JP2017107848A - Nonaqueous electrolyte secondary battery separator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a separator which is suitable for a nonaqueous electrolyte secondary battery having excellent discharge output characteristics.SOLUTION: A nonaqueous electrolyte secondary battery separator comprising a porous film containing a polyolefin resin as a main component has a piercing strength of equal to or greater than 26.0 gf/g/m, the piercing strength being measured based on a weight per unit area of the porous film, and satisfies the following formula: 0.00≤|1-T/M|≤0.54 (where, T and M represent a distance to a point where a critical load is obtained in a TD direction and a distance to a point where a critical load is obtained in an MD direction, respectively, in a scratch test under a constant load of 0.1 N).SELECTED DRAWING: None

Description

  The present invention relates to a separator for a nonaqueous electrolyte secondary battery comprising a porous membrane, and a laminated separator for a nonaqueous electrolyte secondary battery comprising a porous layer laminated on the porous membrane.

  Non-aqueous electrolyte secondary batteries, especially lithium secondary batteries, are widely used as batteries for personal computers, mobile phones, personal digital assistants, etc. due to their high energy density, and recently developed as in-vehicle batteries. ing.

  As a separator in a non-aqueous electrolyte secondary battery such as a lithium ion secondary battery, a microporous film containing polyolefin as a main component is used.

  In the non-aqueous electrolyte secondary battery, since the electrode repeatedly expands and contracts with charge and discharge, stress is generated between the electrode and the separator, and the internal resistance increases due to the electrode active material dropping off, There is a problem that the cycle characteristics deteriorate. In view of this, there has been proposed a technique for improving the adhesion between the separator and the electrode by coating the surface of the separator with an adhesive substance such as polyvinylidene fluoride (Patent Documents 1 and 2).

Japanese Patent No. 5355823 (issued on November 27, 2013) JP 2001-118558 A (published on April 27, 2001)

  In a non-aqueous electrolyte secondary battery, the electrode expands and contracts during charge and discharge, resulting in deformation in the thickness direction of the surface layer facing the separator electrode and horizontal force at the separator electrode interface. Thus, in the non-aqueous electrolyte secondary battery incorporating the above-described conventional separator, due to the deformation in the thickness direction and the force in the horizontal direction, the uniformity in the surface direction of the distance between the electrodes is reduced. The rate characteristics after the charge / discharge cycle of the non-aqueous electrolyte secondary battery sometimes deteriorated.

  The inventors have used a porous membrane in which the ratio of the distance to the critical load in TD (T) and the distance to the critical load in MD (M) measured by the scratch test is in a certain range. The separator for water electrolyte secondary batteries was found to be excellent in rate characteristic retention after charge / discharge cycles, and the present invention was conceived.

  The present invention may include the following non-aqueous electrolyte secondary battery separator, non-aqueous electrolyte secondary battery laminated separator, non-aqueous electrolyte secondary battery member, and non-aqueous electrolyte secondary battery.

The separator for a non-aqueous electrolyte secondary battery of the present invention is a separator for a non-aqueous electrolyte secondary battery composed of a porous film mainly composed of a polyolefin resin,
The puncture strength with respect to the basis weight per unit area of the porous membrane is 26.0 gf / g / m ² or more, and
The value represented by the following formula (1) is in the range of 0.00 to 0.54.
| 1-T / M | (1)
(In Formula (1), T represents a distance to a critical load in a scratch test under a constant load of 0.1 N in TD, and M is a scratch test in a scratch test under a constant load of 0.1 N in MD. Represents the distance to the critical load.)
In the separator for a non-aqueous electrolyte secondary battery of the present invention, the value represented by the following formula (2) is preferably in the range of 0.00 or more and 0.54 or less.
1-T / M (2)
(In Formula (2), T represents a distance to a critical load in a scratch test under a constant load of 0.1 N in TD, and M is a scratch test in a scratch test under a constant load of 0.1 N in MD. Represents the distance to the critical load.)
The laminated separator for nonaqueous electrolyte secondary batteries of the present invention is characterized in that a porous layer is laminated on at least one surface of the separator for nonaqueous electrolyte secondary batteries of the present invention.

  In the laminated separator for a non-aqueous electrolyte secondary battery according to the present invention, the porous layer preferably contains a heat-resistant resin, and more preferably contains a polyvinylidene fluoride resin. The porous layer preferably contains insulating fine particles.

  The member for a non-aqueous electrolyte secondary battery of the present invention includes a positive electrode, a separator for a non-aqueous electrolyte secondary battery of the present invention, or a laminated separator for a non-aqueous electrolyte secondary battery of the present invention, and a negative electrode in this order. It is arranged.

  The nonaqueous electrolyte secondary battery of the present invention includes the separator for a nonaqueous electrolyte secondary battery of the present invention or the multilayer separator for a nonaqueous electrolyte secondary battery of the present invention.

  The separator for a non-aqueous electrolyte secondary battery or the laminated separator for a non-aqueous electrolyte secondary battery of the present invention improves the rate characteristic maintenance rate after the charge / discharge cycle of the non-aqueous electrolyte secondary battery incorporating the separator. The non-aqueous electrolyte secondary battery is excellent in discharge output characteristics.

It is a figure which shows an apparatus and its operation in the scratch test in this invention. It is the figure which showed the distance to the critical load and the critical load in the graph created from the result of the scratch test in this invention. In Examples 3-5, it is a schematic diagram which shows the method of performing additional extending | stretching of the said stretched film after cooling the stretched film after heat setting.

  Hereinafter, an embodiment of the present invention will be described in detail. In the present application, “A to B” means “A or more and B or less”.

[Embodiment 1: Separator for non-aqueous electrolyte secondary battery, Embodiment 2: Laminated separator for non-aqueous electrolyte secondary battery]
A separator for a non-aqueous electrolyte secondary battery according to Embodiment 1 of the present invention is a separator for a non-aqueous electrolyte secondary battery comprising a porous film mainly composed of a polyolefin-based resin, and is a unit of a porous film. The piercing strength with respect to the basis weight per area is 26.0 gf / g / m ² or more, and the value represented by the following formula (1) is in the range of 0.00 or more and 0.54 or less. Features.
| 1-T / M | (1)
(In Formula (1), T represents the distance to the critical load in a scratch test under a constant load of 0.1 N in TD (Transverse Direction), and M is 0.1 N in MD (Machine Direction). (This represents the distance to the critical load in the scratch test under a constant load.)
The laminated separator for a nonaqueous electrolyte secondary battery according to Embodiment 2 of the present invention is porous on at least one surface of the separator for a nonaqueous electrolyte secondary battery (porous membrane) according to Embodiment 1 of the present invention. It is characterized in that the quality layers are laminated.

<Porous membrane>
The porous membrane in the present invention can be a base material for a separator for a non-aqueous electrolyte secondary battery or a laminated separator for a non-aqueous electrolyte secondary battery, which will be described later. It is possible to pass gas or liquid from one surface to the other surface.

“The main component is a polyolefin-based resin” means that the proportion of the polyolefin-based resin in the porous membrane is 50% by volume or more, preferably 90% by volume or more, more preferably 95% by volume of the entire porous membrane. That means that. The polyolefin resin preferably contains a high molecular weight component having a weight average molecular weight of 5 × 10 ⁵ to 15 × 10 ⁶ . In particular, when the polyolefin contains a high molecular weight component having a weight average molecular weight of 1,000,000 or more, the separator is a nonaqueous electrolyte secondary battery separator that is the porous membrane, and the laminate that includes the porous membrane. Since the intensity | strength of the laminated separator for water electrolyte secondary batteries improves, it is more preferable.

  The polyolefin-based resin that is the main component of the porous membrane is not particularly limited. For example, a monomer such as ethylene, propylene, 1-butene, 4-methyl-1-pentene, 1-hexene, which is a thermoplastic resin. Homopolymers (for example, polyethylene, polypropylene, polybutene) or copolymers (for example, ethylene-propylene copolymers) obtained by (co) polymerizing the above. Of these, polyethylene is more preferable because it can prevent (shut down) an excessive current from flowing at a lower temperature. Examples of the polyethylene include low density polyethylene, high density polyethylene, linear polyethylene (ethylene-α-olefin copolymer), ultrahigh molecular weight polyethylene having a weight average molecular weight of 1,000,000 or more, and of these, weight average molecular weight. Is more preferably an ultrahigh molecular weight polyethylene having 1 million or more.

  The thickness of the porous membrane is preferably 4 μm to 40 μm, more preferably 5 μm to 30 μm, and more preferably 6 to 15 μm, when the porous membrane alone becomes a separator for a non-aqueous electrolyte secondary battery. More preferably. Further, a porous membrane is used as a base material for a laminated separator for a non-aqueous electrolyte secondary battery, and a porous layer is laminated on one side or both sides of the porous membrane to obtain a laminated separator for a non-aqueous electrolyte secondary battery (laminated body). ), The thickness of the porous film may be appropriately determined in consideration of the thickness of the laminate, but is preferably 4 to 40 μm, more preferably 5 to 30 μm. preferable.

  When the thickness of the porous membrane is smaller than the above range, the non-aqueous electrolyte secondary battery including the non-aqueous electrolyte secondary battery separator and the non-aqueous electrolyte secondary battery laminated separator using the porous membrane. In a battery, an internal short circuit due to damage to the battery cannot be sufficiently prevented. In addition, the amount of electrolytic solution retained in the porous membrane is reduced. On the other hand, when the film thickness of the porous membrane is larger than the above range, lithium ions in the entire area of the nonaqueous electrolyte secondary battery separator and the nonaqueous electrolyte secondary battery laminated separator using the porous membrane are used. The transmission resistance increases. Therefore, in a non-aqueous electrolyte secondary battery including the separator, when the charge / discharge cycle is repeated, the positive electrode deteriorates, and the rate characteristics and cycle characteristics deteriorate. Further, since the distance between the positive electrode and the negative electrode is increased, the size of the non-aqueous electrolyte secondary battery is increased.

The basis weight per unit area of the porous membrane takes into account the strength, film thickness, weight, and handling properties of the nonaqueous electrolyte secondary battery separator or the nonaqueous electrolyte secondary battery multilayer separator provided with the porous membrane. And may be determined as appropriate. Specifically, in order to increase the weight energy density and volume energy density of the battery including the separator for non-aqueous electrolyte secondary battery or the laminated separator for non-aqueous electrolyte secondary battery, is preferably 4~20g / ^{m 2,} more preferably from 4~12g / ^{m 2,} further preferably 5 to 10 g / ^{m 2.}

Piercing strength for a basis weight per unit area of the porous film is preferably 26.0gf / g / ^{m 2} or more, 30.0gf / g / ^{m 2} or more is more preferable. When the piercing strength is too small, that is, less than 26.0 gf / g / m ² , the stacking and winding operation of the positive and negative electrodes and the separator in the battery assembly process, the pressing operation of the winding group, or the battery When pressure is applied from the outside, the separator may be pierced by the positive and negative electrode active material particles, and the positive and negative electrodes may be short-circuited.

  The air permeability of the porous membrane is preferably a Gurley value of 30 to 500 sec / 100 mL, and more preferably 50 to 300 sec / 100 mL. When the porous membrane has the above air permeability, the non-aqueous electrolyte secondary battery separator or the laminated separator for non-aqueous electrolyte secondary batteries provided with the porous membrane can obtain sufficient ion permeability. it can.

  The porosity of the porous membrane is 20 to 80% by volume so as to increase the amount of electrolyte retained and to obtain a function of reliably blocking (shutdown) the flow of excessive current at a lower temperature. Is preferable, and it is more preferable that it is 30 to 75 volume%.

  When the porosity of the porous film is less than 20% by volume, the resistance of the porous film increases. Moreover, when the porosity of a porous membrane exceeds 80 volume%, the mechanical strength of the said porous membrane will fall.

  In addition, the pore diameter of the porous membrane is such that the nonaqueous electrolyte secondary battery separator or the nonaqueous electrolyte secondary battery laminated separator provided with the porous membrane can obtain sufficient ion permeability. It is preferably 0.3 μm or less, more preferably 0.14 μm or less so that particles can be prevented from entering the positive electrode and the negative electrode.

The porous membrane of the present invention has a value represented by the following formula (1) in the range of 0.00 or more and 0.54 or less, preferably 0.00 or more and 0.50 or less, More preferably, it is 0.00 or more and 0.45 or less.
| 1-T / M | (1)
(In Formula (1), T represents a distance to a critical load in a scratch test under a constant load of 0.1 N in the TD direction, and M is a scratch under a constant load of 0.1 N in the MD direction. (Indicates the distance to the critical load in the test.)
In the porous membrane of the present invention, the value represented by the following formula (2) is preferably in the range of 0.00 or more and 0.54 or less, and is 0.00 or more and 0.50 or less. More preferably, it is 0.00 or more and 0.45 or less.
1-T / M (2)
(In Formula (2), T represents a distance to a critical load in a scratch test under a constant load of 0.1 N in TD, and M is a scratch test in a scratch test under a constant load of 0.1 N in MD. Represents the distance to the critical load.)
The values represented by the above formulas (1) and (2) are values indicating the anisotropy of the distance to the critical load in the scratch test. The closer the value is to zero, the greater the distance to the critical load. Is isotropic.

As shown in FIG. 1, the “scratch test” in the present invention is a state in which a constant load is applied to the indenter and the surface layer of the porous membrane to be measured is compressed and deformed (= indented state) in the thickness direction. Is a test for measuring the stress generated at a certain indenter moving distance when the porous membrane is moved in the horizontal direction. Specifically, the test is carried out by the following method:
(1) After cutting the porous film to be measured into 20 mm × 60 mm, the cut porous film and the glass preparation of 30 mm × 70 mm are covered on the entire surface of the preparation with a basis weight of about 1.5 g / m ^2. A test sample is prepared by laminating thinly and thinly using an Arabic Yamato aqueous liquid paste (manufactured by Yamato Co., Ltd.) diluted 5 times with water, and drying overnight at a temperature of 25 ° C. . In addition, at the time of the said bonding, care is taken so that a bubble may not enter between a porous membrane and glass preparations.
(2) The test sample prepared in step (1) is placed in a micro scratch test apparatus (manufactured by CSEM Instruments). The diamond indenter (conical shape with an apex angle of 120 ° and a tip radius of 0.2 mm) in the test apparatus is subjected to the test in a state where a vertical load of 0.1 N is applied on the test sample. The table in the apparatus is moved by a distance of 10 mm at a speed of 5 mm / min toward the TD of the porous membrane, during which stress (friction) generated between the diamond indenter and the test sample is generated. Force).
(3) A curve graph showing the relationship between the displacement of the stress measured in the step (2) and the movement distance of the table is created, and from the curve graph, as shown in FIG. Calculate the value and the distance to reach the critical load.
(4) The moving direction of the table is changed to MD, and the above steps (1) to (3) are repeated to calculate the critical load value and the distance to the critical load in MD.

  In addition, about the measurement conditions other than the above-mentioned conditions in the said scratch test, it implements on the conditions similar to the method as described in JISR3255.

  In the above scratch test, in the nonaqueous electrolyte secondary battery in which the porous membrane to be measured is incorporated as a separator or a member of the separator, the electrode mixture layer is expanded during charging / discharging of the battery (when charging: the negative electrode is expanded and discharged) : The interface between the surface layer of the separator (porous membrane) facing the expanding electrode and the surface of the separator (porous membrane) on the opposite side of the separator (porous membrane) and the electrode facing the surface layer due to the positive electrode expanding) This is a test that models and measures the influence mechanism on adhesion.

  Here, due to the expansion and contraction of the electrode mixture layer during charging and discharging, the surface layer on the surface side facing the expanding electrode of the separator (porous membrane) is expanded in the thickness direction by the expanded active material particles in contact with the surface layer. In addition to deformation (compression deformation), due to expansion of the composite material layer in the horizontal direction, shear stress (horizontal force on the separator electrode interface) is caused by particles deformed in the thickness direction of the separator (porous membrane). Furthermore, this shear stress is transmitted to the separator / electrode interface on the surface opposite to the expanded electrode via the resin inside the separator.

  Therefore, the distance to the critical load value calculated in the scratch test is (a) an index of the plastic deformation ease of the porous membrane (separator) surface layer, and (b) the shear stress on the surface opposite to the measurement surface. It becomes an indicator of transmissibility. The long distance to the critical load value means that (a ′) the surface layer portion is difficult to be plastically deformed in the porous film to be measured, and (b ′) the shear stress is transmitted to the surface opposite to the measurement surface. Low (stress is difficult to transmit).

  From the above, the value of the formula (1) in the porous membrane exceeding 0.54 indicates that there is a large anisotropy between TD and MD at the distance to the critical load value. Show. In a non-aqueous electrolyte secondary battery including such a porous film having large anisotropy as a separator or a member of the separator, plastic deformation of the separator (porous film) surface layer accompanying charge / discharge, and an expanded electrode The wrinkles and gaps at the interface between the separator and the electrode due to the difference in size between TD and MD in the transmission of surface stress to the opposite surface and the opposite surface of the surface are preferentially generated in a specific direction, As a result, the uniformity of the inter-electrode distance in the surface direction is reduced, so that the rate characteristic maintenance rate after the discharge cycle of the non-aqueous electrolyte secondary battery is lowered.

  Next, consider a nonaqueous electrolyte secondary battery in which the porous body is used as a separator or a member of the separator, which is an aspect of a laminated body composed of an electrode and a separator, in which the laminated body is wound. In the wound non-aqueous electrolyte secondary battery, the laminate is wound in a state where tension is applied to the separator in the MD direction. On the other hand, the internal stress is generated inward with respect to TD. Therefore, in the non-aqueous electrolyte secondary battery in which the laminate is wound, the distance to the MD critical load during actual operation is larger than the distance to the MD critical load calculated in the scratch test. The distance to the critical load in the TD direction is larger than the distance to the critical load of TD calculated in the scratch test. Therefore, even when the distance to the critical load of TD and MD is short, that is, when the isotropic property is high, specifically, a porous film having a value of formula (2) of −0.54 or more and less than 0.00 When used as a separator or separator member of a non-aqueous electrolyte secondary battery in which the laminate is wound, the distance to the critical load in the MD direction increases and the distance to the critical load in the TD direction decreases. Actually, the separator caused by the plastic deformation of the separator (porous membrane) surface layer to the TD and the difference in the transferability of the surface stress to the surface opposite to the surface facing the expanded electrode to the MD Wrinkles and gaps at the interelectrode interface occur preferentially in the TD, and the uniformity in the surface direction of the interelectrode distance decreases. On the other hand, even in the nonaqueous electrolyte secondary battery in which the laminate is wound, the anisotropy is large. Specifically, when the value of the formula (1) exceeds 0.54, the above reason For the same reason, the plastic deformation of the separator (porous membrane) surface in the direction where the distance to the critical load is large, and the transfer of surface stress to the surface opposite to the surface facing the expanded electrode The occurrence of wrinkles and gaps at the interface between the separator and the electrode due to the difference between TD and MD increases the distance to the critical load in a large direction. As a result, the rate characteristic maintenance rate after the discharge cycle of the nonaqueous electrolyte secondary battery is lowered. Therefore, the value of the formula (2) is 0.00 or more from the viewpoint that it can be suitably used for a non-aqueous electrolyte secondary battery in a form such as a non-aqueous electrolyte secondary battery in which the laminate is wound. 0.54 or less is preferable.

In addition, it is thought that the distance to the critical load in the TD direction and the MD direction is strongly influenced by the following structure factor of the porous film.
(I) Orientation state of resin to MD in porous membrane (ii) Orientation state of resin to TD in porous membrane (iii) Contact state of resin oriented in MD direction and TD direction in thickness direction of porous membrane Therefore, as a method for controlling the values of the formulas (1) and (2), the structures of the above (i) to (iii) are adjusted by adjusting the following production conditions in the porous membrane production method described later. A method for controlling the factor is mentioned.
(1) Rolling roll peripheral speed [m / min]
(2) Ratio of stretching temperature / stretching ratio [° C./%]
Specifically, in the range where the peripheral speed of the rolling roll, the stretching temperature for stretching, and the stretching ratio do not hinder the production of the porous membrane, the circumferential speed of the rolling roll is satisfied so as to satisfy the relationship of the following formula (3). By adjusting the speed and the ratio of stretching temperature / stretching ratio, the values of the formulas (1) and (2) can be controlled in the range of 0.00 to 0.54 as a result. .
Y ≧ −2.3 × X + 22.2 (3)
(In formula (3), X represents the peripheral speed of the rolling roll, and Y represents the ratio of the stretching temperature / stretching ratio of TD stretching.)
On the other hand, when set in a range that deviates from the relationship of the above formula (3), the orientation of the resin to the MD or TD of the porous film and / or the orientation to either MD or TD The connectivity of the obtained resin in the thickness direction of the porous membrane is promoted, the anisotropy of the porous membrane represented by the formula (1) is increased, and the value of the formula (1) is set to 0.00 or more and 0.00. It cannot be controlled within the range of 54 or less. For example, when the peripheral speed of the rolling roll is adjusted to 2.5 m / min and the ratio of stretching temperature / stretching ratio is adjusted to less than 16.5 ° C./%, the resin orientation to the TD of the porous film and the connection in the thickness direction thereof By increasing the property, the distance to the critical load in TD is reduced, and as a result, the anisotropy represented by the formula (1) is 0.54 or more.

  In addition, the stretching temperature is preferably 90 ° C. or higher and 120 ° C. or lower, and more preferably 100 ° C. or higher and 110 ° C. or lower. In addition, the draw ratio is preferably 600% or more and 800% or less, and more preferably 620% or more and 700% or less.

  In addition, when a porous layer is formed on a porous membrane to produce a laminated separator for a non-aqueous electrolyte secondary battery, before forming the porous layer, that is, a coating solution described later is applied. It is more preferable to perform a hydrophilic treatment before the work. By applying a hydrophilic treatment to the porous film, the coating property of the coating liquid is further improved, and therefore a more uniform porous layer can be formed. This hydrophilization treatment is effective when the proportion of water in the solvent (dispersion medium) contained in the coating liquid is high. Specific examples of the hydrophilic treatment include known treatments such as chemical treatment with acid or alkali, corona treatment, plasma treatment and the like. Among the above hydrophilization treatments, the porous membrane can be hydrophilized in a relatively short time, and the hydrophilization is limited only to the vicinity of the surface of the porous membrane, so that the inside of the porous membrane does not change, Corona treatment is more preferred.

<Method for producing porous membrane>
The method for producing the porous membrane is not particularly limited, and examples thereof include a method in which a plasticizer is added to a resin such as polyolefin to form a film (film-like), and then the plasticizer is removed with an appropriate solvent. .

Specifically, for example, when manufacturing a porous membrane using a polyolefin resin containing ultrahigh molecular weight polyethylene and a low molecular weight polyolefin having a weight average molecular weight of 10,000 or less, from the viewpoint of manufacturing cost, It is preferable to produce the porous membrane by the method shown.
(1) Kneading 100 parts by weight of ultrahigh molecular weight polyethylene, 5 to 200 parts by weight of a low molecular weight polyolefin having a weight average molecular weight of 10,000 or less, and 100 to 400 parts by weight of a pore forming agent such as calcium carbonate or a plasticizer. Obtaining a polyolefin resin composition;
(2) forming a rolled sheet by rolling the polyolefin resin composition;
Then
(3) A step of removing the hole forming agent from the rolled sheet obtained in step (2),
(4) A step of stretching the sheet from which the hole forming agent has been removed in step (3),
(5) A step of heat-fixing the sheet stretched in step (4) at a heat setting temperature of 100 ° C. or higher and 150 ° C. or lower to obtain a porous film.
Or
(3 ′) a step of stretching the rolled sheet obtained in step (2),
(4 ′) a step of removing the hole forming agent from the sheet stretched in the step (3 ′),
(5 ′) A step of heat-fixing the sheet obtained in step (4 ′) at a heat setting temperature of 100 ° C. or higher and 150 ° C. or lower to obtain a porous film.

  Here, by adjusting the peripheral speed of the rolling roll used for the rolling treatment in the step (2) and / or the ratio of the stretching temperature / stretching ratio of the stretching in the step (4) and the step (3 ′), A porous membrane satisfying the formulas (1) and (2) can be produced.

Specifically, it is preferable to adjust the peripheral speed of the rolling roll and the ratio of stretching temperature / stretching ratio so as to satisfy the relationship of the following formula (3).
Y ≧ −2.3 × X + 22.2 (3)
(In formula (3), X represents the peripheral speed of the rolling roll, and Y represents the ratio of the stretching temperature / stretching ratio of TD stretching.)
Furthermore, the porous film which satisfies Formula (1) and Formula (2) can be manufactured also by repeating extending | stretching and heat setting operation again after cooling the stretched film after heat setting. Specifically, a method of performing additional stretching in the MD direction and the TD direction is exemplified, and the MD direction is preferable as the direction of the additional stretching.

  In addition, if necessary, a porous film satisfying the expressions (1) and (2) can be manufactured by appropriately combining other conditions such as the composition of the porous film and the heat setting temperature.

  Moreover, you may provide well-known porous layers, such as an adhesion layer, a heat-resistant layer, and a protective layer, on a porous membrane. In this specification, a separator provided with a separator for a non-aqueous electrolyte secondary battery and a porous layer is referred to as a laminated separator for a non-aqueous electrolyte secondary battery (hereinafter sometimes referred to as a laminated separator). When a porous layer is formed on the porous membrane to produce a laminated separator for a non-aqueous electrolyte secondary battery, the coating liquid described later is applied before forming the porous layer. More preferably, the porous membrane is subjected to a hydrophilic treatment before. By applying a hydrophilic treatment to the porous film, the coating property of the coating liquid is further improved, and therefore a more uniform porous layer can be formed. This hydrophilization treatment is effective when the proportion of water in the solvent (dispersion medium) contained in the coating liquid is high. Specific examples of the hydrophilic treatment include known treatments such as chemical treatment with acid or alkali, corona treatment, plasma treatment and the like. Among the above hydrophilization treatments, the porous membrane can be hydrophilized in a relatively short time, and the hydrophilization is limited only to the vicinity of the surface of the porous membrane, so that the inside of the porous membrane does not change, Corona treatment is more preferred.

<Porous layer>
The porous layer according to the present invention is usually a resin layer containing a resin and may contain fine particles. The porous layer according to the present invention is preferably a heat-resistant layer or an adhesive layer laminated on one side or both sides of the porous membrane. The resin constituting the porous layer is preferably insoluble in the battery electrolyte and electrochemically stable in the battery usage range. When a porous layer is laminated on one side of the porous membrane, the porous layer is preferably laminated on the surface of the porous membrane facing the positive electrode when a non-aqueous electrolyte secondary battery is used. More preferably, it is laminated on the surface in contact with the positive electrode.

  Specific examples of the resin include polyolefins such as polyethylene, polypropylene, polybutene, and ethylene-propylene copolymer; homopolymers of vinylidene fluoride (polyvinylidene fluoride) and copolymers of vinylidene fluoride (for example, Vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene copolymer), tetrafluoroethylene copolymer (for example, ethylene-tetrafluoroethylene copolymer), etc. Fluororesin; Fluororesin having a glass transition temperature of 23 ° C. or less among the fluorinated resins; aromatic polyamide; wholly aromatic polyamide (aramid resin); styrene-butadiene copolymer and its hydride, methacrylate ester Polymer, acrylonitrile -Rubbers such as acrylic acid ester copolymer, styrene-acrylic acid ester copolymer, ethylene propylene rubber, polyvinyl acetate; polyphenylene ether, polysulfone, polyethersulfone, polyphenylene sulfide, polyetherimide, polyamideimide, polyether Resins having a melting point or glass transition temperature of 180 ° C. or higher such as amide and polyester; water-soluble polymers such as polyvinyl alcohol, polyethylene glycol, cellulose ether, sodium alginate, polyacrylic acid, polyacrylamide, and polymethacrylic acid.

  Moreover, a water-insoluble polymer can also be used suitably as resin contained in the porous layer which concerns on this invention. In other words, when the porous layer according to the present invention is produced, an emulsion or a dispersion in which a water-insoluble polymer (for example, acrylate resin) is dispersed in an aqueous solvent is used, and the water-insoluble as the resin. It is also preferred to produce a porous layer according to the invention comprising a polymer.

  Here, the water-insoluble polymer is a polymer that does not dissolve in the aqueous solvent but becomes particles and is dispersed in the aqueous solvent. Although the definition of the water-insoluble polymer is not clear, for example, according to International Publication No. 2013/031690, “the polymer is water-insoluble” means that 0.5 g of the polymer is added to 100 g of water at 25 ° C. It is defined as that when dissolved, the insoluble content becomes 90% by weight or more. On the other hand, “the polymer is water-soluble” is defined to mean that when 0.5 g of the polymer is dissolved in 100 g of water at 25 ° C., the insoluble content is less than 0.5% by weight. ing. The shape of the water-insoluble polymer particles is not particularly limited, but is preferably spherical.

  The water-insoluble polymer is produced, for example, by polymerizing a monomer composition containing a monomer described later in an aqueous solvent to form polymer particles.

  Examples of the water-insoluble polymer monomer include styrene, vinyl ketone, acrylonitrile, methyl methacrylate, ethyl methacrylate, glycidyl methacrylate, glycidyl acrylate, methyl acrylate, ethyl acrylate, and butyl acrylate.

  In addition to the monomer homopolymer, the polymer may include a copolymer of two or more monomers. Examples of the polymer include polyvinylidene fluoride and vinylidene fluoride copolymers (for example, vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene copolymer), tetrafluoroethylene. Fluorine-containing resin of a copolymer (for example, ethylene-tetrafluoroethylene copolymer); melamine resin; urea resin; polyethylene; polypropylene; polymethyl acrylate, polymethyl methacrylate, polybutyl acrylate;

  The aqueous solvent is not particularly limited as long as it contains water as a main component and can disperse the water-insoluble polymer particles. Methanol, ethanol, isopropyl alcohol, acetone, tetrahydrofuran, which can be mixed with water at an arbitrary ratio, An organic solvent such as acetonitrile and N-methylpyrrolidone may be contained in any amount, and a surfactant such as sodium dodecylbenzenesulfonate, a dispersant such as polyacrylic acid, sodium salt of carboxymethylcellulose, etc. may be added. May be. When an additive such as the solvent or surfactant is used, it can be used alone or in combination of two or more, and the weight ratio of the organic solvent to water is 0.1 to 99% by weight, preferably It is 0.5 to 80 weight%, More preferably, it is 1 to 50 weight%.

  In addition, the resin contained in the porous layer according to the present invention may be one type or a mixture of two or more types of resins.

Specific examples of the aromatic polyamide include poly (paraphenylene terephthalamide), poly (metaphenylene isophthalamide), poly (parabenzamide), poly (metabenzamide), and poly (4,4 ′). -Benzanilide terephthalamide), poly (paraphenylene-4,4'-biphenylenedicarboxylic acid amide), poly (metaphenylene-4,4'-biphenylenedicarboxylic acid amide), poly (paraphenylene-2,6-naphthalenedicarboxylic acid) Acid amide), poly (metaphenylene-2,6-naphthalenedicarboxylic acid amide), poly (2-chloroparaphenylene terephthalamide), paraphenylene terephthalamide / 2,6-dichloroparaphenylene terephthalamide copolymer, metaphenylene Terephthalamide / 2,6 Dichloro-para-phenylene terephthalamide copolymer and the like. Of these, poly (paraphenylene terephthalamide) is more preferable.
Among the above resins, polyolefin, fluorine-containing resin, aromatic polyamide, water-soluble polymer, and particulate water-insoluble polymer dispersed in an aqueous solvent are more preferable. In particular, when the porous layer is arranged facing the positive electrode, various performances such as rate characteristics and resistance characteristics (liquid resistance) of the non-aqueous electrolyte secondary battery are maintained due to acid degradation during battery operation. Fluorine-containing resins and fluorine-containing rubbers are more preferable because they are easy, and vinylidene fluoride and at least one monomer selected from the group consisting of hexafluoropropylene, tetrafluoroethylene, trifluoroethylene, trichloroethylene, and vinyl fluoride, etc. A copolymer (that is, vinylidene fluoride-hexafluoropropylene copolymer, etc.) and a homopolymer of vinylidene fluoride (that is, polyvinylidene fluoride) are particularly preferable. The water-soluble polymer and the particulate water-insoluble polymer dispersed in an aqueous solvent are more preferable from the viewpoint of process and environmental load because water can be used as a solvent when forming the porous layer. The water-soluble polymer is more preferably cellulose ether or sodium alginate, particularly preferably cellulose ether.

  Specific examples of the cellulose ether include carboxymethyl cellulose (CMC), hydroxyethyl cellulose (HEC), carboxyethyl cellulose, methyl cellulose, ethyl cellulose, cyanethyl cellulose, oxyethyl cellulose, etc. CMC and HEC which are excellent in chemical stability are more preferable, and CMC is particularly preferable.

  Further, the particulate water-insoluble polymer dispersed in the aqueous solvent is methacrylic acid from the viewpoint of adhesiveness between the fine particles (for example, between inorganic fillers) when the porous layer of the present invention contains fine particles. Homopolymers of acrylate monomers such as methyl, ethyl methacrylate, glycidyl methacrylate, glycidyl acrylate, methyl acrylate, ethyl acrylate, and butyl acrylate, or copolymers of two or more types of monomers are preferred.

  The fine particles in the present specification are organic fine particles or inorganic fine particles generally called a filler. Therefore, the resin has a function as a binder resin that binds the fine particles to each other and the fine particles and the porous film. The fine particles are preferably insulating fine particles.

  Specific examples of the organic fine particles contained in the porous layer in the present invention include monomers such as styrene, vinyl ketone, acrylonitrile, methyl methacrylate, ethyl methacrylate, glycidyl methacrylate, glycidyl acrylate, and methyl acrylate. Homopolymer or two or more types of copolymers; fluorinated resins such as polytetrafluoroethylene, tetrafluoroethylene-6-fluoropropylene copolymer, tetrafluoroethylene-ethylene copolymer, polyvinylidene fluoride; melamine Resin; urea resin; polyethylene; polypropylene; polyacrylic acid, polymethacrylic acid; These organic fine particles are insulating fine particles.

  Specifically, the inorganic fine particles contained in the porous layer in the present invention include, for example, calcium carbonate, talc, clay, kaolin, silica, hydrotalcite, diatomaceous earth, magnesium carbonate, barium carbonate, calcium sulfate, magnesium sulfate, Examples include fillers made of inorganic substances such as barium sulfate, aluminum hydroxide, boehmite, magnesium hydroxide, calcium oxide, magnesium oxide, titanium oxide, titanium nitride, alumina (aluminum oxide), aluminum nitride, mica, zeolite, and glass. These inorganic fine particles are insulating fine particles. Only one type of fine particles may be used, or two or more types may be used in combination.

  Among the above fine particles, fine particles made of an inorganic substance are suitable, and fine particles made of an inorganic oxide such as silica, calcium oxide, magnesium oxide, titanium oxide, alumina, mica, zeolite, aluminum hydroxide, boehmite are more preferable, silica, At least one fine particle selected from the group consisting of magnesium oxide, titanium oxide, aluminum hydroxide, boehmite and alumina is more preferred, and alumina is particularly preferred. Alumina has many crystal forms such as α-alumina, β-alumina, γ-alumina, and θ-alumina, and any of them can be suitably used. Among these, α-alumina is most preferable because of its particularly high thermal stability and chemical stability.

  The shape of the fine particles varies depending on the production method of the organic or inorganic material as a raw material, the dispersion conditions of the fine particles when producing a coating liquid for forming a porous layer, and the like, spherical, oval, short, The shape may be any shape such as a shape or an indefinite shape having no specific shape.

  In the case where the porous layer contains fine particles, the content of the fine particles is preferably 1 to 99% by volume, more preferably 5 to 95% by volume of the porous layer. By setting the content of the fine particles in the above range, voids formed by the contact between the fine particles are less likely to be blocked by a resin or the like, and sufficient ion permeability can be obtained, and per unit area. The basis weight can be set to an appropriate value.

  The fine particles may be used in combination of two or more different particle diameters and specific surface areas.

  The content of the fine particles contained in the porous layer is preferably 1 to 99% by volume, more preferably 5 to 95% by volume of the porous layer. By setting the content of the fine particles in the above range, voids formed by the contact between the fine particles are less likely to be blocked by a resin or the like, and sufficient ion permeability can be obtained, and per unit area. The basis weight can be set to an appropriate value.

  The film thickness of the porous layer according to the present invention may be appropriately determined in consideration of the film thickness of the laminate that is a laminated separator for a non-aqueous electrolyte secondary battery. In the case of forming a laminate by laminating a porous layer on one side or both sides of a membrane, it is preferably 0.5 to 15 μm (per one side), more preferably 2 to 10 μm (per one side). preferable.

  When the thickness of the porous layer is less than 1 μm, an internal short circuit due to battery breakage or the like cannot be sufficiently prevented when the laminate is used as a laminate separator for a nonaqueous electrolyte secondary battery. In addition, the amount of electrolytic solution retained in the porous layer decreases. On the other hand, if the total thickness of the porous layer exceeds 30 μm, when the laminate is used as a laminated separator for a non-aqueous electrolyte secondary battery, the lithium ion permeation resistance increases across the separator. When the cycle is repeated, the positive electrode deteriorates, and the rate characteristics and cycle characteristics deteriorate. In addition, since the distance between the positive electrode and the negative electrode is increased, the nonaqueous electrolyte secondary battery is increased in size.

  In the following explanation regarding the physical properties of the porous layer, when the porous layer is laminated on both sides of the porous membrane, the surface of the porous membrane facing the positive electrode when a non-aqueous electrolyte secondary battery is formed is used. It refers to at least the physical properties of the laminated porous layer.

The basis weight per unit area (per side) of the porous layer may be appropriately determined in consideration of the strength, film thickness, weight, and handling properties of the laminate, but the laminate is used for a non-aqueous electrolyte secondary battery. to be able to increase the weight energy density and volume energy density of the battery in the case of using a laminated separator, usually, it is preferably from 1 to 20 g / m ^2, a 4~10g / m ² More preferred. When the basis weight of the porous layer exceeds the above range, the non-aqueous electrolyte secondary battery becomes heavy when the laminate is used as a laminated separator for non-aqueous electrolyte secondary batteries.

The volume of the porous layer constituents contained per square meter porous layer (per one side) is preferably 0.5～20Cm ^3, more preferably 1 to 10 cm ^3,. 2 to More preferably, it is 7 cm ³ . That is, component volume of the porous layer having a basis weight (per one side) is preferably 0.5~20cm ³ / ^{m 2,} more preferably ^{1~10cm 3 / m 2, 2~7cm 3} / m ² is more preferable. When the volume per unit volume of the porous layer is less than 0.5 cm ³ / m ² , the internal short circuit due to battery damage or the like is sufficiently prevented when the laminate is used as a laminate separator for a non-aqueous electrolyte secondary battery. It cannot be prevented. Moreover, when the volume per unit area of the porous layer exceeds 20 cm ³ / m ² , when the laminate is used as a laminated separator for a non-aqueous electrolyte secondary battery, the lithium ion permeation resistance in the entire separator is reduced. Therefore, when the cycle is repeated, the positive electrode deteriorates, and the rate characteristics and cycle characteristics deteriorate.

  The porosity of the porous layer is preferably 20 to 90% by volume, and more preferably 30 to 80% by volume so that sufficient ion permeability can be obtained. The pore diameter of the porous layer is 3 μm so that the porous layer and the laminated separator for a non-aqueous electrolyte secondary battery including the porous layer can obtain sufficient ion permeability. Or less, more preferably 1 μm or less.

<Laminated body>
The laminated body which is a laminated separator for non-aqueous electrolyte secondary batteries of the present invention has a configuration in which the above porous layer is laminated on one side or both sides of the above porous membrane.

  The thickness of the laminate in the present invention is preferably 5.5 μm to 45 μm, and more preferably 6 μm to 25 μm.

  The air permeability of the laminate in the present invention is preferably 30 to 1000 sec / 100 mL as a Gurley value, and more preferably 50 to 800 sec / 100 mL. When the laminate has the above air permeability, sufficient ion permeability can be obtained when the laminate is used as a laminate separator for a non-aqueous electrolyte secondary battery. When the air permeability exceeds the above range, it means that the laminated structure is rough because the porosity of the laminated body is high, and as a result, the strength of the laminated body is reduced, and the shape at a high temperature is particularly high. Stability may be insufficient. On the other hand, if the air permeability is less than the above range, sufficient ion permeability cannot be obtained when used as a laminated separator for a non-aqueous electrolyte secondary battery, and the non-aqueous electrolyte secondary battery Battery characteristics may be degraded.

In addition to the above porous film and porous layer, the laminated body in the present invention does not impair the object of the present invention with a known porous film such as a heat-resistant layer, an adhesive layer, or a protective layer, if necessary. It may be included in the range.
<Method for producing porous layer and laminate>
As a manufacturing method of the porous layer and laminated body in this invention, the method of depositing a porous layer by apply | coating the coating liquid mentioned later to the surface of the said porous membrane, and drying is mentioned, for example.

  The coating liquid used in the method for producing a porous layer in the present invention usually dissolves the resin contained in the porous layer in the present invention in a solvent and disperses the fine particles contained in the porous layer in the present invention. Can be prepared.

  The solvent (dispersion medium) is not particularly limited as long as it does not adversely affect the porous membrane, can dissolve the resin uniformly and stably, and can uniformly and stably disperse the fine particles. Specific examples of the solvent (dispersion medium) include water; lower alcohols such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, and t-butyl alcohol; acetone, toluene, xylene, hexane, N -Methylpyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide and the like. The solvent (dispersion medium) may be used alone or in combination of two or more.

  The coating liquid may be formed by any method as long as the conditions such as the resin solid content (resin concentration) and the amount of fine particles necessary for obtaining a desired porous layer can be satisfied. Specific examples of the method for forming the coating liquid include a mechanical stirring method, an ultrasonic dispersion method, a high-pressure dispersion method, and a media dispersion method. Further, for example, fine particles may be dispersed in a solvent (dispersion medium) by using a conventionally known disperser such as a three-one motor, a homogenizer, a media type disperser, or a pressure disperser. Furthermore, a solution obtained by dissolving or swelling a resin or an emulsion of a resin is supplied into a wet pulverization apparatus at the time of wet pulverization to obtain fine particles having a desired average particle size, and is applied simultaneously with the wet pulverization of the fine particles A liquid can also be prepared. That is, the wet pulverization of the fine particles and the preparation of the coating liquid may be performed simultaneously in one step. In addition, the coating liquid may contain additives such as a dispersant, a plasticizer, a surfactant, and a pH adjuster as components other than the resin and fine particles as long as the object of the present invention is not impaired. . In addition, the addition amount of an additive should just be a range which does not impair the objective of this invention.

  The method for applying the coating liquid to the porous film, that is, the method for forming the porous layer on the surface of the porous film that has been subjected to hydrophilic treatment as necessary is not particularly limited. In the case of laminating a porous layer on both sides of the porous membrane, a sequential laminating method in which a porous layer is formed on one surface of the porous membrane and then a porous layer is formed on the other surface, or a porous membrane A simultaneous lamination method in which a porous layer is simultaneously formed on both surfaces of the substrate can be performed. As a method for forming a porous layer, that is, a method for producing a laminate, for example, a method in which a coating liquid is directly applied to the surface of a porous film and then a solvent (dispersion medium) is removed; A method in which a porous layer is formed by removing the solvent (dispersion medium) after applying to the body, and then pressing the porous layer and the porous membrane and then peeling the support; A method of removing the solvent (dispersion medium) after peeling the support, and then immersing the porous membrane in the coating solution and performing dip coating And a method of removing the solvent (dispersion medium). The thickness of the porous layer is the thickness of the coating film in the wet state (wet) after coating, the weight ratio between the resin and fine particles, and the solid content concentration of the coating liquid (the sum of the resin concentration and fine particle concentration) It can be controlled by adjusting etc. In addition, as a support body, a resin film, a metal belt, a drum, etc. can be used, for example.

  The method for applying the coating liquid to the porous membrane or the support is not particularly limited as long as it is a method capable of realizing the necessary weight per unit area and coating area. As a coating method of the coating liquid, conventionally known methods can be employed. Specifically, for example, a gravure coater method, a small diameter gravure coater method, a reverse roll coater method, a transfer roll coater method, a kiss coater method, a dip coater method, Examples include a coater method, a knife coater method, an air doctor blade coater method, a blade coater method, a rod coater method, a squeeze coater method, a cast coater method, a bar coater method, a die coater method, a screen printing method, and a spray coating method.

  As a method for removing the solvent (dispersion medium), a drying method is generally used. Examples of the drying method include natural drying, air drying, heat drying, and drying under reduced pressure. Any method may be used as long as the solvent (dispersion medium) can be sufficiently removed. Further, the solvent (dispersion medium) contained in the coating liquid may be replaced with another solvent before drying. As a method for removing the solvent (dispersion medium) after replacing it with another solvent, for example, it is possible to dissolve in the solvent (dispersion medium) contained in the coating liquid and not dissolve the resin contained in the coating liquid. A porous film or support on which a coating liquid is applied and a coating film is formed by immersing the solvent X in the solvent X to form a coating film on the porous film or the support. A method of evaporating the solvent X after replacing the solvent (dispersion medium) therein with the solvent X can be mentioned. This method can efficiently remove the solvent (dispersion medium) from the coating solution. When heating is performed when the solvent (dispersion medium) or the solvent X is removed from the coating film of the coating liquid formed on the porous film or the support, the pores of the porous film contract and become transparent. In order to avoid a decrease in the air temperature, it is desirable to carry out at a temperature at which the air permeability of the porous membrane does not decrease, specifically 10 to 120 ° C., more preferably 20 to 80 ° C.

  As a method for removing the solvent (dispersion medium), it is particularly preferable to form the porous layer by applying the coating liquid to the substrate and then drying the coating liquid. According to the above configuration, it is possible to realize a porous layer having a smaller variation rate of the porosity of the porous layer and less wrinkles.

  A normal drying apparatus can be used for the drying.

[Embodiment 3: Nonaqueous electrolyte secondary battery member, Embodiment 4: Nonaqueous electrolyte secondary battery]
A member for a non-aqueous electrolyte secondary battery according to Embodiment 3 of the present invention is a positive electrode, a separator for a non-aqueous electrolyte secondary battery according to Embodiment 1 of the present invention, or a non-aqueous liquid according to Embodiment 2 of the present invention. The laminated separator for electrolyte secondary batteries and the negative electrode are arranged in this order. In addition, the nonaqueous electrolyte secondary battery according to Embodiment 4 of the present invention is a nonaqueous electrolyte secondary battery separator according to Embodiment 1 of the present invention, or the nonaqueous electrolyte solution according to Embodiment 2 of the present invention. It includes a laminated separator for a secondary battery, and preferably includes a nonaqueous electrolyte secondary battery member according to Embodiment 3 of the present invention. In addition, the non-aqueous electrolyte secondary battery according to Embodiment 4 of the present invention additionally includes a non-aqueous electrolyte.

[Non-aqueous electrolyte]
The non-aqueous electrolyte in the present invention is a non-aqueous electrolyte generally used for a non-aqueous electrolyte secondary battery and is not particularly limited. For example, a non-aqueous electrolyte obtained by dissolving a lithium salt in an organic solvent is used. Can be used. Examples of the lithium salt include LiClO ₄ , LiPF ₆ , LiAsF ₆ , LiSbF ₆ , LiBF ₄ , LiCF ₃ SO ₃ , LiN (CF ₃ SO ₂ ) ₂ , LiC (CF ₃ SO ₂ ) ₃ , Li ₂ B ₁₀ Cl ₁₀ , lower aliphatic carboxylic acid lithium salt, LiAlCl _{4 and the} like. The lithium salt may be used alone or in combination of two or more. Among the lithium salts, at least one selected from the group consisting of LiPF ₆ , LiAsF ₆ , LiSbF ₆ , LiBF ₄ , LiCF ₃ SO ₃ , LiN (CF ₃ SO ₂ ) ₂ , and LiC (CF ₃ SO ₂ ) _3. More preferred are fluorine-containing lithium salts.

  Specific examples of the organic solvent constituting the non-aqueous electrolyte in the present invention include, for example, ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, 4-trifluoromethyl-1,3-dioxolane- Carbonates such as 2-one and 1,2-di (methoxycarbonyloxy) ethane; 1,2-dimethoxyethane, 1,3-dimethoxypropane, pentafluoropropyl methyl ether, 2,2,3,3-tetrafluoro Ethers such as propyldifluoromethyl ether, tetrahydrofuran and 2-methyltetrahydrofuran; esters such as methyl formate, methyl acetate and γ-butyrolactone; nitriles such as acetonitrile and butyronitrile; N, N-dimethylformamide, N, Amides such as dimethylacetamide; carbamates such as 3-methyl-2-oxazolidone; sulfur-containing compounds such as sulfolane, dimethyl sulfoxide and 1,3-propane sultone; and a fluorine group introduced into the organic solvent. And the like. Only one kind of the organic solvent may be used, or two or more kinds may be used in combination. Among the organic solvents, carbonates are more preferable, and a mixed solvent of cyclic carbonate and acyclic carbonate, or a mixed solvent of cyclic carbonate and ethers is more preferable. As a mixed solvent of cyclic carbonate and non-cyclic carbonate, ethylene carbonate has a wide operating temperature range and is difficult to decompose even when a graphite material such as natural graphite or artificial graphite is used as the negative electrode active material. More preferred is a mixed solvent containing dimethyl carbonate and ethyl methyl carbonate.

[Positive electrode]
As the positive electrode, a sheet-like positive electrode in which a positive electrode mixture containing a positive electrode active material, a conductive material, and a binder is usually supported on a positive electrode current collector is used.

Examples of the positive electrode active material include materials that can be doped / undoped with lithium ions. Specific examples of the material include lithium composite oxides containing at least one transition metal such as V, Mn, Fe, Co, and Ni. Among the lithium composite oxides, since the average discharge potential is high, lithium composite oxides having an α-NaFeO ₂ type structure such as lithium nickelate and lithium cobaltate, and lithium composites having a spinel type structure such as lithium manganese spinel Oxides are more preferred. The lithium composite oxide may contain various metal elements, and composite lithium nickelate is more preferable.

  Furthermore, the number of moles of at least one metal element selected from the group consisting of Ti, Zr, Ce, Y, V, Cr, Mn, Fe, Co, Cu, Ag, Mg, Al, Ga, In, and Sn When using the composite lithium nickelate containing the metal element so that the ratio of the at least one metal element is 0.1 to 20 mol% with respect to the sum of the number of moles of Ni in the lithium nickelate, It is even more preferable since it is excellent in cycle characteristics in use at a high capacity. Among them, an active material containing Al or Mn and having a Ni ratio of 85% or more, more preferably 90% or more is used in a high capacity of a non-aqueous electrolyte secondary battery including a positive electrode containing the active material. Since it is excellent in cycling characteristics, it is especially preferable.

  Examples of the conductive material include carbonaceous materials such as natural graphite, artificial graphite, cokes, carbon black, pyrolytic carbons, carbon fibers, and fired organic polymer compounds. Only one type of the conductive material may be used. For example, two or more types may be used in combination, such as a mixture of artificial graphite and carbon black.

  Examples of the binder include polyvinylidene fluoride, vinylidene fluoride copolymer, polytetrafluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymer, and tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer. , Ethylene-tetrafluoroethylene copolymer, vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene copolymer, thermoplastic polyimide, polyethylene, polypropylene, etc. Examples thereof include resins, acrylic resins, and styrene butadiene rubber. The binder also has a function as a thickener.

  As a method for obtaining the positive electrode mixture, for example, a method of obtaining a positive electrode mixture by pressurizing a positive electrode active material, a conductive material and a binder on a positive electrode current collector; a positive electrode active material, a conductive material using an appropriate organic solvent And a method of obtaining a positive electrode mixture by pasting a material and a binder.

  Examples of the positive electrode current collector include conductors such as Al, Ni, and stainless steel, and Al is more preferable because it is easily processed into a thin film and is inexpensive.

  As a method for producing a sheet-like positive electrode, that is, a method of loading a positive electrode mixture on a positive electrode current collector, for example, a positive electrode active material, a conductive material, and a binder as a positive electrode mixture are added on the positive electrode current collector. Method of pressure molding: After a positive electrode active material, a conductive material and a binder are pasted using an appropriate organic solvent to obtain a positive electrode mixture, the positive electrode mixture is applied to the positive electrode current collector and dried. And a method of pressurizing the obtained sheet-like positive electrode mixture and fixing it to the positive electrode current collector.

[Negative electrode]
As the negative electrode, a sheet-like negative electrode in which a negative electrode mixture containing a negative electrode active material is usually supported on a negative electrode current collector is used. The sheet-like negative electrode preferably contains the conductive material and the binder.

Examples of the negative electrode active material include materials that can be doped / undoped with lithium ions, lithium metal, and lithium alloys. Specific examples of the material include carbonaceous materials such as natural graphite, artificial graphite, cokes, carbon black, pyrolytic carbons, carbon fibers, and fired organic polymer compounds; Lithium ion doping and dedoping oxides, chalcogen compounds such as sulfides; aluminum (Al), lead (Pb), tin (Sn), bismuth (Bi), silicon (Si), etc. alloyed with alkali metals Cubic intermetallic compounds (AlSb, Mg ₂ Si, NiSi ₂ ), lithium nitrogen compounds (Li _{3 -x} M _x N (M: transition metal)), etc., which can insert an alkali metal between the lattices of Can be mentioned. Among the negative electrode active materials, the potential flatness is high, and since the average discharge potential is low, a large energy density can be obtained when combined with the positive electrode. Therefore, the main component is a graphite material such as natural graphite or artificial graphite. A carbonaceous material is more preferable. Moreover, the mixture of graphite and silicon may be sufficient, The negative electrode active material whose ratio of Si with respect to the carbon (C) which comprises the graphite is 5% or more is preferable, and the negative electrode active material which is 10% or more is more preferable.

  As a method for obtaining the negative electrode mixture, for example, a method in which the negative electrode active material is pressurized on the negative electrode current collector to obtain the negative electrode mixture; the negative electrode active material is pasted into a paste using an appropriate organic solvent. And the like.

  Examples of the negative electrode current collector include Cu, Ni, stainless steel, and the like. In particular, in a lithium ion secondary battery, it is difficult to form an alloy with lithium, and Cu is more preferable because it is easy to process into a thin film.

  As a method for producing a sheet-like negative electrode, that is, a method of supporting the negative electrode mixture on the negative electrode current collector, for example, a method in which a negative electrode active material to be the negative electrode mixture is pressure-molded on the negative electrode current collector; After the negative electrode active material is made into a paste using an organic solvent to obtain a negative electrode mixture, the negative electrode mixture is applied to the negative electrode current collector and dried to press the sheet-like negative electrode mixture. And a method of fixing to the negative electrode current collector. The paste preferably contains the conductive material and the binder.

  As a manufacturing method of the member for nonaqueous electrolyte secondary batteries of the present invention, for example, a method of arranging the above-mentioned positive electrode, the above-mentioned porous membrane, or the above-mentioned layered product, and a negative electrode in this order is mentioned. Moreover, as a manufacturing method of the nonaqueous electrolyte secondary battery of this invention, after forming the member for nonaqueous electrolyte secondary batteries by the said method, it becomes a housing | casing of a nonaqueous electrolyte secondary battery, for example. The non-aqueous electrolyte secondary battery according to the present invention is sealed by putting the non-aqueous electrolyte secondary battery member into a container, and then filling the container with the non-aqueous electrolyte and then sealing the container while reducing the pressure. Can be manufactured. The shape of the non-aqueous electrolyte secondary battery is not particularly limited, and may be any shape such as a thin plate (paper) type, a disc type, a cylindrical type, and a rectangular column type such as a rectangular parallelepiped. In addition, the manufacturing method of the member for nonaqueous electrolyte secondary batteries and a nonaqueous electrolyte secondary battery is not specifically limited, A conventionally well-known manufacturing method is employable.

The member for a non-aqueous electrolyte secondary battery of the present invention and the non-aqueous electrolyte secondary battery of the present invention have a puncture strength per unit area of the porous membrane of 26.0 gf / g / m ² or more. And the porous membrane which satisfies the said Formula (1) is included as a separator or the member of a separator. Therefore, when the electrode mixture expands during charging and discharging, the uniformity of the inter-electrode distance in the surface direction is maintained. Therefore, the non-aqueous electrolyte secondary battery including the non-aqueous electrolyte secondary battery member of the present invention and the non-aqueous electrolyte secondary battery of the present invention have excellent discharge output characteristics, and after the charge / discharge cycle. The rate characteristic maintenance rate is further improved.

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention. Furthermore, a new technical feature can be formed by combining the technical means disclosed in each embodiment.

  Hereinafter, although an example and a comparative example explain the present invention still in detail, the present invention is not limited to these examples.

[Measurement]
In the following Examples and Comparative Examples, the critical load value, the TD / MD ratio (T / M) of the distance to the critical load, and the nonaqueous electrolyte secondary battery in the separator for the nonaqueous electrolyte secondary battery The cycle characteristics were measured by the following method.

(Scratch test)
The critical load value and the TD / MD ratio (T / M) of the distance to the critical load were measured by the following scratch test. Measurement conditions other than those described below were measured under the same conditions as JIS R 3255. Moreover, the micro scratch test apparatus (made by CSEM Instruments) was used for the measuring apparatus.
(1) After the porous membranes manufactured in Examples and Comparative Examples are cut to 20 mm × 60 mm, the cut porous membrane and a glass preparation of 30 mm × 70 mm are applied to the entire surface of the preparation. By laminating using an Arabic Yamato aqueous liquid paste (manufactured by Yamato Co., Ltd.) diluted 5 times with water, thinly applied in a small amount of about 1.5 g / m ^2, and dried overnight at a temperature of 25 ° C. A test sample was prepared. In addition, at the time of the said bonding, it was careful so that a bubble might not enter between a porous membrane and glass preparations.
(2) The test sample prepared in step (1) was placed in a micro scratch test apparatus (manufactured by CSEM Instruments). The diamond indenter (conical shape with an apex angle of 120 ° and a tip radius of 0.2 mm) in the test apparatus is subjected to the test in a state where a vertical load of 0.1 N is applied on the test sample. The table in the apparatus is moved by a distance of 10 mm at a speed of 5 mm / min toward the TD of the porous membrane, during which stress (friction) generated between the diamond indenter and the test sample is generated. Force) was measured.
(3) A curve graph showing the relationship between the displacement of the stress measured in the step (2) and the moving distance of the table is created, and the critical load value and critical load at TD are reached from the curve graph. The distance to was calculated.
(4) The moving direction of the table was changed to MD, and the above steps (1) to (3) were repeated to calculate the critical load value and the distance to reach the critical load in MD.

(Cycle test)
With respect to a new non-aqueous electrolyte secondary battery manufactured in Examples and Comparative Examples and not subjected to a charge / discharge cycle, voltage range at 25 ° C .; 4.1 to 2.7 V, current value: 0.2 C 4 cycles of initial charge / discharge were performed with 1 cycle as the current value for discharging the rated capacity with a 1 hour rate discharge capacity in 1 hour to 1C (the same applies hereinafter).

Subsequently, the initial battery characteristic retention rate was calculated at 55 ° C. according to the following formula (4).
Initial battery characteristic retention ratio (%) = (20C discharge capacity / 0.2C discharge capacity) × 100 (4)
Subsequently, at 55 ° C., charging / discharging was carried out for 100 cycles, with charging / discharging at a constant current of charging current value: 1 C, discharging current value: 10 C as one cycle. Then, the battery characteristic maintenance rate after 100 cycles was calculated according to the following formula (5).
Battery characteristic maintenance ratio (%) = (20C discharge capacity at 100th cycle / 0.2C discharge capacity at 100th cycle) × 100 (5)
(Puncture strength measurement)
Using a handy compression tester (manufactured by Kato Tech Co., Ltd., model number: KES-G5), the porous film was fixed with a 12 mmφ washer, and the maximum stress (gf) when the pin was pierced at 200 mm / min was measured. The piercing strength was determined. A pin with a pin diameter of 1 mmΦ and a tip of 0.5R was used.

[Example 1]
<Manufacture of separator for non-aqueous electrolyte secondary battery>
Both were mixed so that the ultra high molecular weight polyethylene powder (GUR4032, manufactured by Ticona) was 72% by weight, and the weight average molecular weight 1000 polyethylene wax (FNP-0115, manufactured by Nippon Seiki Co., Ltd.) was 29% by weight. 100 parts by weight of the total of the ultra high molecular weight polyethylene and polyethylene wax, 0.4 parts by weight of antioxidant (Irg1010, manufactured by Ciba Specialty Chemicals), antioxidant (P168, manufactured by Ciba Specialty Chemicals) 0.1 parts by weight and 1.3 parts by weight of sodium stearate are added, and calcium carbonate (manufactured by Maruo Calcium Co., Ltd.) having an average pore size of 0.1 μm is added so that the ratio to the total volume is 37% by volume. The powder 1 was mixed with a Henschel mixer to obtain a mixture 1. Thereafter, the mixture 1 was melt-kneaded with a biaxial kneader to obtain a polyolefin resin composition 1. The polyolefin resin composition 1 was rolled with a roll having a peripheral speed of 4.0 m / min to produce a rolled sheet 1. Subsequently, the rolled sheet 1 is immersed in an aqueous hydrochloric acid solution (hydrochloric acid 4 mol / L, nonionic surfactant 0.5% by weight) to remove calcium carbonate from the rolled sheet 1 and subsequently at 100 ° C. for 7 The film was stretched 0.0 times (stretching temperature / magnification ratio = 14.3), and heat-fixed at 123 ° C. to obtain a porous membrane 1. The basis weight per unit area of the obtained porous membrane 1 was 5.4 g / m ² . The porous membrane 1 was used as a separator 1 for a nonaqueous electrolyte secondary battery.

<Production of non-aqueous electrolyte secondary battery>
(Positive electrode)
A commercially available positive electrode manufactured by applying LiNi _0.5 Mn _0.3 Co _0.2 O ₂ / conductive material / PVDF (weight ratio 92/5/3) to an aluminum foil was used. Cut the aluminum foil so that the size of the positive electrode active material layer formed on the positive electrode is 40 mm × 35 mm and the outer periphery of the positive electrode active material layer is 13 mm wide and no positive electrode active material layer is formed. A positive electrode was obtained. The positive electrode active material layer had a thickness of 58 μm and a density of 2.50 g / cm ³ .

(Negative electrode)
A commercially available negative electrode produced by applying graphite / styrene-1,3-butadiene copolymer / sodium carboxymethylcellulose (weight ratio 98/1/1) to a copper foil was used. Cut off the copper foil from the negative electrode so that the size of the portion where the negative electrode active material layer was formed was 50 mm × 40 mm and the outer periphery had a portion with a width of 13 mm and no negative electrode active material layer formed. A negative electrode was obtained. The thickness of the negative electrode active material layer was 49 μm, and the density was 1.40 g / cm ³ .

(Preparation of non-aqueous electrolyte secondary battery)
By laminating (arranging) the positive electrode, the porous membrane 1 (electrolyte secondary battery separator 1), and the negative electrode in this order in a laminate pouch, a nonaqueous electrolyte secondary battery member 1 was obtained. . At this time, the positive electrode and the negative electrode were disposed so that the entire main surface of the positive electrode active material layer of the positive electrode was included in the range of the main surface of the negative electrode active material layer of the negative electrode (overlaid on the main surface).

Subsequently, the non-aqueous electrolyte secondary battery member was put in a bag in which an aluminum layer and a heat seal layer were laminated, and 0.25 mL of the non-aqueous electrolyte was put in this bag. The non-aqueous electrolyte was prepared by dissolving LiPF ₆ at 1 mol / L in a mixed solvent obtained by mixing ethylene carbonate, ethyl methyl carbonate, and diethyl carbonate at a ratio of 3: 5: 2 (volume ratio). . And the non-aqueous-electrolyte secondary battery 1 was produced by heat-sealing the said bag, decompressing the inside of a bag.

[Example 2]
The amount of ultra high molecular weight polyethylene powder (GUR4032, manufactured by Ticona) is 70% by weight, the amount of polyethylene wax having a weight average molecular weight of 1000 (FNP-0115, manufactured by Nippon Seiki) is 30% by weight, and the average pore size A polyolefin resin composition 2 was prepared in the same manner as in Example 1 except that the amount of 0.1 μm calcium carbonate (manufactured by Maruo Calcium Co., Ltd.) was such that the ratio to the total volume was 36% by volume. . Subsequently, the polyolefin resin composition 2 was rolled with a roll having a peripheral speed of 3.0 m / min to produce a rolled sheet 2. Thereafter, the stretching temperature was set to 105 ° C., the stretching ratio was set to 6.2 times (stretching temperature / magnification ratio = 16.9), and heat setting was performed at 120 ° C. The sheet 2 was subjected to calcium carbonate removal, stretching, and heat setting to obtain a porous membrane 2. The basis weight per unit area of the obtained porous membrane 2 was 6.9 g / m ² . The porous membrane 2 was used as a separator 2 for a nonaqueous electrolyte secondary battery.

  A nonaqueous electrolyte secondary battery 2 was produced in the same manner as in Example 1 except that the porous membrane 2 was used instead of the porous membrane 1.

[Example 3]
After the porous membrane 1 obtained in Example 1 was cut to 5 cm × 5 cm, the cut porous membrane 1 was taped to a 15 cm × 15 cm frame SUS jig as shown in FIG. The porous membrane 3 was obtained by performing additional stretching so that the length in the MD direction was 1.5 times at 85 ° C. with a small tabletop testing machine (EZ-L) manufactured by Shimadzu Corporation.

  The porous membrane 3 was used as a separator 3 for a nonaqueous electrolyte secondary battery.

  A nonaqueous electrolyte secondary battery 3 was produced in the same manner as in Example 1 except that the porous membrane 3 was used instead of the porous membrane 1.

[Example 4]
After the porous membrane 1 obtained in Example 1 was cut to 5 cm × 5 cm, the cut porous membrane 1 was taped to a 15 cm × 15 cm frame SUS jig as shown in FIG. The porous membrane 4 was obtained by performing additional stretching so that the length in the MD direction was 1.2 times at 85 ° C. with a small tabletop testing machine (EZ-L) manufactured by Shimadzu Corporation.

  The porous membrane 4 was used as a separator 4 for a nonaqueous electrolyte secondary battery.

  A nonaqueous electrolyte secondary battery 4 was produced in the same manner as in Example 1 except that the porous membrane 4 was used instead of the porous membrane 1.

[Comparative Example 1]
After mixing both in a ratio of 68% by weight of ultrahigh molecular weight polyethylene powder (GUR2024, manufactured by Ticona) and 32% by weight of polyethylene wax having a weight average molecular weight of 1000 (FNP-0115, manufactured by Nippon Seiki) The total amount of the ultra high molecular weight polyethylene and polyethylene wax is 100 parts by weight, and the antioxidant (Irg1010, manufactured by Ciba Specialty Chemicals) is 0.4 part by weight, the antioxidant (P168, manufactured by Ciba Specialty Chemicals). ) 0.1 parts by weight, 1.3 parts by weight of sodium stearate, and calcium carbonate (manufactured by Maruo Calcium Co., Ltd.) with an average pore size of 0.1 μm was added so that the proportion of the total volume was 38% by volume. Was mixed with a Henschel mixer in powder form to obtain a mixture 5. Thereafter, the mixture 5 was melt-kneaded with a biaxial kneader to obtain a polyolefin resin composition 5. Subsequently, the polyolefin resin composition 5 was rolled with a roll having a peripheral speed of 2.5 m / min to produce a rolled sheet 5. Then, the calcium carbonate is removed by immersing the rolled sheet 5 in a hydrochloric acid aqueous solution (hydrochloric acid 4 mol / L, nonionic surfactant 0.5% by weight), and subsequently stretched 6.2 times at 100 ° C. (Stretching temperature / magnification ratio = 16.1) and heat-fixed at 126 ° C. to obtain a porous membrane 5. The basis weight per unit area of the obtained porous membrane 5 was 6.4 g / m ² . The porous membrane 5 was used as a separator 5 for a nonaqueous electrolyte secondary battery.

  A nonaqueous electrolyte secondary battery 5 was produced in the same manner as in Example 1 except that the porous membrane 5 was used instead of the porous membrane 1.

[Example 5]
After the porous membrane 5 obtained in Comparative Example 1 was cut to 5 cm × 5 cm, the cut porous membrane 5 was fixed to a SUS jig having a 15 cm × 15 cm frame as shown in FIG. The porous membrane 6 was obtained by performing additional stretching so that the length in the MD direction was 1.5 times at 85 ° C. with a small bench tester (EZ-L) manufactured by Shimadzu Corporation.

  The porous membrane 6 was used as a separator 6 for a nonaqueous electrolyte secondary battery.

  A nonaqueous electrolyte secondary battery 6 was produced in the same manner as in Example 1 except that the porous membrane 6 was used instead of the porous membrane 1.

[Comparative Example 2]
A commercially available polyolefin separator (weight per unit area: 13.9 g / m ² ) was used as the porous membrane 7 (separator 7 for non-aqueous electrolyte secondary battery).

  A nonaqueous electrolyte secondary battery 7 was produced in the same manner as in Example 1 except that the porous membrane 7 was used instead of the porous membrane 1.

  Table 1 below shows the peripheral speed of the rolling rolls, the stretching temperature, the stretching ratio, and the ratio of the stretching temperature / stretching ratio in Examples 1 and 2 and Comparative Example 1.

[Measurement result]
Using the non-aqueous electrolyte secondary battery separators 1 to 7 obtained in Examples 1 to 5 and Comparative Examples 1 and 2, the above-described scratch test was performed, and “critical load” and “criticality” in TD and MD were performed. The “distance to load” was measured. The results are shown in Table 2.

  Moreover, the cycle characteristics of the nonaqueous electrolyte secondary batteries 1 to 7 obtained in Examples 1 to 5 and Comparative Examples 1 and 2 were measured by the above-described method. The results are shown in Table 2.

[Conclusion]
As shown in Table 2, the value of “1-T / M” exceeds 0.54, that is, the value of “T / M” is less than 0.46, and the distance to the critical load in the scratch test is different. The non-aqueous electrolyte secondary batteries 5 and 7 including the non-aqueous secondary battery separators 5 and 7 manufactured in Comparative Examples 1 and 2 having a high degree of polarity have rate characteristics after 100 cycles (battery characteristics maintenance ratio). ) Was remarkably low at 37% and 18%.

  On the other hand, the value of “1-T / M” is 0.00 to 0.54, that is, the value of “T / M” is 0.45 to 1.00, and the distance to the critical load in the scratch test is The non-aqueous secondary batteries 1 to 4 and 6 including the separators 1 to 4 and 6 for the non-aqueous electrolyte secondary batteries manufactured in Examples 1 to 5 having small anisotropy are rate characteristics after 100 cycles. (Battery characteristics maintenance ratio) was 45% or more, and it was confirmed that the battery characteristics were superior.

  The separator for a non-aqueous electrolyte secondary battery and the laminated separator for a non-aqueous electrolyte secondary battery of the present invention can be suitably used for the production of a non-aqueous electrolyte secondary battery having excellent discharge output characteristics, particularly cycle characteristics. it can.

1 Diamond indenter 2 Substrate (Glass preparation)
3 Porous membrane mainly composed of polyolefin resin

Claims (8)

A separator for a non-aqueous electrolyte secondary battery comprising a porous film mainly composed of a polyolefin-based resin,
The puncture strength with respect to the basis weight per unit area of the porous membrane is 26.0 gf / g / m ² or more, and
The value represented by following formula (1) exists in the range of 0.00 or more and 0.54 or less, The separator for nonaqueous electrolyte secondary batteries characterized by the above-mentioned.
| 1-T / M | (1)
(In Formula (1), T represents a distance to a critical load in a scratch test under a constant load of 0.1 N in TD, and M is a scratch test in a scratch test under a constant load of 0.1 N in MD. Represents the distance to the critical load.) The value represented by following formula (2) exists in the range of 0.00 or more and 0.54 or less, The separator for non-aqueous-electrolyte secondary batteries of Claim 1 characterized by the above-mentioned.
1-T / M (2)
(In Formula (2), T represents a distance to a critical load in a scratch test under a constant load of 0.1 N in TD, and M is a scratch test in a scratch test under a constant load of 0.1 N in MD. Represents the distance to the critical load.)   A laminated separator for a nonaqueous electrolyte secondary battery, wherein a porous layer is laminated on at least one surface of the separator for a nonaqueous electrolyte secondary battery according to claim 1 or 2.   The laminated separator for a nonaqueous electrolyte secondary battery according to claim 3, wherein the porous layer contains a heat resistant resin.   The laminated separator for a nonaqueous electrolyte secondary battery according to claim 3 or 4, wherein the porous layer contains a polyvinylidene fluoride resin.   The laminated separator for a non-aqueous electrolyte secondary battery according to any one of claims 3 to 5, wherein the porous layer contains insulating fine particles.   The positive electrode, the separator for a non-aqueous electrolyte secondary battery according to claim 1 or 2, or the laminated separator for a non-aqueous electrolyte secondary battery according to any one of claims 3 to 6, and a negative electrode. The member for nonaqueous electrolyte secondary batteries arranged in order.   The non-aqueous electrolyte secondary battery comprising the separator for a non-aqueous electrolyte secondary battery according to claim 1 or 2 or the laminated separator for a non-aqueous electrolyte secondary battery according to any one of claims 3 to 6. Next battery.

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