is preferable from a viewpoint of productivity to apply dope for coating to a base material simultaneously on both surfaces.

In the wet coating method as described above, it is preferable to adjust the conditions as follows from the viewpoint of increasing the adhesion between the PVdF layer and the heat-resistant porous layer.
As a solvent for dissolving the polyvinylidene fluoride resin, a mixed solvent of a good solvent and a phase separation agent (hereinafter also referred to as “poor solvent”) is usually used. By adjusting the mixing ratio, heat resistance is improved. It is preferable to enhance the adhesion between the heat-resistant porous layer and the PVdF layer by appropriately dissolving or swelling the surface of the porous layer. Specifically, when an aromatic polyamide is used for the heat resistant porous layer, a good solvent (for example, dimethylacetamide: DMAc) and a poor solvent (for example, tripropylene glycol: TPG) used for dissolving the polyvinylidene fluoride resin. The mixing ratio is preferably in the range of 90:10 to 60:40 by mass ratio. When the proportion of the good solvent is 60% by mass or more, the surface of the heat resistant porous layer is appropriately dissolved or swollen, and the adhesiveness between the heat resistant porous layer and the PVdF layer is good. On the other hand, when the proportion of the poor solvent is 10% by mass or more, it is advantageous in terms of good porosity.
In the step of solidifying by dipping in a coagulation liquid (usually composed of a good solvent, a poor solvent, and water), it is preferable that the coagulation rate is fast. That is, as the solvent concentration of the coagulating liquid is lower and the coagulating liquid temperature is higher, the adhesion tends to be improved. However, if the solidification rate is too high, the surface of the PVdF layer becomes too dense, so that a balance between obtaining an appropriate porous structure and adhesiveness with the heat-resistant porous layer is taken into consideration.
Specifically, the ratio of water: solvent (total of good solvent and poor solvent) in the coagulation bath is preferably in the range of mass ratio 90:10 to 50:50. When the amount of water is 90% by mass or less, that is, the solvent concentration is 10% by mass or more, the surface of the PVdF layer is not too dense and a good porous structure is obtained, and the surface of the heat-resistant porous layer is moderate. It can melt | dissolve or swell and can ensure the adhesiveness of a heat resistant porous layer and a PVdF layer. On the other hand, when the amount of water is 50% by mass or more, the coagulation rate is moderately fast and the adhesion to the heat-resistant porous layer is good.

  The adhesive porous layer can be produced by a dry coating method other than the wet coating method described above. Here, the dry coating method refers to, for example, applying a coating dope containing a polyvinylidene fluoride resin and a solvent to a substrate, and drying the solvent to volatilize and remove the solvent, thereby obtaining a porous layer. Is the method. However, the dry coating method is more preferable than the wet coating method in that the coating layer tends to be denser and a good porous structure can be obtained.

  The adhesive porous layer may contain an inorganic filler such as a metal oxide such as alumina or a metal hydroxide such as magnesium hydroxide. In this case, an inorganic filler may be dispersed in the coating dope when forming the porous layer. However, if the adhesive porous layer contains an inorganic filler, the adhesiveness to the electrode may be lowered. Therefore, the adhesive porous layer preferably does not contain an inorganic filler.

(Separator characteristics)
The shutdown temperature of the nonaqueous electrolyte battery separator of the present invention is preferably 130 to 155 ° C. When the shutdown temperature is 130 ° C. or higher, the melt does not melt at a low temperature and the safety is high. On the other hand, when the shutdown temperature is 155 ° C. or lower, various materials of the battery are not exposed to high temperatures, and safety can be expected. The shutdown temperature is more preferably 135 to 150 ° C.

  The non-aqueous electrolyte battery separator preferably has a thermal shrinkage in the MD direction of 15% or less, and more preferably 10% or less. Further, the thermal shrinkage rate in the TD direction is preferably 10% or less, and more preferably 5% or less. When the thermal contraction rate is within this range, the heat resistance of the separator is good, and the safety of the battery can be ensured even at high temperatures. Here, the heat shrinkage rate is measured in an environment of 135 ° C. by the evaluation method described in the examples.

The separator for a nonaqueous electrolyte battery preferably has a total film thickness of 5 μm to 35 μm from the viewpoint of mechanical strength and energy density when used as a battery.
The porosity of the nonaqueous electrolyte battery separator is preferably 30 to 60% from the viewpoints of mechanical strength, handling properties, and ion permeability.
The Gurley value (JIS P8117) of the non-aqueous electrolyte battery separator is preferably 50 to 800 seconds / 100 cc, and preferably 100 to 500 seconds / 100 cc, in terms of a good balance between mechanical strength and membrane resistance. More preferred.
The membrane resistance of the non-aqueous electrolyte battery separator is preferably ¹ to 10 ohm · cm ² from the viewpoint of battery load characteristics. Here, the membrane resistance is a resistance value when the separator is impregnated with an electrolytic solution, and is measured by an alternating current method. Of course, the type of the electrolyte varies depending on the temperature, the above figures are used 1M LiBF ₄ propylene carbonate / ethylene carbonate as an electrolyte solution (weight ratio 1/1), is a value measured at 20 ° C..
The puncture strength of the nonaqueous electrolyte battery separator is preferably 250 g or more from the viewpoint of short circuit resistance, mechanical strength, and handling properties.
The tensile strength of the nonaqueous electrolyte battery separator is preferably 10 N or more from the viewpoint of short circuit resistance, mechanical strength, and handling properties.
The curvature of the nonaqueous electrolyte battery separator is preferably 1.5 to 2.5 from the viewpoint of ion permeability.

<Nonaqueous electrolyte battery>
The non-aqueous electrolyte battery of the present invention is a non-aqueous electrolyte battery that obtains an electromotive force by doping or dedoping lithium, and includes a positive electrode, a negative electrode, and a separator for a non-aqueous electrolyte battery having the above-described configuration. A non-aqueous electrolyte battery has a structure in which a battery element in which a negative electrode and a positive electrode face each other with a separator interposed therebetween is impregnated with an electrolytic solution, and this is enclosed in an exterior. Among the nonaqueous electrolyte batteries having such a configuration, a nonaqueous electrolyte secondary battery, particularly a lithium ion secondary battery is preferable.

  The nonaqueous electrolyte battery of the present invention uses the above-described separator for nonaqueous electrolyte batteries of the present invention as a separator. The nonaqueous electrolyte battery having such a configuration has a shutdown function and heat resistance, and is excellent in cycle characteristics (capacity maintenance ratio).

  The negative electrode has a structure in which a negative electrode mixture composed of a negative electrode active material, a conductive additive and a binder is formed on a current collector. Examples of the negative electrode active material include materials capable of electrochemically doping lithium, and examples thereof include carbon materials, silicon, aluminum, tin, and wood alloys. Examples of the conductive assistant include carbon materials such as acetylene black and ketjen black. The binder is made of an organic polymer, and examples thereof include polyvinylidene fluoride and carboxymethyl cellulose. A copper foil, a stainless steel foil, a nickel foil or the like can be used for the current collector.

The positive electrode has a structure in which a positive electrode mixture composed of a positive electrode active material, a conductive additive and a binder is formed on a current collector. Examples of the positive electrode active material include lithium-containing transition metal oxides. Specifically, LiCoO ₂ , LiNiO ₂ , LiMn _0.5 Ni _0.5 O ₂ , LiCo _1/3 Ni _1/3 Mn _1/3 Examples include O ₂ , LiMn ₂ O ₄ , LiFePO ₄ , LiCo _0.5 Ni _0.5 O ₂ , LiAl _0.25 Ni _0.75 O _{2, and the} like. Examples of the conductive assistant include carbon materials such as acetylene black and ketjen black. The binder is made of an organic polymer, and examples thereof include polyvinylidene fluoride. For the current collector, aluminum foil, stainless steel foil, titanium foil, or the like can be used.

The electrolytic solution is a solution in which a lithium salt is dissolved in a non-aqueous solvent. Examples of the lithium salt include LiPF ₆ , LiBF ₄ , LiClO _{4 and the} like. Examples of the non-aqueous solvent include propylene carbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, γ-butyrolactone, vinylene carbonate, and the like. These may be used alone or in combination.

  Examples of the exterior material include a metal can or an aluminum laminate pack. The shape of the battery includes a square shape, a cylindrical shape, a coin shape, and the like, but the nonaqueous electrolyte battery separator of the present invention can be suitably applied to any shape.

The present invention will be described more specifically with reference to the following examples. The materials, amounts used, ratios, processing procedures, and the like shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the specific examples shown below.
In the following Examples and Comparative Examples, an adhesive porous layer containing a polyvinylidene fluoride resin is referred to as a “PVdF layer”.

The measurement methods applied in the examples and comparative examples of the present invention are as follows.
[Film thickness]
The film thickness (μm) was determined by measuring 20 points with a contact-type thickness meter (LITEMATIC, manufactured by Mitutoyo Corporation) and averaging them. Here, a cylindrical terminal having a diameter of 5 mm was used as the measurement terminal, and it was adjusted so that a load of 7 g was applied during the measurement.

[PVdF coating amount]
The sample after PVdF coating was cut into 10 cm × 10 cm, the mass was measured, and the mass per unit area (mass per m ² ) was determined by dividing the mass by the area. Separately, a sample before PVdF coating was cut into 10 cm × 10 cm, the mass was measured, and the mass per unit area was obtained by dividing the mass by the area. The latter basis weight was subtracted from the former basis weight, and the PVdF coating amount (g / m ² ) was determined.

[Shutdown characteristics]
The produced separator was impregnated with an electrolytic solution and sandwiched between SUS plates, which were enclosed in a coin cell. As the electrolytic solution, a solution obtained by dissolving 1 mol / L of LiBF ₄ in a mixed solvent of propylene carbonate and ethylene carbonate (mass ratio 1: 1) was used. I took the lead from the coin cell, put a thermocouple, and put it in the oven. The resistance was measured by increasing the temperature at a temperature increase rate of 1.6 ° C./min and simultaneously applying alternating current with an amplitude of 10 mV and a frequency of 1 kHz.
The shutdown properties, a case where the temperature at which the resistance value has reached ¹⁰ 3 ohm · cm ² is one hundred thirty to one hundred and fifty-five ° C. was determined to be good, or the resistance value does not reach ¹⁰ 3 ohm · cm ^2, or who Even if it was, the case where the temperature at that time exceeded 155 ° C. was judged as defective.

[Heat shrinkage]
The sample was cut into 18 cm (MD direction) × 6 cm (TD direction). Two points (point A and point B) of 2 cm and 17 cm from one end were marked on a line that bisects the TD direction. Further, two points (point C and point D) of 1 cm and 5 cm from one end were marked on a line that bisects the MD direction. A clip was held between the end closest to point A and point A, suspended in a 135 ° C. oven so that the MD direction was the direction of gravity, and heat-treated for 30 minutes under no tension. The length between AB and between CD before and after heat treatment was measured, and the thermal shrinkage rate (%) was calculated from the following formula.
MD direction thermal shrinkage (%) = (length between AB before heat treatment−length between AB after heat treatment) / (length between AB before heat treatment) × 100
TD direction thermal shrinkage (%) = (length between CDs before heat treatment−length between CDs after heat treatment) / (length between CDs before heat treatment) × 100

[Electrode adhesion]
The test battery was disassembled, and the magnitude of the force when peeling the negative electrode and the positive electrode from the separator was measured using a tensile tester. Evaluation was made as an index when the force required to peel the electrode from the separator in Example 1 was taken as 100. An index of 60 or more is a practically preferable level.

[Cycle characteristics (capacity maintenance ratio)]
Charging conditions were 1C, 4.2V constant current constant voltage charging, and discharging conditions were 1C, 2.75V cut-off constant current discharging, and charging and discharging were repeated in an environment of 30 ° C. A value obtained by dividing the discharge capacity at the 300th cycle by the initial capacity was defined as the capacity retention rate (%).

[Load characteristics]
Measure the discharge capacity when discharged at 0.2C and the discharge capacity when discharged at 2C in an environment of 25 ° C, and divide the latter by the former value (%) as an indicator of load characteristics It was. Here, the charging condition was 0.2 C, 4.2 V constant current constant voltage charging for 8 hours, and the discharging condition was 2.75 V cut-off constant current discharging.

[Adhesion between layers]
A cellophane tape was applied to the surface of the PVdF layer of the separator, and the force when the cellophane tape was pulled and peeled was measured with a spring alone to evaluate the adhesion between the heat resistant porous layer and the PVdF layer.
Here, when the peeling force was measured for the separator of Example 1, no peeling occurred at the interface between the PVdF layer and the heat-resistant porous layer, and only the cellophane tape peeled cleanly from the PVdF layer. The measured value of only the spring at this time was taken as an index 100, and the measured values of other examples were indexed by comparison with this. In other examples, when the index was less than 100, peeling occurred at the interface between the PVdF layer and the heat-resistant porous layer before the cellophane tape was peeled from the PVdF layer.

[Food fall]
Two films with a heat-resistant porous layer formed on a polyolefin porous substrate are rubbed together, and ○ on the rubbed surface where no powder fall is confirmed at all. The case was evaluated as x.

<Example 1>
[Preparation of separator for non-aqueous electrolyte battery]
(Formation of heat-resistant porous layer)
Meta-type aramid resin (Conex, manufactured by Teijin) and magnesium hydroxide having an average particle size of 0.8 μm as inorganic filler (Kisuma 5P, manufactured by Kyowa Chemical Co., Ltd.) have a mass ratio of 1: 4. Slurry for coating by mixing in a mixed solvent of dimethylacetamide (DMAc) and tripropylene glycol (TPG) (DMAc: TPG = 60: 40 [mass ratio]) so that the aramid resin concentration is 5.0% by mass. (I) was obtained.
Apply a suitable amount of slurry (I) for coating to a pair of Meyer bars, and pass a polyethylene microporous membrane (TN1201, SK, film thickness 12 μm) between the Mayer bars to coat the slurry (I) for coating on both sides. Worked. This was immersed in a coagulating liquid (water: DMAc: TPG = 70: 18: 12 [mass ratio]) at 30 ° C. Next, the film was washed in a water washing tank having a water temperature of 40 ° C. and dried to obtain a film (film thickness 20 μm) in which a heat-resistant porous layer was formed on both surfaces of a polyolefin porous substrate.

(Formation of PVdF layer)
As a polyvinylidene fluoride resin, a random copolymer of vinylidene fluoride and hexafluoropropylene (copolymerization ratio [molar ratio] VdF: HFP = 95: 5, KYNAR2801, manufactured by Arkema) is 8% by mass, and a mixed solvent of DMAc and TPG. It melt | dissolved in (DMAc: TPG = 70: 30 [mass ratio]), and dope (A) for coating was produced.
Apply a suitable amount of coating dope (A) to a pair of Meyer bars, pass the film between the Meyer bars, and apply the coating dope (A) on both sides so that the coating amount on the front and back surfaces is the same. Coated. This was immersed in a coagulating liquid at 30 ° C. (water: DMAc: TPG = 70: 21: 9 [mass ratio]). Next, after washing in a water washing tank having a water temperature of 40 ° C., drying, a separator for a nonaqueous electrolyte battery (film thickness: 24 μm) in which a PVdF layer (PVdF coating amount 1.9 g / m ² ) is formed on both surfaces of the film Obtained.

[Preparation of non-aqueous electrolyte battery]
(Preparation of negative electrode)
300 g of artificial graphite (MCMB25-28, manufactured by Osaka Gas Chemical Co., Ltd.) as a negative electrode active material, and “BM-400B” (manufactured by Nippon Zeon as a binder) (water-soluble dispersion containing 40% by mass of a modified styrene-butadiene copolymer) ) 7.5 g, 3 g of carboxymethyl cellulose as a thickener, and an appropriate amount of water were stirred with a double-arm mixer to prepare a slurry for negative electrode. This negative electrode slurry was applied to a 10 μm thick copper foil as a negative electrode current collector, dried and pressed to obtain a negative electrode having a negative electrode active material layer.

(Preparation of positive electrode)
Lithium cobaltate (cell seed C, Nippon Kagaku Kogyo Co., Ltd.) powder 89.5 g as a positive electrode active material, conductive auxiliary agent acetylene black (Denka Black, Denki Kagaku Kogyo Co., Ltd.) 4.5 g, and polyvinylidene fluoride as a binder (KF polymer W # 1100, manufactured by Kureha Chemical Co., Ltd.) 6 g was dissolved in N-methyl-pyrrolidone (NMP) so as to be 6% by mass and stirred with a double-arm mixer to prepare a positive electrode slurry. . This positive electrode slurry was applied to a 20 μm thick aluminum foil as a positive electrode current collector, dried and pressed to obtain a positive electrode having a positive electrode active material layer.

(Production of battery)
A lead tab was welded to the positive electrode and the negative electrode, the positive and negative electrodes were joined via a separator, an electrolyte solution was impregnated, and sealed in an aluminum pack using a vacuum sealer. Here, 1 M LiPF ₆ -ethylene carbonate / ethyl methyl carbonate (mass ratio 3/7) was used as the electrolytic solution. This was hot-pressed using a hot press machine (20 kg load per 1 cm ^{2 of} electrode, 90 ° C., 2 minutes) to obtain a test battery.

<Example 2>
A separator for a non-aqueous electrolyte battery having a PVdF coating amount of 1.0 g / m ² (membrane) except that the clearance between the Meyer bars is adjusted during the coating of the coating dope (A). A thickness of 22 μm) was obtained. Then, a nonaqueous electrolyte battery was produced in the same manner as in Example 1.

<Example 3>
A separator for a non-aqueous electrolyte battery having a PVdF coating amount of 0.5 g / m ² (membrane), except that the clearance between the Meyer bars is adjusted when the coating dope (A) is applied. A thickness of 21 μm) was obtained. Then, a nonaqueous electrolyte battery was produced in the same manner as in Example 1.

<Example 4>
A separator for a nonaqueous electrolyte battery having a PVdF coating amount of 3.5 g / m ² (membrane) except that the clearance between the Meyer bars is adjusted at the time of coating the coating dope (A). A thickness of 26 μm) was obtained. Then, a nonaqueous electrolyte battery was produced in the same manner as in Example 1.

<Example 5>
A separator for a nonaqueous electrolyte battery having a PVdF coating amount of 0.9 g / m ² (film thickness: 22 μm) in the same manner as in Example 1 except that the coating dope (A) was coated on one side of the film. Got. A nonaqueous electrolyte battery was prepared in the same manner as in Example 1 except that the PVdF layer was in contact with the negative electrode side.

<Example 6>
Example 1 except that a coating slurry was prepared by changing the mass ratio of the meta-type aramid resin and the inorganic filler to 1: 1, and a heat-resistant porous layer was formed using this coating slurry (II). Similarly, a separator for nonaqueous electrolyte batteries (film thickness: 24 μm) having a PVdF coating amount of 1.8 g / m ² was obtained.

<Example 7>
A polyvinylidene fluoride resin was changed to a random copolymer of vinylidene fluoride and hexafluoropropylene (KYNAR2750, manufactured by Arkema) to prepare a coating dope, and a PVdF layer was formed using this coating dope (B). Except for the above, a separator for a nonaqueous electrolyte battery (film thickness: 23 μm) having a PVdF coating amount of 1.5 g / m ² was obtained in the same manner as in Example 1.

<Example 8>
The coating amount of PVdF was 1. in the same manner as in Example 1 except that a coating slurry was prepared without adding an inorganic filler, and a heat-resistant porous layer was formed using this coating slurry (III). A non-aqueous electrolyte battery separator (film thickness: 24 μm) of 7 g / m ² was obtained.

<Example 9>
Example 1 except that a coating slurry was prepared by changing the mass ratio of the meta-type aramid resin and the inorganic filler to 1:20, and the heat-resistant porous layer was formed using this coating slurry (IV). Similarly, a separator for a nonaqueous electrolyte battery (film thickness: 24 μm) having a PVdF coating amount of 1.9 g / m ² was obtained.

<Example 10>
Example except that the polyvinylidene fluoride resin was changed to a homopolymer of vinylidene fluoride (KYNAR721, manufactured by Arkema) to prepare a coating dope, and this coating dope (C) was used to form a PVdF layer. In the same manner as in Example ^1, a nonaqueous electrolyte battery separator (film thickness: 23 μm) having a PVdF coating amount of 1.4 g / m ² was obtained.

<Example 11>
Example except that the polyvinylidene fluoride resin was changed to a homopolymer of vinylidene fluoride (KYNAR761, manufactured by Arkema) to prepare a coating dope, and a PVdF layer was formed using this coating dope (D) In the same manner as in Example ^1, a nonaqueous electrolyte battery separator (film thickness: 23 μm) having a PVdF coating amount of 1.5 g / m ² was obtained.

<Comparative Example 1>
A nonaqueous electrolyte battery was produced in the same manner as in Example 1 using a polyethylene microporous membrane (TN1201, manufactured by SK, film thickness: 12 μm) as a separator.

<Comparative example 2>
In the same manner as in “Formation of heat-resistant porous layer” in Example 1, a film (film thickness 20 μm) having a heat-resistant porous layer formed on both surfaces of a polyolefin porous substrate was obtained, and this was used as a separator. A nonaqueous electrolyte battery was produced in the same manner as in Example 1.

<Comparative Example 3>
Apply an appropriate amount of coating dope (A) to a pair of Meyer bars, and pass a polyethylene microporous membrane (TN1201, SK, film thickness 12 μm) between the Meyer bars to coat the coating dope (A) on both sides. Worked. This was immersed in a coagulating liquid at 30 ° C. (water: DMAc: TPG = 70: 21: 9 [mass ratio]). Next, after washing in a water washing tank having a water temperature of 40 ° C., drying, a separator for a non-aqueous electrolyte battery having a PVdF layer (PVdF coating amount of 1.8 g / m ² ) formed on both surfaces of the polyolefin porous substrate (film thickness) 15 μm) was obtained. Then, a nonaqueous electrolyte battery was produced in the same manner as in Example 1.

<Comparative example 4>
Apply a suitable amount of slurry (I) for coating to a pair of Meyer bars, and pass a polyethylene microporous membrane (TN1201, SK, film thickness 12 μm) between the Meyer bars to coat the coating slurry (I) on one side. Worked. This was coagulated, washed and dried in the same manner as in Example 1 to obtain a film (film thickness 16 μm) in which a heat-resistant porous layer was formed on both surfaces of a polyolefin porous substrate. Using this film, a separator for a nonaqueous electrolyte battery in which PVdF layers (PVdF coating amount 1.7 g / m ² ) were formed on both sides of the film in the same manner as in “Formation of PVdF layer” in Example 1 ( A film thickness of 20 μm) was obtained. Then, a nonaqueous electrolyte battery was produced in the same manner as in Example 1, except that the PVdF layer provided on the heat resistant porous layer was in contact with the negative electrode side.

  As apparent from Table 1, the separator for a nonaqueous electrolyte battery of the present invention has a low thermal shrinkage in both the MD direction and the TD direction, has excellent adhesion to electrodes, and has a shutdown characteristic and a capacity retention rate when used as a battery. It was excellent. Therefore, the separator for nonaqueous electrolyte batteries of the present invention has high safety and excellent cycle characteristics when used as a battery.

Claims (8)

A porous substrate comprising a polyolefin;
A heat-resistant porous layer provided on both surfaces of the porous substrate and containing a heat-resistant resin;
An adhesive porous layer provided on at least one of the heat-resistant porous layer and containing a fluorine-based resin;
A separator for a nonaqueous electrolyte battery. The separator for a nonaqueous electrolyte battery according to claim 1, wherein the adhesive porous layer has a coating amount in a range of 0.5 g / m ² or more and 3.5 g / m ² or less.   The separator for nonaqueous electrolyte batteries according to claim 1 or 2, wherein the heat-resistant porous layer contains at least one of an organic filler and an inorganic filler.   The heat-resistant porous layer contains an inorganic filler, and the content of the inorganic filler is in the range of 1 to 10 parts by mass with respect to 1 part by mass of the heat-resistant resin. The separator for a nonaqueous electrolyte battery according to item 1. The fluorine-based resin is
(I) polyvinylidene fluoride, and
(Ii) vinylidene fluoride and at least one monomer selected from the group consisting of perfluoroalkyl vinyl ether, hexafluoropropylene, trifluoroethylene chloride, tetrafluoroethylene and ethylene, A copolymer copolymerized at 10%,
The separator for nonaqueous electrolyte batteries according to any one of claims 1 to 4, which is at least one of the following.   The non-water according to any one of claims 1 to 5, wherein the heat-resistant resin is at least one selected from the group consisting of wholly aromatic polyamides, polyamideimides, polyimides, polyetherimides, and polysulfones. Electrolyte battery separator.   The said adhesive porous layer is provided on each of the said heat resistant porous layer provided in both surfaces of the said porous base material, The any one of Claims 1-6. Nonaqueous electrolyte battery separator.   A non-aqueous electrolyte battery separator according to any one of claims 1 to 7, which is disposed between the positive electrode and the negative electrode, and between the positive electrode and the negative electrode. Non-aqueous electrolyte battery that obtains electric power.