CN116247378A

CN116247378A - Laminated separator for nonaqueous electrolyte secondary battery

Info

Publication number: CN116247378A
Application number: CN202211565962.2A
Authority: CN
Inventors: 堀江健作; 古川洵; 桥脇弘树
Original assignee: Sumitomo Chemical Co Ltd
Current assignee: Sumitomo Chemical Co Ltd
Priority date: 2021-12-07
Filing date: 2022-12-07
Publication date: 2023-06-09
Also published as: JP2023084694A; KR20230085881A

Abstract

The invention aims to inhibit meandering and winding deviation during winding. In a laminated separator in which a porous layer is laminated on one surface of a polyolefin porous film, the ratio of the intensity of a peak derived from an amide bond or a bond other than an amide bond to the intensity of a peak derived from the polyolefin porous film in an IR spectrum measured with the surface on the opposite side from the porous layer as a target is less than 0.02.

Description

Laminated separator for nonaqueous electrolyte secondary battery

Technical Field

The present invention relates to a laminated separator for a nonaqueous electrolyte secondary battery, and more particularly, to a laminated separator for a nonaqueous electrolyte secondary battery in which a porous layer is laminated on a polyolefin porous film.

Background

Nonaqueous electrolyte secondary batteries, particularly lithium ion secondary batteries, have been widely used as batteries for personal computers, mobile phones, mobile information terminals, and the like due to their high energy density, and have recently been developed as vehicle-mounted batteries.

The charge termination voltage in the conventional nonaqueous electrolyte secondary battery is 4.1 to 4.2V (4.2 to 4.3V (vs Li/Li) ⁺ ) About). In contrast, in recent nonaqueous electrolyte secondary batteries, the use ratio of the positive electrode is increased by increasing the charge termination voltage to 4.3V or higher than conventional nonaqueous electrolyte secondary batteries, thereby increasing the capacity of the battery. For this reason, it is important that the resin contained in the porous layer constituting the laminated separator for a nonaqueous electrolyte secondary battery does not undergo denaturation even under high-voltage conditions.

As such a resin, there is a resin having a structure in which some of the amide bonds in the polyamide constituting the porous layer of the conventional laminated separator for a nonaqueous electrolyte secondary battery are replaced with bonds having strong electron withdrawing properties other than amide bonds, that is, a resin having an amide bond and bonds other than amide bonds. Specific examples of the resin having an amide bond and a bond other than an amide bond include a copolymer of 4,4' -diaminodiphenyl sulfone (DDS) and an amide described in patent document 1.

[ Prior Art literature ]

[ patent literature ]

Japanese patent application laid-open No. 2004-269655

Disclosure of Invention

[ problem ] to be solved by the invention

However, in a laminated separator for a nonaqueous electrolyte secondary battery in which a porous layer containing a resin having an amide bond and a bond other than an amide bond is laminated on a polyolefin porous film as described in patent document 1, meandering and winding deviation may occur in various winding steps such as winding with a loop (loop) at the time of slitting.

[ means for solving the problems ]

As a result of intensive studies, the inventors of the present invention have found that the occurrence of hunting and winding displacement can be suppressed by depositing small molecules, which are produced as by-products when the resin having the amide bond and a bond other than the amide bond is prepared, on the surface of the laminated separator for a nonaqueous electrolyte secondary battery on the opposite side of the porous layer, and by reducing the amount of the deposited small molecules.

The present invention includes the inventions shown in the following [1] to [6 ].

[1] A laminated separator for a nonaqueous electrolyte secondary battery, wherein a porous layer is laminated on one surface of a polyolefin porous film,

the porous layer contains at least one resin having an amide bond and a bond other than the amide bond,

the peak ratio represented by the following formula (1) is less than 0.02.

Peak ratio=peak intensity a/peak intensity B (1)

(in the formula (1), the peak intensity A is the intensity of a peak originating from the amide bond and a bond other than the amide bond in an IR spectrum measured by the ATR method, with respect to a surface opposite to a surface on which the porous layer is laminated of the polyolefin porous film, and the peak intensity B is the intensity of a peak originating from the bond in the polyolefin porous film in the IR spectrum.)

[2]According to [1]]The peak intensity A in the formula (1) is the IR spectrum measured by ATR method, which is the opposite side of the surface of the polyolefin porous film on which the porous layer is laminated, and is present at 1570cm ^-1 ～1620cm ^-1 The intensity of the peak in the range of (c),

the peak intensity B in the above formula (1) is the number of waves 1450cm in the IR spectrum ^-1 ～1550cm ^-1 Intensity of peaks in the range of (2).

[3] The laminated separator for a nonaqueous electrolyte secondary battery according to [1] or [2], wherein at least one of the resins having an amide bond and a bond other than an amide bond comprises:

a block A comprising a unit represented by the following formula (2) as a main component,

-(NH-Ar ¹ -NHCO-Ar ² -CO) -type (2)

And a block copolymer of a block B mainly composed of a unit represented by the following formula (3).

-(NH-Ar ³ -NHCO-Ar ⁴ -CO) -type (3)

(in the formula (2) and the formula (3),

Ar ¹ 、Ar ² 、Ar ³ and Ar is a group ⁴ It may be different in each unit and,

Ar ¹ 、Ar ² 、Ar ³ and Ar is a group ⁴ Each independently represents a 2-valent group having 1 or more aromatic rings,

all Ar ¹ More than 50% of the aromatic hydrocarbon compounds have a structure in which 2 aromatic rings are linked by sulfonyl bonds,

all Ar ³ Less than 50% of the aromatic hydrocarbon compounds have a structure in which 2 aromatic rings are linked by sulfonyl bonds,

all Ar ¹ And Ar is a group ³ 10 to 70% of the aromatic hydrocarbon compounds have a structure in which 2 aromatic rings are linked by sulfonyl bonds. )

[4] The laminated separator for a nonaqueous electrolyte secondary battery according to any one of [1] to [3], wherein the porous layer further comprises a filler,

the filler content is 20 wt% to 90 wt% based on the weight of the entire porous layer.

[5] A member for a nonaqueous electrolyte secondary battery, wherein the laminated separator for a nonaqueous electrolyte secondary battery described in any one of [1] to [4] and the negative electrode are sequentially arranged.

[6] A nonaqueous electrolyte secondary battery comprising the laminated separator for nonaqueous electrolyte secondary batteries according to any one of [1] to [4 ].

[ Effect of the invention ]

The laminated separator for a nonaqueous electrolyte secondary battery according to one embodiment of the present invention can suppress occurrence of meandering and winding displacement when winding is performed at the time of slitting and at the time of battery assembly.

Detailed Description

Hereinafter, an embodiment of the present invention will be described, but the present invention is not limited thereto. The present invention is not limited to the configurations described below, and various modifications can be made within the scope of the claims, and embodiments obtained by appropriately combining the technical means disclosed in the respective different embodiments are also included in the technical scope of the present invention. Unless otherwise specified in the present specification, "a to B" representing a numerical range means "a or more and B or less".

Embodiment 1: laminated separator for nonaqueous electrolyte secondary battery

A laminated separator for a nonaqueous electrolyte secondary battery according to embodiment 1 of the present invention (hereinafter also simply referred to as "laminated separator") is a laminated separator for a nonaqueous electrolyte secondary battery in which a porous layer containing at least one resin having an amide bond and a bond other than an amide bond is laminated on one surface of a polyolefin porous film, and the peak ratio represented by the following formula (1) is less than 0.02.

Peak ratio=peak intensity a/peak intensity B (1)

In the above formula (1), the peak intensity a is the intensity of a peak derived from the amide bond and a bond other than the amide bond in an IR spectrum measured by an ATR method, with respect to a surface opposite to a surface on which the porous layer is laminated of the polyolefin porous film; the peak intensity B is the intensity of the peak derived from the bond in the polyolefin porous film in the IR spectrum.

< Peak ratio >)

The laminated separator according to one embodiment of the present invention is a laminate in which the porous layer is laminated on one surface of a polyolefin porous film. When the porous layer is laminated, a part of the resin having amide bonds and bonds other than amide bonds constituting the porous layer, specifically, small molecules described later, pass through the pores inside the porous layer of the polyolefin porous membrane and are deposited on the surface of the laminated separator opposite to the porous layer. The surface of the laminated separator opposite to the porous layer is the surface of the polyolefin porous film opposite to the surface on which the porous layer is laminated.

As described later, the small molecule is a part of the resin having an amide bond and a bond other than an amide bond, and has an amide bond and a bond other than an amide bond. The "peak intensity a" is the intensity of a peak derived from the above amide bond and a bond other than the above amide bond. The "peak intensity B" is the intensity of a peak derived from a bond in the polyolefin porous membrane.

The peaks derived from the amide bond and the bond other than the amide bond and the peaks derived from the bond in the polyolefin porous membrane are not particularly limited as long as they can be distinguished from each other and the "peak intensity a" and the "peak intensity B" can be accurately measured. The peak derived from the amide bond may be, for example, a peak derived from stretching vibration of a c=o group of the amide bond. The peak derived from a bond other than the amide bond may be, for example, a peak derived from stretching vibration of o=s=o group of the sulfonyl bond. The peak derived from the stretching vibration of the c=o group of the amide bond and the stretching vibration of the o=s=o group of the sulfonyl bond, specifically, the peak exists at 1570cm ^-1 ～1620cm ^-1 Peaks in the range of (2). The peak derived from the bond in the polyolefin porous membrane may be, for example, a peak derived from stretching vibration of a c—h group of polyolefin. The peak of the stretching vibration of the C-H group derived from the polyolefin, specifically, the peak of the stretching vibration existing at 1450cm ^-1 ～1550cm ^-1 Peaks in the range of (2). Here, the intensity of a peak is related to the content of a compound having a group or bond corresponding to the peak.

Accordingly, the "peak ratio represented by formula (1)" represents a ratio of the content of the small molecule to the content of the polyolefin in the surface layer portion of the surface of the laminated separator opposite to the porous layer. Accordingly, the "peak ratio represented by the formula (1)" is a parameter indicating the amount of the small molecules deposited on the surface opposite to the porous layer in the laminated separator.

Here, in a conventional laminated separator in which a porous layer containing a resin having an amide bond and a bond other than an amide bond is laminated on a surface of a polyolefin porous film, it is considered that irregularities are generated on a surface on the opposite side of the porous layer due to the small molecules deposited on a surface on the opposite side of the porous layer in the laminated separator. As a result, the slipping property of the laminated separator is reduced, and as a result, meandering and winding deviation may occur during winding.

On the other hand, in the laminated separator according to one embodiment of the present invention, the peak ratio represented by the formula (1) is a small value of less than 0.02, and the small molecules deposited on the surface of the laminated separator opposite to the porous layer are small in weight. Thus, the reduction in the sliding property of the laminated separator for a nonaqueous electrolyte secondary battery due to the deposition of the small molecules on the surface opposite to the porous layer can be suppressed. Accordingly, the laminated separator according to one embodiment of the present invention can suppress occurrence of hunting and winding displacement during slitting and winding at the time of battery assembly due to the reduction of the slidability.

The peak ratio represented by the formula (1) is preferably 0.015 or less from the viewpoint of suitably suppressing occurrence of the meandering and winding displacement.

On the other hand, in the laminated separator according to one embodiment of the present invention, a value of "the peak ratio represented by the formula (1)" of more than 0 means that a part of the resin component constituting the porous layer, that is, a part of the resin component constituting the porous layer, is present in the surface layer portion of the surface opposite to the surface on which the porous layer is laminated of the polyolefin porous film constituting the laminated separator. Here, it is considered that since a part of the resin component constituting the porous layer enters the polyolefin porous film, the affinity and adhesiveness between the polyolefin porous film and the porous layer are improved. As a result, it is considered that the adhesion between the polyolefin porous film and the porous layer is improved in the laminated separator, and the occurrence of deviation between the polyolefin porous film and the porous layer can be suitably suppressed when the laminated separator is wound, for example.

In the laminated separator, the peak ratio represented by the formula (1) is preferably 0.001 or more, more preferably 0.003 or more, from the viewpoint of improving the adhesion between the polyolefin porous film and the porous layer.

Calculation method of < Peak ratio >)

In one embodiment of the present invention, the calculation of the peak ratio represented by the above-mentioned "formula (1)" may be performed by a method comprising the following steps (a) to (C).

(A) The step of obtaining an IR spectrum by measuring the surface of the laminated separator on the opposite side of the porous layer by ATR method is performed.

(B) And (c) obtaining "peak intensity a" and "peak intensity B" based on the IR spectrum obtained in the step (a).

(C) And (c) calculating a peak ratio represented by the formula (1) based on the "peak intensity a" and the "peak intensity B" obtained in the step (B).

In the step (a), measurement by the ATR method can be performed using a commercially available reflection type infrared analyzer. The measurement conditions are not particularly limited as long as the "peak intensity a" and the "peak intensity B" can be measured in the obtained IR spectrum.

In the step (C), the "peak intensity a" can be calculated by a method comprising the following steps (a) to (d).

(a) And (c) measuring the intensity of a peak derived from the amide bond and the bond other than the amide bond in the resin having the amide bond and the bond other than the amide bond contained in the porous layer in the IR spectrum obtained in the step (B), and taking the measured intensity of the peak as "measured peak intensity a". The peak derived from the amide bond and bonds other than the amide bond is, for example, present at 1570cm ^-1 ～1620cm ^-1 Is a peak of the range of (2).

(b) And (c) a step of obtaining an IR spectrum by performing ATR measurement on the same surface of the polyolefin porous film as the surface to be measured in the step (a), wherein the polyolefin porous film does not contain the resin having an amide bond and a bond other than the amide bond.

(c) In the IR spectrum obtained in the step (b), the above-mentioned acyl group derived from the peak related to the intensity measured in the step (a) is measuredAnd a step of setting the measured peak intensity as "base peak intensity A" as the peak intensity of the bond identical to the bond other than the amide bond. In addition, as in the step (a), the peak derived from the amide bond and the bond other than the amide bond is, for example, present at 1570cm ^-1 ～1620cm ^-1 Is a peak of the range of (2).

(d) And (c) subtracting the "base peak intensity a" obtained in the step (c) from the "measured peak intensity a" obtained in the step (a), thereby calculating the "peak intensity a".

Therefore, the "peak intensity represented by the formula (1)" can be calculated specifically by the following formula (1').

"peak ratio represented by formula (1) = (" measured peak intensity a "-" base peak intensity a ")/" peak intensity B "formula (1')

In the step (b), the "base peak strength a" may be measured in advance as the polyolefin porous film containing no resin having an amide bond or a bond other than an amide bond, using the polyolefin porous film constituting the laminated separator before the laminated separator is produced. Alternatively, the "base peak strength a" may be measured by washing the laminated separator obtained by the ATR method in the step (a) with a solvent capable of completely dissolving the resin having an amide bond and a bond other than an amide bond, thereby obtaining a polyolefin porous film from which the resin having an amide bond and a bond other than an amide bond has been completely removed.

< resin having an amide bond and a bond other than an amide bond >

The porous layer according to one embodiment of the present invention contains at least 1 resin having an amide bond and a bond other than an amide bond. The resin having an amide bond and a bond other than an amide bond may be 1 resin, or may be a mixture of 2 or more resins.

The resin having an amide bond and a bond other than the amide bond has a structure in which a 2-valent group is bonded to a chemical bond, and the chemical bond is composed of an amide bond and a bond other than the amide bond. The resin having an amide bond and a bond other than an amide bond may be prepared by a polymerization method in which the 2-valent groups are sequentially bonded via the chemical bond. In the resin having an amide bond and a bond other than an amide bond, the proportion of the amide bond among the chemical bonds is preferably 45 to 85%, more preferably 55 to 75%, from the viewpoint of heat resistance of the porous layer.

The resin having an amide bond and a bond other than an amide bond obtained by the above production method may contain a high molecular weight chain polymer composed of a predetermined number or more of the above 2-valent groups and a predetermined number or more of the above chemical bonds. On the other hand, in the above production method, a low molecular weight chain polymer having a smaller number of the 2-valent groups and the chemical bonds than the chain polymer is produced as a byproduct because the linkage is interrupted in the middle.

In addition, in the course of the preparation of the resin having an amide bond and a bond other than an amide bond by the above preparation method, an intermediate product having a smaller number of the 2-valent groups and the chemical bonds than the chain polymer having a higher molecular weight is produced. Here, as another by-product, a cyclic component is formed by condensing both ends in the same molecule of the above intermediate product with each other. The cyclic component has a structure in which the 2-valent group is bonded to the chemical bond and has no terminal.

As described above, in one embodiment of the present invention, the cyclic component may be formed from an intermediate product having a smaller number of the 2-valent groups and the chemical bonds than the high-molecular weight chain polymer. Therefore, the number of the 2-valent groups and the chemical bonds in the cyclic component is reduced as compared with the high molecular weight chain polymer. Thus, the weight average molecular weight of the cyclic component is also smaller than that of the high molecular weight chain polymer.

Specifically, in one embodiment of the present invention, the molecular weight of the high molecular weight chain polymer is preferably 0.5 to 5.0dL/g, more preferably 1.0 to 2.0dL/g, and even more preferably 1.1 to 1.9dL/g, when expressed as intrinsic viscosity. In one embodiment of the present invention, the molecular weight of the low-molecular weight chain polymer is preferably 0.5 to 3.0dL/g, more preferably 0.7 to 1.5dL/g, when expressed as intrinsic viscosity.

The weight average molecular weight of the low molecular weight chain polymer and the cyclic component is small, and the low molecular weight chain polymer and the cyclic component are small molecules as compared with the high molecular weight chain polymer. Therefore, the low molecular weight chain polymer and the cyclic component belong to the small molecule deposited on the surface of the laminated separator opposite to the porous layer.

The above-mentioned 2-valent group is not particularly limited. In one embodiment of the present invention, the 2-valent groups preferably include 2-valent aromatic groups, and more preferably, all of the 2-valent groups are 2-valent aromatic groups. The above-mentioned 2-valent group may be 1 kind of group or 2 or more kinds of groups.

In the present specification, "a 2-valent aromatic group" means a 2-valent group comprising an unsubstituted aromatic ring or a substituted aromatic ring, preferably, a 2-valent group composed of an unsubstituted aromatic ring or a substituted aromatic ring. The aromatic ring represents a cyclic compound satisfying the shock rule. Examples of the aromatic ring include benzene, naphthalene, anthracene, azulene, pyrrole, pyridine, furan, and thiophene. In one embodiment of the present invention, the aromatic ring is composed of only carbon atoms and hydrogen atoms. In one embodiment of the present invention, the aromatic ring is a benzene ring or condensed rings of 2 or more benzene rings (naphthalene, anthracene, etc.).

In one embodiment of the present invention, the substituent of the 2-valent group is not particularly limited. In one embodiment of the present invention, the substituent of the 2-valent group is preferably a substituent having electron withdrawing property in order to obtain a porous layer for a nonaqueous electrolyte secondary battery having high voltage resistance, which is not easily denatured even under high voltage conditions. The electron withdrawing substituent is not particularly limited, and examples thereof include a carboxyl group, an alkoxycarbonyl group, a nitro group, a halogen atom, and the like.

The bond other than the amide bond is not particularly limited, and examples thereof include a sulfonyl bond, an ethylenic bond (e.g., a C1 to C5 ethylenic bond), an ether bond, an ester bond, an imide bond, a ketone bond, and a thioether bond. The number of bonds other than the amide bond may be 1 or 2 or more.

In one embodiment of the present invention, the bonds other than the amide bonds preferably include bonds having a higher electron withdrawing property than the amide bonds, from the viewpoint of obtaining a porous layer having high voltage resistance. In addition, from the viewpoint of further improving the high voltage resistance of the porous layer, the proportion of the bonds having higher electron withdrawing property than the amide bonds in the chemical bonds is more preferably 15 to 35%, and still more preferably 25 to 35%.

Examples of the bond having higher electron withdrawing property than the amide bond include a sulfonyl bond, an ester bond, and the like among the bonds other than the amide bond listed above.

Specifically, examples of the resin having an amide bond and a bond other than an amide bond include polyamide and polyamideimide, and a copolymer of polyamide or polyamideimide and a polymer having 1 or more bonds selected from the group consisting of sulfonyl bonds, ether bonds and ester bonds. The copolymer may be a block copolymer or a random copolymer.

The polyamide is preferably an aromatic polyamide. Examples of the aromatic polyamide include wholly aromatic polyamide (aramid resin) and semiaromatic polyamide. The aromatic polyamide is preferably a wholly aromatic polyamide. Examples of the aromatic polyamide include para-aramid and meta-aramid.

The polyamide-imide is preferably an aromatic polyamide-imide. Examples of the aromatic polyamideimide include wholly aromatic polyamideimide and semiaromatic polyamideimide. The aromatic polyamide-imide is preferably a wholly aromatic polyamide-imide.

Examples of the polymer having 1 or more bonds selected from the group consisting of sulfonyl bonds, ether bonds and ester bonds constituting the copolymer include polysulfone, polyether, polyester and the like.

The resin having an amide bond and a bond other than an amide bond is not particularly limited, and examples thereof include wholly aromatic polyamide resins having a unit represented by the following formula (4) as a main component. Here, "as a main component" means that the proportion of the unit represented by the formula (4) is 50% or more, preferably 80% or more, more preferably 90% or more, and even more preferably 95% or more, of all the units contained in the wholly aromatic polyamide resin.

-(NH-Ar ⁵ -NHCO-Ar ⁶ -CO) -formula (4).

Ar in formula (4) ⁵ And Ar is a group ⁶ Which may be different in each cell. Ar (Ar) ⁵ And Ar is a group ⁶ Each independently is a 2-valent group having 1 or more aromatic rings.

All Ar ⁵ More than 50% of the aromatic compounds have a structure in which 2 aromatic rings are linked by sulfonyl bonds. Ar having this structure ⁵ The lower limit of the ratio of (2) is preferably Ar ⁵ More preferably, the total content is 60% or more, and still more preferably 80% or more. As-Ar of such a structure ¹ Examples of the group-include a 4,4' -diphenylsulfonyl group, a 3,4' -diphenylsulfonyl group and a 3,3' -diphenylsulfonyl group.

Ar having a structure in which 2 aromatic rings are not bonded to a sulfonyl bond ⁵ -and-Ar ⁶ Examples of the structure are as follows.

[ chemical formula 1 ]

In one embodiment of the present invention, ar is a structure in which 2 aromatic rings are bonded as a sulfonyl bond ⁵ -4, 4' -diphenylsulfonyl. In one embodiment of the present invention, ar is not a structure in which 2 aromatic rings are bonded to a sulfonyl bond ⁵ -and-Ar ⁶ -p-phenyl.

In one embodiment of the present invention, the wholly aromatic polyamide-based resin having the unit represented by the formula (4) as a main component is, for example, an aromatic polyamide having (i) a diamine unit derived from 4,4' -diaminodiphenyl sulfone and p-phenylenediamine, and (ii) a dicarboxylic acid unit derived from terephthalic acid (or halogenated terephthalic acid). In another embodiment of the present invention, the wholly aromatic polyamide resin containing a unit represented by the formula (4) as a main component is an aromatic polyamide having (i) a diamine unit derived from 4,4' -diaminodiphenyl sulfone and (ii) a dicarboxylic acid unit derived from terephthalic acid (or halogenated terephthalic acid). Monomers (monommers) of these units are readily available and also easy to handle.

The wholly aromatic polyamide resin having the unit represented by the formula (4) as a main component may have a structure composed of units other than the unit represented by the formula (4). Examples of such a structure include a polyimide skeleton.

The wholly aromatic polyamide resin mainly composed of the unit represented by the formula (4) may be used in an amount of 1 or 2 or more.

The wholly aromatic polyamide resin mainly composed of the unit represented by the formula (4) may be synthesized by a conventional method. For example, using NH ₂ -Ar ⁵ -NH ₂ Diamines represented and X-C (=o) -Ar ⁶ When a diacid halide represented by (C (=o) -X (X is a halogen atom such as F, cl, br, I) is polymerized as a monomer according to a known polymerization method for an aromatic polyamide, a wholly aromatic polyamide resin containing a unit represented by the formula (4) as a main component can be synthesized.

Examples of the resin having an amide bond and a bond other than an amide bond include, for example, a block copolymer having a block A mainly composed of a unit represented by the following formula (2) and a block B mainly composed of a unit represented by the following formula (3).

-(NH-Ar ¹ -NHCO-Ar ² -CO) -type (2)

-(NH-Ar ³ -NHCO-Ar ⁴ -CO) -type (3)

Ar in the formula (2) and the formula (3) ¹ 、Ar ² 、Ar ³ And Ar is a group ⁴ May be different in each unit, ar ¹ 、Ar ² 、Ar ³ And Ar is a group ⁴ Each independently is a 2-valent group having 1 or more aromatic rings, all Ar ¹ More than 50% of the aromatic groups have a structure in which 2 aromatic rings are linked by sulfonyl bonds, and all Ar ³ Less than 50% of the aromatic groups have a structure in which 2 aromatic rings are linked by sulfonyl bonds, and all Ar ¹ And Ar is a group ³ Of these, 10 to 70%, preferably 10 to 50%, have 2 fragrances linked by sulfonyl linkages A ring structure.

In the block copolymer, it is preferable that 50% or more of the units represented by the formula (2) contained in the block A be 4,4' -diphenylsulfonyl terephthalamide and 50% or more of the units represented by the formula (3) contained in the block B be paraphenylene terephthalamide. The block copolymer preferably has a triblock structure of the block B, the block a, and the block B. Further, the number of the units represented by the formula (2) contained in the block a is preferably 10 to 1000, and the number of the units represented by the formula (3) contained in the block B is preferably 10 to 500, which correspond to the mode value of the molecular weight distribution of the block copolymer.

Further, another example of the resin having an amide bond and a bond other than an amide bond is a polymer having 5 to 200 units represented by the formula (3) without containing the unit represented by the formula (2).

In one embodiment of the present invention, the resin having an amide bond and a bond other than an amide bond may be prepared by a polymerization method in which a diamine component and a dicarboxylic acid halide component are used and the components are sequentially connected as described above. Here, when the concentration of the above-mentioned component in the solvent is high, a condensation reaction between different molecules tends to occur, and a condensation reaction between both terminals in the same molecule tends to be difficult to occur, so that it is difficult to produce the above-mentioned cyclic component. In other words, the amount of the small molecules deposited on the opposite side of the porous layer of the polyolefin porous film in the laminated separator can be reduced. As a result, the peak ratio represented by the formula (1) can be controlled to a proper range.

Here, in the above-described polymerization method, controlling the concentration of the above-described components in the solvent means controlling the concentration of the polymer produced in the solvent. In one embodiment of the present invention, the polymer concentration is preferably 0.5 to 10.0 wt%, and more preferably 1.0 to 7.0 wt%. In this way, the amount of molecules belonging to the small molecules produced, in other words, the amount of the small molecules deposited on the opposite side of the porous layer of the polyolefin porous film in the laminated separator can be controlled to a suitable range.

In one embodiment of the present invention, the method for producing a resin having an amide bond and a bond other than an amide bond may include a step of polymerizing a diamine component and a dihalide component, and sequentially bonding the 2-valent groups with the amide bond. Here, the amount of the small molecule "low molecular weight chain polymer" produced may be controlled to a suitable range by adjusting the reaction temperature and/or the water content at the time of polymerization of the diamine component and the acid halide component, and as a result, the peak ratio represented by the formula (1) may be controlled to a suitable range.

In detail, the amide bond is formed by an amino group (-NH) ₂ ) Is bonded to a carbon atom (C) of a carboxyl group (-C (=O) -). On the other hand, the dihalide component used for the reaction is reacted with water (H ₂ O) reaction, a carboxyl group (-C (=o) -OH) may be formed on at least either end. Here, since the carboxyl group and the amino group are difficult to react, when the carboxyl group is formed at the end of the polymer, the connection via the amide bond of the above-mentioned 2-valent group is interrupted.

When the reaction temperature of the polymerization is low, H is present in the reaction solvent ₂ The hydrolysis reaction of the added dihalide by O is suppressed, and the reaction for forming the amide bond is more likely to occur than the reaction for forming the carboxyl group. As a result, the amount of the "low molecular weight chain polymer" can be reduced to an appropriate range.

On the other hand, a certain temperature is also necessary to generate the reaction for forming the amide bond. Therefore, if the reaction temperature of the polymerization is too low, the reaction itself to form the amide bond may be difficult to occur.

When the water content of the polymerization is low, the reaction of the dicarboxylic acid dihalide with water to form a carboxyl group can be suppressed. As a result, the amount of the "low molecular weight chain polymer" can be reduced to an appropriate range.

In one embodiment of the present invention, the reaction temperature is preferably 10 ℃ or higher and 50 ℃ or lower, more preferably 20 ℃ or higher and 40 ℃ or lower. In one embodiment of the present invention, the water content is preferably 50ppm or more and 900ppm or less, more preferably 100ppm or more and 600ppm or less.

In one embodiment of the present invention, the content of the resin having an amide bond and a bond other than an amide bond in the porous layer is preferably 10 to 80% by weight, more preferably 20 to 70% by weight, based on the weight of the entire porous layer.

The intrinsic viscosity of the resin having an amide bond and a bond other than an amide bond is preferably 0.8 to 2.5g/dL, more preferably 1.0 to 2.0dL/g, and even more preferably 1.1 to 1.9dL/g, from the viewpoint of controlling the precipitation property.

[ Filler ]

The porous layer according to an embodiment of the present invention may contain a filler.

Examples of the types of the fillers include organic fillers and inorganic fillers.

Examples of the organic filler include homopolymers such as styrene, vinyl ketone, acrylonitrile, methyl methacrylate, ethyl methacrylate, glycidyl acrylate, and methyl acrylate, and copolymers of 2 or more kinds; fluororesins such as polytetrafluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-ethylene copolymer, polyvinylidene fluoride and the like; a melamine resin; urea resin; a polyolefin; polymethacrylate, and the like. The organic filler may be used alone or in combination of 2 or more. Among these organic fillers, polytetrafluoroethylene powder is preferred from the viewpoint of chemical stability.

Examples of the inorganic filler include materials composed of inorganic substances such as metal oxides, metal nitrides, metal carbides, metal hydroxides, carbonates, and sulfates. Specifically, examples thereof include powders of aluminum oxide (such as alumina), boehmite, silica, titania, magnesia, barium titanate, aluminum hydroxide, and calcium carbonate; minerals such as mica, zeolite, kaolin and talc. The inorganic filler may be used alone or in combination of 2 or more. Among these inorganic fillers, aluminum oxide is preferred from the viewpoint of chemical stability.

Examples of the shape of the filler include substantially spherical, plate-like, columnar, needle-like, whisker-like, and fibrous, and any particle can be used. For the reason of easy formation of uniform pores, substantially spherical particles are preferable.

The average particle diameter of the filler is preferably 0.01 to 1. Mu.m. In the present specification, the "average particle diameter of the filler" means an average particle diameter (D50) based on the volume of the filler. D50 means a particle diameter whose cumulative distribution on a volume basis is a value of 50%. The D50 can be measured, for example, by a laser diffraction particle size distribution analyzer (trade name: SALD2200, SALD2300, etc., manufactured by Shimadzu corporation).

The content of the filler is preferably 20 to 90% by weight, more preferably 30 to 80% by weight, based on the weight of the entire porous layer. If the content of the filler is within the above range, a porous layer having sufficient ion permeability can be obtained.

[ other Components ]

The porous layer according to one embodiment of the present invention may contain a resin having an amide bond and a bond other than an amide bond, and other components than a filler, within a range that does not impair the object of the present invention. As the other component, for example, a resin other than the resin having an amide bond and a bond other than an amide bond, and an additive which is generally usable in a porous layer for a nonaqueous electrolyte secondary battery may be contained. The other components may be 1 kind or a mixture of 2 or more kinds.

Examples of the resin other than the resin having an amide bond and a bond other than an amide bond include polyolefin; (meth) acrylate resins; fluorine-containing resin; a polyester resin; rubber; a resin having a melting point or glass transition temperature of 180 ℃ or higher; a water-soluble polymer; polycarbonates, polyacetals, polyetheretherketones, polybenzimidazoles, polyurethanes, melamine resins, and the like.

Examples of the additives include flame retardants, antioxidants, surfactants, and waxes.

[ polyolefin porous film ]

The laminated separator includes a polyolefin porous film. The polyolefin porous membrane has a plurality of linked pores in the inside thereof, and is capable of passing gas and liquid from one surface to the other. The polyolefin porous film may become a substrate for the laminated separator. The polyolefin porous film melts when the battery generates heat, thereby making the laminated separator nonporous, and thus can impart the shutdown function (shutdown) to the laminated separator.

Here, the "polyolefin porous film" is a porous film containing a polyolefin resin as a main component. The term "the polyolefin resin is used as a main component" means that the proportion of the polyolefin resin in the porous film is 50% by volume or more, preferably 90% by volume or more, and more preferably 95% by volume or more of the entire material constituting the porous film.

The polyolefin resin as the main component of the polyolefin porous film is not particularly limited, and examples thereof include homopolymers and copolymers obtained by polymerizing monomers such as ethylene, propylene, 1-butene, 4-methyl-1-pentene and/or 1-hexene as the thermoplastic resin. Namely, polyethylene, polypropylene, polybutylene, and the like as homopolymers, and ethylene-propylene copolymers as copolymers, and the like can be cited. The polyolefin porous film may be a layer containing these polyolefin resins alone or a layer containing 2 or more of these polyolefin resins. Among these, polyethylene is more preferable, and high molecular weight polyethylene mainly composed of ethylene is particularly preferable, since an excessive current can be prevented (turned off) at a relatively low temperature. The polyolefin porous film may contain components other than polyolefin within a range that does not impair the function thereof.

Examples of the polyethylene include low density polyethylene, high density polyethylene, linear polyethylene (ethylene- α -olefin copolymer), and ultra-high molecular weight polyethylene. Of these, ultra-high molecular weight polyethylene is more preferable, and weight average molecular weight 5X 10 is more preferable ⁵ ～15×10 ⁶ Is a high molecular weight component of (a). In particular, when the polyolefin resin contains a high molecular weight component having a weight average molecular weight of 100 ten thousand or more, the strength of the polyolefin porous film and the laminate separator for a nonaqueous electrolyte secondary battery can be improved, and thus it is more preferable。

The thickness of the polyolefin porous film is preferably 5 to 20. Mu.m, more preferably 7 to 15. Mu.m, and even more preferably 9 to 15. Mu.m. If the film thickness is 5 μm or more, the functions (shutdown functions and the like) required for the polyolefin porous film can be sufficiently obtained. If the film thickness is 20 μm or less, a thin laminated separator can be obtained.

The pore diameter of the pores of the polyolefin porous membrane is preferably 0.1 μm or less, more preferably 0.06 μm or less. This can provide sufficient ion permeability and can further prevent particles constituting the electrode from entering.

The gram weight per unit area of the polyolefin porous film is usually preferably 4 to 20g/m in order to improve the gravimetric energy density and volumetric energy density of the battery ² More preferably 5 to 12g/m ² 。

The air permeability of the polyolefin porous film is preferably 30 to 500s/100mL, more preferably 50 to 300s/100mL, in terms of Gurley value. Thus, the laminated separator can obtain sufficient ion permeability.

The porosity of the polyolefin porous film is preferably 20 to 80% by volume, more preferably 30 to 75% by volume. Thus, it is possible to have a higher electrolyte holding amount while preventing (shutting off) the flow of excessive current at a lower temperature.

The method for producing the polyolefin porous film is not particularly limited, and a known method can be used. For example, as described in Japanese patent No. 5476844, a method is mentioned in which a filler is added to a thermoplastic resin to form a film and then the filler is removed.

Specifically, for example, when the polyolefin porous film is formed of a polyolefin-based resin containing an ultrahigh molecular weight polyethylene and a low molecular weight polyolefin having a weight average molecular weight of 1 ten thousand or less, it is preferable from the viewpoint of production cost to produce the polyolefin porous film by a method comprising the following steps (1) to (4).

(1) A step of kneading 100 parts by weight of an ultra-high molecular weight polyethylene, 5 to 200 parts by weight of a low molecular weight polyolefin having a weight average molecular weight of 1 ten thousand or less, and 100 to 400 parts by weight of an inorganic filler such as calcium carbonate to obtain a polyolefin resin composition,

(2) A step of forming a sheet by using the polyolefin resin composition,

(3) A step of removing the inorganic filler from the sheet obtained in the step (2),

(4) And (3) stretching the sheet obtained in step (3).

In addition, the methods described in the above patent documents may also be used.

Further, as the polyolefin porous film, a commercially available product having the above-mentioned characteristics can be used.

[ physical Properties of laminated separator and porous layer for nonaqueous electrolyte Secondary Battery ]

The air permeability of the laminated separator is preferably 500s/100mL or less, more preferably 300s/100mL or less, in terms of Gurley number. The air permeability of the porous layer is preferably 400s/100mL or less, more preferably 200s/100mL or less, in terms of Gurley number. If the air permeability of the laminated separator and the porous layer is in the above range, it can be said that the laminated separator has sufficient ion permeability.

The air permeability of the porous layer can be calculated by Y-X, assuming that the air permeability of the polyolefin porous film is X and the air permeability of the laminated separator is Y. The air permeability of the porous layer can be adjusted by, for example, the intrinsic viscosity of the resin and the gram weight of the porous layer. In general, as the intrinsic viscosity of the resin becomes smaller, the gurley number also tends to become smaller. Further, when the grammage of the porous layer becomes small, the gurley value tends to become small.

The laminated separator may have other layers as required in addition to the polyolefin porous film and the porous layer. Examples of such a layer include an adhesive layer and a protective layer.

[ method for producing laminated separator for nonaqueous electrolyte secondary battery ]

The porous layer may be formed using a coating liquid in which the resin having an amide bond and a bond other than an amide bond and an optional filler are dissolved or dispersed in a solvent, to manufacture the laminated separator. 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 medium dispersion method. As the solvent, for example, N-methylpyrrolidone, N-dimethylacetamide, N-dimethylformamide, and the like can be used.

As a method for producing the laminated separator, for example, a method of preparing the coating liquid, coating the coating liquid on a polyolefin porous film, and drying the coating liquid to form the porous layer on the polyolefin porous film is mentioned.

As a method of applying the coating liquid to the polyolefin porous film, a known coating method such as doctor blade (knife), blade (blade), bar, gravure, or die can be used.

The method for removing the solvent (dispersion medium) is usually a drying method. The drying method includes natural drying, forced air drying, heating drying, and reduced pressure drying, but any method is possible as long as the solvent (dispersion medium) can be sufficiently removed. The solvent (dispersion medium) contained in the paint may be replaced with another solvent and then dried. As a method of removing the solvent (dispersion medium) after being replaced with another solvent, specifically, a method of replacing the solvent with a poor solvent having a low boiling point such as water, alcohol or acetone, precipitating the solvent, and drying the solvent is available.

Embodiment 2: nonaqueous electrolyte secondary battery member, embodiment 3: nonaqueous electrolyte secondary battery

The nonaqueous electrolyte secondary battery member according to embodiment 2 of the present invention is formed by arranging a positive electrode, a nonaqueous electrolyte secondary battery laminated separator according to embodiment 1 of the present invention, and a negative electrode in this order. The nonaqueous electrolyte secondary battery according to embodiment 3 of the present invention includes the laminated separator for a nonaqueous electrolyte secondary battery according to embodiment 1 of the present invention.

Therefore, both the member for a nonaqueous electrolyte secondary battery according to one embodiment of the present invention and the nonaqueous electrolyte secondary battery according to one embodiment of the present invention exert the effect of suppressing meandering and occurrence of winding displacement of the laminated separator at the time of assembly.

The nonaqueous electrolyte secondary battery according to an embodiment of the present invention generally has a structure in which the negative electrode and the positive electrode are arranged to face each other with the laminated separator interposed therebetween. In the nonaqueous electrolyte secondary battery, a battery element in which an electrolyte is impregnated in the structure is packaged in an exterior material. For example, the nonaqueous electrolyte secondary battery is a lithium ion secondary battery in which electromotive force is obtained by doping/dedoping lithium ions.

[ Positive electrode ]

As the positive electrode, for example, a positive electrode sheet having a structure in which an active material layer containing a positive electrode active material and a binder is formed on a current collector can be used. The active material layer may further contain a conductive agent.

Examples of the positive electrode active material include materials capable of doping and dedoping lithium ions.

Examples of the material include lithium composite oxides containing at least one transition metal such as V, ti, cr, mn, fe, co, ni, cu. Examples of the lithium composite oxide include lithium-containing transition metal oxides that are solid solutions of lithium composite oxides having a layered structure, lithium composite oxides having a spinel structure, or lithium composite oxides having both a layered structure and a spinel structure. Further, a lithium cobalt composite oxide and a lithium nickel composite oxide may be mentioned. Further, as a part of the transition metal atoms of the lithium composite oxide main body, a material substituted with other elements such as Na, K, B, F, al, ti, V, cr, mn, fe, co, ni, cu, zn, mg, ca, ga, zr, si, nb, mo, sn and W may be mentioned.

Examples of the lithium composite oxide in which a part of the main transition metal atoms of the lithium composite oxide is replaced with another element include a lithium cobalt composite oxide having a layered structure represented by the following formula (5), a lithium nickel composite oxide represented by the following formula (6), a lithium manganese composite oxide having a spinel structure represented by the following formula (7), a solid solution lithium-containing transition metal oxide represented by the following formula (8), and the like.

Li[Li _x (Co _1-a M ¹ _a ) _1-x ]O ₂ Formula (5)

(in the formula (5), M ¹ Is at least 1 metal selected from Na, K, B, F, al, ti, V, cr, mn, fe, ni, cu, zn, mg, ga, zr, si, nb, mo, sn and W, and satisfies x is more than or equal to-0.1 and less than or equal to 0.30, a is more than or equal to 0 and less than or equal to 0.5. )

Li[Li _y (Ni _1-b M ² _b ) _1-y ]O ₂ Formula (6)

(in formula (6), M ² Is at least 1 metal selected from Na, K, B, F, al, ti, V, cr, mn, fe, co, cu, zn, mg, ga, zr, si, nb, mo, sn and W, and satisfies that y is more than or equal to-0.1 and less than or equal to 0.30, and b is more than or equal to 0 and less than or equal to 0.5. )

Li _z Mn _2-c M ³ _c O ₄ Formula (7)

(in the formula (7), M ³ Is at least 1 metal selected from Na, K, B, F, al, ti, V, cr, fe, co, ni, cu, zn, mg, ga, zr, si, nb, mo, sn and W, and satisfies 0.9.ltoreq.z, 0.ltoreq.c.ltoreq.1.5. )

Li _1+w M ⁴ _d M ⁵ _e O ₂ Formula (8)

(in the formula (8), M ⁴ And M ⁵ Is at least 1 metal in Al, ti, V, cr, mn, fe, co, ni, cu, zn, mg and Ca, and satisfies 0 < w.ltoreq.1/3, 0.ltoreq.d.ltoreq.2/3, 0.ltoreq.e.ltoreq.2/3, w+d+e=1. )

Specific examples of the lithium composite oxides represented by the above formulas (5) to (8) include LiCoO ₂ 、LiNiO ₂ 、LiMnO ₂ 、LiNi _0.8 Co _0.2 O ₂ 、LiNi _0.5 Mn _0.5 O ₂ 、LiNi _0.85 Co _0.10 Al _0.05 O ₂ 、LiNi _0.8 Co _0.15 Al _0.05 O ₂ 、LiNi _0.5 Co _0.2 Mn _0.3 O ₂ 、LiNi _0.6 Co _0.2 Mn _0.2 O ₂ 、LiNi _0.33 Co _0.33 Mn _0.33 O ₂ 、LiMn ₂ O ₄ 、LiMn _1.5 Ni _0.5 O ₄ 、LiMn _1.5 Fe _0.5 O ₄ 、LiCoMnO ₄ 、Li _1.21 Ni _0.20 Mn _0.59 O ₂ 、Li _1.22 Ni _0.20 Mn _0.58 O ₂ 、Li _1.22 Ni _0.15 Co _0.10 Mn _0.53 O ₂ 、Li _1.07 Ni _0.35 Co _0.08 Mn _0.50 O ₂ 、Li _1.07 Ni _0.36 Co _0.08 Mn _0.49 O ₂ Etc.

Further, lithium composite oxides other than the lithium composite oxides represented by the formulas (5) to (8) can be preferably used as the positive electrode active material. Examples of such lithium composite oxides include LiNiVO ₄ 、LiV ₃ O ₆ 、Li _1.2 Fe _0.4 Mn _0.4 O ₂ Etc.

Examples of materials other than the lithium composite oxide that can be preferably used as the positive electrode active material include phosphates having an olivine-type structure, and phosphates having an olivine-type structure represented by the following formula (9).

Li _v (M ⁶ _f M ⁷ _g M ⁸ _h M ⁹ _i ) _j PO ₄ Formula (9)

(in the formula (9), M ⁶ Is Mn, co or Ni, M ⁷ Ti, V, cr, mn, fe, co, ni, zr, nb, or Mo, M ⁸ For transition metals or main group elements other than elements of any group VIA or group VIIA, M ⁹ Is a transition metal or a main group element other than any element of VIA group and VIIA group, and satisfies that 1.2 is more than or equal to 0.9, 1 is more than or equal to 0.6, 0.4 is more than or equal to 0, 0.2 is more than or equal to d is more than or equal to 0, 0.2 is more than or equal to 0, and 1.2 is more than or equal to 0.9. )

The positive electrode active material preferably has a coating layer on the surface of particles of the lithium metal composite oxide constituting the positive electrode active material. Examples of the material constituting the above-mentioned coating layer include metal composite oxides, metal salts, boron-containing compounds, nitrogen-containing compounds, silicon-containing compounds, and sulfur-containing compounds, and among these, metal composite oxides are suitably used.

As the metal composite oxide, an oxide having lithium ion conductivity is preferably used. Examples of the metal composite oxide include a metal composite oxide of Li and at least 1 element selected from Nb, ge, si, P, al, W, ta, ti, S, zr, zn, V and B. When the positive electrode active material has a coating layer, the coating layer can suppress side reactions at the interface between the positive electrode active material and the electrolyte at high voltage, and can achieve a longer lifetime of the secondary battery obtained. In addition, formation of a high-resistance layer at the interface between the positive electrode active material and the electrolyte can be suppressed, and the power of the secondary battery obtained can be increased.

Examples of the conductive agent include carbon materials such as natural graphite, artificial graphite, cokes, carbon black, pyrolytic carbon, carbon fibers, and calcined organic polymer compounds.

Examples of the binder include polyvinylidene fluoride, a copolymer of vinylidene fluoride, polytetrafluoroethylene, a copolymer of vinylidene fluoride and hexafluoropropylene, a copolymer of tetrafluoroethylene and perfluoroalkyl vinyl ether, a copolymer of ethylene and tetrafluoroethylene, a copolymer of vinylidene fluoride and trifluoroethylene, a copolymer of vinylidene fluoride and trichloroethylene, a copolymer of vinylidene fluoride and fluoroethylene, a copolymer of vinylidene fluoride and hexafluoropropylene, a thermoplastic resin such as thermoplastic polyimide, polyethylene and polypropylene, an acrylic resin, and a styrene butadiene rubber. In addition, the binder also has a function as a thickener.

Examples of the positive electrode current collector include a conductor such as Al, ni, and stainless steel. Among them, al is more preferable for the reason of easy processing into a thin film and low cost.

Examples of the method for producing the sheet-like positive electrode include a method in which a positive electrode active material, a conductive agent, and a binder, which are to be positive electrode mixture, are press-molded on a positive electrode current collector; and a method in which the positive electrode active material, the conductive agent, and the binder are made into paste with an appropriate organic solvent to obtain a positive electrode mixture, the positive electrode mixture is applied to a positive electrode current collector, and the sheet-shaped positive electrode mixture obtained by drying the positive electrode mixture is pressed to fix the positive electrode current collector.

[ negative electrode ]

As the negative electrode, for example, a negative electrode sheet having a structure in which an active material layer containing a negative electrode active material and a binder is formed on a current collector can be used. The active material layer may further contain a conductive agent.

Examples of the negative electrode active material include carbon materials, chalcogenides (oxides, sulfides, and the like), nitrides, metals, or alloys, and materials capable of doping/dedoping lithium ions at a lower potential than the positive electrode.

Examples of the carbon material that can be used as the negative electrode active material include graphite such as natural graphite and artificial graphite, cokes, carbon black, pyrolytic carbons, carbon fibers, and calcined organic polymer compounds.

Examples of the oxide that can be used as the negative electrode active material include SiO ₂ SiO, etc. in the form of SiO _x (here, x is a positive real number) represented by silicon oxide; tiO (titanium dioxide) ₂ TiO and the like as TiO _x (here, x is a positive real number) represented by titanium oxide; v (V) ₂ O ₅ 、VO ₂ Equal form V _x O _y (here, x and y are positive real numbers) of vanadium oxide; fe (Fe) ₃ O ₄ 、Fe ₂ O ₃ FeO and the like are represented by Fe _x O _y (where x and y are positive real numbers) and a metal oxide represented by the formula (i); snO (SnO) ₂ Such as SnO _x (where x is a positive real number) and a tin oxide represented by the formula (i); WO (WO) ₃ 、WO ₂ Is of the general formula WO _x (where x is a positive real number) represented by tungsten oxide; li (Li) ₄ Ti ₅ O ₁₂ 、LiVO ₂ And a composite metal oxide containing lithium and containing titanium or vanadium; etc.

Examples of the sulfide that can be used as the negative electrode active material include Ti ₂ S ₃ 、TiS ₂ TiS, etc. of Ti _x S _y (where x and y are positive real numbers) a titanium sulfide represented by the formula (i); v (V) ₃ S ₄ 、VS ₂ VS, etc. by VS _x (where x is a positive real number) a vanadium sulfide represented by the formula; fe (Fe) ₃ S ₄ 、FeS ₂ FeS, etc. of the formula Fe _x S _y (where x and y are positive real numbers) and a metal sulfide represented by the formula (i); mo (Mo) ₂ S ₃ 、MoS ₂ Isomorphic Mo _x S _y (where x and y are positive real numbers) molybdenum sulfide; snS (SnS) ₂ SnS, etc. is SnS _x (where x is a positive real number) a tin sulfide represented by the formula (i); WS (WS) ₂ Iso WS _x (where x is a positive real number) a tungsten sulfide represented by the formula (i); sb (Sb) ₂ S ₃ Isotopy type Sb _x S _y (where x and y are positive real numbers) and a method for producing the same; se (Se) ₅ S ₃ 、SeS ₂ SeS, etc. of Se _x S _y (where x and y are positive real numbers) and a selenium sulfide represented by the formula (i).

Examples of the nitride that can be used as the negative electrode active material include Li ₃ N、Li _3-x A _x N (where A is either or both of Ni and Co, 0 < x < 3.) and the like.

These carbon materials, oxides, sulfides, and nitrides may be used singly or in combination. These carbon materials, oxides, sulfides, and nitrides may be crystalline or amorphous. These carbon materials, oxides, sulfides, and nitrides are mainly supported on the negative electrode current collector and used as electrodes.

Examples of the metal that can be used as the negative electrode active material include metallic lithium, metallic silicon, and metallic tin.

Further, a composite material containing Si or Sn as the 1 st constituent element and further containing the 2 nd and 3 rd constituent elements is exemplified. The 2 nd constituent element is at least 1 of cobalt, iron, magnesium, titanium, vanadium, chromium, manganese, nickel, copper, zinc, gallium, and zirconium, for example. The 3 rd constituent element is, for example, at least 1 of boron, carbon, aluminum, and phosphorus.

In particular, from the viewpoint of obtaining a high battery capacity and excellent battery characteristics, a single piece of silicon or tin is preferable as the above-mentioned metal material Mass (may contain trace amounts of impurities), siO _v (0＜v≤2)、SnO _w (w is more than or equal to 0 and less than or equal to 2), si-Co-C composite material, si-Ni-C composite material, sn-Co-C composite material and Sn-Ni-C composite material.

Examples of the negative electrode current collector include Cu, ni, and stainless steel. Among them, cu is more preferable for the reason that it is difficult to alloy with lithium and it is easy to process into a thin film, particularly in a lithium ion secondary battery.

Examples of the method for producing a sheet-like negative electrode include a method in which a negative electrode active material serving as a negative electrode mixture is press-molded on a negative electrode current collector; and a method in which the negative electrode active material is made into a paste by using an appropriate organic solvent to obtain a negative electrode mixture, the negative electrode mixture is applied to a negative electrode current collector, and the sheet-shaped negative electrode mixture obtained by drying the negative electrode mixture is pressed and fixed to the negative electrode current collector. The paste preferably contains the conductive agent and the binder.

[ nonaqueous electrolyte solution ]

As the nonaqueous electrolytic solution, for example, a nonaqueous electrolytic solution obtained by dissolving a lithium salt in an organic solvent can be used. Examples of the lithium salt include LiClO ₄ 、LiPF ₆ 、LiAsF ₆ 、LiSbF ₆ 、LiBF ₄ 、LiSO ₃ F、LiCF ₃ SO ₃ 、LiN(SO ₂ CF ₃ ) ₂ 、LiN(SO ₂ C ₂ F ₅ ) ₂ 、LiN(SO ₂ CF ₃ )(COCF ₃ )、Li(C ₄ F ₉ SO ₃ )、LiC(SO ₂ CF ₃ ) ₃ 、Li ₂ B ₁₀ Cl ₁₀ LiBOB (BOB here means bis (oxalato) borate), lithium salts of lower aliphatic carboxylic acids, liAlCl ₄ Etc. These may be used alone or as a mixture of 2 or more. Among them, as the lithium salt, a lithium salt containing a fluorine-containing LiPF is preferably used ₆ 、LiAsF ₆ 、LiSbF ₆ 、LiBF ₄ 、LiSO ₃ F、LiCF ₃ SO ₃ 、LiN(SO ₂ CF ₃ ) ₂ And LiC (SO) ₂ CF ₃ ) ₃ At least 1 lithium salt of (b).

Examples of the organic solvent include carbonates such as propylene carbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate, methylethyl carbonate, 4-trifluoromethyl-1, 3-dioxolan-2-one, and 1, 2-bis (methoxycarbonyloxy) ethane; ethers such as 1, 2-dimethoxyethane, 1, 3-dimethoxypropane, pentafluoropropyl methyl ether, 2, 3-tetrafluoropropyl difluoromethyl ether, tetrahydrofuran, and 2-methyltetrahydrofuran; esters such as methyl formate, methyl acetate, and γ -butyrolactone; nitriles such as acetonitrile and butyronitrile; amides such as N, N-dimethylformamide and N, N-dimethylacetamide; carbamates such as 3-methyl-2-oxazolidinone; sulfur-containing compounds such as sulfolane, dimethyl sulfoxide, and 1, 3-propane sultone; or a solvent in which a fluorine group is further introduced into the organic solvent (in which 1 or more hydrogen atoms are substituted with fluorine atoms).

The organic solvent is preferably used by mixing 2 or more kinds of organic solvents as a mixed solvent. Among them, a mixed solvent containing carbonates is preferable, and a mixed solvent of a cyclic carbonate and a non-cyclic carbonate and a mixed solvent of a cyclic carbonate and an ether are more preferable. As the mixed solvent of the cyclic carbonate and the acyclic carbonate, a mixed solvent containing ethylene carbonate, dimethyl carbonate and ethylmethyl carbonate is preferable. The nonaqueous electrolyte solution using such a mixed solvent has advantages in that the working temperature range is wide, degradation is difficult even when used under high voltage, degradation is difficult even when used for a long period of time, and decomposition is difficult when a graphite material such as natural graphite or artificial graphite is used as a negative electrode active material.

In addition, as the nonaqueous electrolyte solution, liPF-containing secondary batteries are preferably used in order to improve the safety of the obtained nonaqueous electrolyte solution secondary batteries ₆ And a fluorine-containing lithium salt and a fluorine-substituted organic solvent. Since the capacity retention rate is high even when the electric discharge is performed at a high voltage, a mixed solvent of ethers having a fluorine substituent such as pentafluoropropyl methyl ether and 2, 3-tetrafluoropropyl difluoromethyl ether and dimethyl carbonate is more preferable.

[ Member for nonaqueous electrolyte secondary battery and method for producing nonaqueous electrolyte secondary battery ]

Examples of the method for producing the member for a nonaqueous electrolyte secondary battery include a method in which a positive electrode, a laminated separator for a nonaqueous electrolyte secondary battery according to one embodiment of the present invention, and a negative electrode are arranged in this order.

The nonaqueous electrolyte secondary battery can be produced by the following method, for example. First, the nonaqueous electrolyte secondary battery member is placed in a container serving as a nonaqueous electrolyte secondary battery case. Then, after the inside of the container was filled with the nonaqueous electrolyte, the container was sealed while the pressure was reduced. Thus, a nonaqueous electrolyte secondary battery can be manufactured.

The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims, and embodiments obtained by appropriately combining the technical means disclosed in the different embodiments are also included in the technical scope of the present invention.

[ example ]

Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited to these examples.

[ method for measuring various physical Properties ]

The resin having an amide bond and a bond other than an amide bond, the porous layer, and the laminated separator having the non-porous layer, and the like, which are prepared in examples and comparative examples described below, were measured for various physical properties by the methods described below.

[ film thickness ]

The film thickness of the laminated separator and porous film was measured using a high-precision digital Length measuring machine (VL-50) manufactured by Sanfeng, inc. Further, the difference between the film thickness of the laminated separator and the film thickness of the porous film was calculated as the film thickness of the porous layer.

[ gram weight ]

From the porous films used in examples and comparative examples described later, a square sample having a length of 8cm was cut out on one side, and the weight W (g) of the sample was measured. Then, the grammage of the porous film was calculated according to the following formula (10).

Gram weight (g/m) of porous film ² ) =w/(0.08×0.08) (10)

Similarly, a square sample having a length of 8cm was cut out of the laminated separator, and the weight W (g) of the sample was measured. Next, the grammage of the laminated separator is calculated according to the following formula (11).

Gram weight (g/m) of laminated separator ² ) =w/(0.08×0.08) type (11)

Using the grammage of the laminated separator and the grammage of the porous film, the grammage of the porous layer was calculated according to the following formula (12).

Gram weight (g/m) of porous layer ² ) = (grammage of laminated separator) - (grammage of porous film) (12)

[ air permeability ]

The air permeability (gurley number) of the laminated separator and the air permeability of the laminated separator after the porous layer was peeled off were measured in accordance with JIS P8117.

[ intrinsic viscosity ]

The intrinsic viscosity was measured by the following measurement method.

The flow time at 30℃was measured with a capillary viscometer for 100mL of a solution of 0.5g of the polymer to be measured dissolved in 96-98% sulfuric acid and 96-98% sulfuric acid, respectively. From the measured flow time, the intrinsic viscosity was determined according to the following formula.

Intrinsic viscosity=ln (T/T0)/C [ unit: dL/g ]

T: flow time of sulfuric acid solution of polymer

T0: flow time of sulfuric acid

C: polymer concentration in solution (g/dL).

Peak ratio

The peak ratio represented by "formula (1)" of the laminated separator was calculated by a method comprising the following steps (i) to (v).

(i) The surfaces of the polyolefin porous films used in examples, comparative examples and reference examples on which porous layers were laminated were subjected to measurement by the ATR method using a reflection type infrared analyzer (trade name: cary 660FTIR, manufactured by agilent corporation) to obtain IR spectra.

(ii) The step of obtaining an IR spectrum by measuring the surface of the laminated separator on the opposite side of the porous layer using the reflection type infrared analyzer used in the step (i) by the ATR method is performed.

(iii) A step of obtaining "measured peak intensity A" and "peak intensity B" based on the IR spectrum obtained in step (ii), and a step of obtaining "base peak intensity A" based on the IR spectrum obtained in step (i).

(iv) And (3) calculating a peak ratio represented by the following formula (1') using the "measured peak intensity a", "base peak intensity a", and "peak intensity B" obtained in the step (iii).

In the steps (i) and (ii), measurement conditions for obtaining an IR spectrum by the ATR method are as follows.

[ IR measurement ]

In the step (iii), specifically, the IR spectrum obtained in the step (ii) is measured to be present at 1570cm in wave number ^-1 ～1620cm ^-1 The peak intensity in the range of (2) was regarded as "measured peak intensity A", and the peak intensity A was measured to be present at a wave number of 1450cm ^-1 ～1550cm ^-1 The peak intensity of the range of (B) is referred to as "peak intensity B". In addition, the IR spectrum obtained in the measurement step (i) was found to be at 1570cm in wavenumber ^-1 ～1620cm ^-1 The peak intensity of the range of (2) is defined as "base peak intensity A".

[ endless belt windability ]

The diaphragm parent roll is cut into a fixed width (65 mm-68 mm) by slitting, and a sample is prepared. The laminated separator was transported at a speed of 100 m/min, and the roll was replaced. In the case of roll replacement, whether the winding of the endless belt of the laminated separator was performed well was evaluated based on < evaluation criterion > shown below.

< evaluation criterion >

Good: the occurrence ratio of the visually distinguishable winding deviations was 10% or less.

The method is not good: the occurrence ratio of the visually distinguishable winding deviations was 10% or more.

Example 1

< preparation of composition >

A composition was prepared by a method comprising the steps shown in the following (a) to (g).

(a) The 5L split flask with stirring vanes, thermometer, nitrogen inflow tube and powder addition port was sufficiently dried.

(b) 4217g of N-methylpyrrolidone (NMP) was added to the flask. Further, 324.22g of calcium chloride (dried at 200℃for 2 hours) was added and heated to 100℃to completely dissolve the calcium chloride, thereby obtaining a calcium chloride solution. In the calcium chloride solution, the concentration of calcium chloride was adjusted to 7.14 wt% and the water content was adjusted to 300ppm.

(c) To the above calcium chloride solution, 140.816g of 4,4' -diaminodiphenyl sulfone (DDS) was added while maintaining its temperature at 100℃to completely dissolve, thereby obtaining solution A (1).

(d) The resulting solution A (1) was cooled to 25 ℃. Then, as to the cooled solution A (1), a total of 114.564g of terephthaloyl chloride (TPC) was added in 3 portions while maintaining the temperature at 25℃and reacted for 1 hour to obtain a reaction solution A (1). Feed ratio in reaction solution a (1): the molar ratio of DDS/TPC added to solution A (1) was 1.005. In the reaction solution A (1), a block A (1) composed of poly (4, 4' -diphenylsulfonyl terephthalamide) was produced.

(e) To the resulting reaction solution A (1), 61.328g of p-phenylenediamine (PPD) was added, and it took 1 hour to completely dissolve, to obtain a solution B (1).

(f) As to the solution B (1), 114.335g of TPC was added in total in 3 portions while maintaining the temperature at 25℃and reacted for 1.5 hours to obtain a reaction solution B (1). Feed ratio in reaction solution B (1): the molar ratio of PPD/TPC added to solution B was 1.007. In the reaction solution B (1), a block B (1) composed of poly (paraphenylene terephthalamide) is grown on both sides of the block A (1).

(g) The aging was performed for 1 hour while maintaining the temperature of the reaction solution B (1) at 25 ℃. Then, the mixture was stirred under reduced pressure for 1 hour to remove bubbles. As a result, a solution of the block copolymer (1) containing 50% of the entire molecule of the block A (1) and the remaining 50% of the entire molecule of the block B (1) was obtained. The block copolymer (1) is a resin having an amide bond and a bond other than the amide bond.

To another flask different from the above-mentioned separate flask, 0.5L of ion exchange water was added. Further, 50mL of a solution containing the block copolymer (1) was measured. Then, 50mL of the solution containing the block copolymer (1) was added to the other flask, and the block copolymer (1) was precipitated. The block copolymer (1) thus precipitated was subjected to filtration treatment, whereby it was separated to obtain a composition (1) composed of 3.5g of the block copolymer (1). In the filtration treatment, the solution in which the block copolymer (1) was precipitated was filtered 1 time, and 100mL of ion-exchanged water was added to the obtained precipitate, followed by further filtration. I.e. 2 times. Using the obtained composition (1), the intrinsic viscosity was measured and found to be 2.08dL/g.

< preparation of porous layer, laminated separator >

To 4000g of a solution containing the block copolymer (1), 6.83L of NMP was added to obtain a solution in which the block copolymer (1) was dissolved and dispersed. To a solution in which the above block copolymer (1) was dissolved and dispersed, 280.0g of alumina (average particle diameter: 0.013 μm) was added. The obtained mixture was uniformly dispersed by a pressure type dispersing machine to prepare a coating liquid. The solid content concentration of the coating liquid was 5 wt%.

The coating liquid was applied to a polyethylene porous film (thickness: 9.9 μm, gram weight: 5.7 g/m) ² ) The porous layer was formed by treatment in an oven at 50 ℃ and a humidity of 70% for 2 minutes. Then, the porous layer is washed with water and dried to obtain a laminated separator (1).

Example 2

Except that in the steps (d) to (g), the temperatures of the solution a (2), the reaction solution a (2), the solution B (2) and the reaction solution B (2) were changed to 20 ℃; in the step (d), the amount of TPC used was changed so that the feed ratio in the reaction solution a (2) was 1.0083; and in the step (f), a composition (2) comprising a solution of the block copolymer (2) in which the block A (2) represents 50% of the entire molecule and the block B (2) represents the remaining 50% of the entire molecule and 3.5g of the block copolymer (2) was obtained in the same manner as in example 1 except that the amount of TPC used was changed so that the feed ratio in the reaction solution B (2) was 1.0099. As a result of the above-mentioned intrinsic viscosity measurement, the block copolymer (2) had an intrinsic viscosity of 1.64dL/g, using the obtained composition (2). The block copolymer (2) is a resin having an amide bond and a bond other than the amide bond.

Except that the solution containing the block copolymer (2) was used instead of the solution containing the block copolymer (1), and as the polyethylene porous film, a polyethylene porous film (thickness: 10.5 μm, gram weight: 5.8g/m ² ) Except for the above, a laminated separator (2) was obtained in the same manner as in example 1.

Example 3

A laminated separator (3) was obtained in the same manner as in example 2, except that the same polyolefin porous film as in example 1 was used as the polyolefin porous film.

Example 4

A laminated separator (4) was obtained in the same manner as in example 3, except that the oven treatment time at the time of forming the porous layer was set to 1 minute.

Example 5

Except that in the step (b), the amount of NMP used was changed to 4177g, the amount of calcium chloride used was changed to 366.29g, and the water content was adjusted to 400ppm; in the step (d), the amount of TPC used was changed so that the feed ratio in the reaction solution A (3) was 1.011; and in the step (f), a composition (3) comprising a block copolymer (3) having 50% of the block A (3) and the remaining 50% of the block B (3) as a whole and 3.5g of the block copolymer (3) was obtained in the same manner as in example 2, except that the amount of TPC used was changed so that the feed ratio in the reaction solution B (3) was 1.013. As a result of the above-mentioned intrinsic viscosity measurement using the obtained composition (3), the intrinsic viscosity of the block copolymer (3) was 1.65dL/g. The block copolymer (3) is a resin having an amide bond and a bond other than the amide bond.

A laminated separator (5) was obtained in the same manner as in example 3, except that a solution containing the block copolymer (3) was used instead of the solution containing the block copolymer (2).

Example 6

Except that in the step (b), the amount of NMP used was changed to 4177g, the amount of calcium chloride used was changed to 366.29g, and the water content was adjusted to 320ppm; in the step (d), the amount of TPC used was changed so that the ratio of the reaction solution A (4) to the feed was 1.016; and in the step (f), a composition (4) comprising a block copolymer (4) in which the block A (4) was 50% of the entire molecule and the block B (4) was the remaining 50% of the entire molecule, and 3.5g of the block copolymer (4) was obtained in the same manner as in example 1 except that the amount of TPC used was changed so that the feed ratio in the reaction solution B (4) was 1.018. As a result of the above-mentioned intrinsic viscosity measurement using the obtained composition (4), the intrinsic viscosity of the block copolymer (4) was 1.57dL/g. The block copolymer (4) is a resin having an amide bond and a bond other than the amide bond.

A laminated separator (6) was obtained in the same manner as in example 3, except that a solution containing the block copolymer (4) was used instead of the solution containing the block copolymer (2).

Example 7

A laminated separator (7) was obtained in the same manner as in example 6, except that the same polyolefin porous film as in example 1 was used as the polyolefin porous film.

Example 8

Except for using a polyolefin porous film (thickness: 10.0 μm, gram weight: 6.1 g/m) different from examples 1 to 7 as the polyolefin porous film ² ) A laminated separator (8) was obtained in the same manner as in example 6.

Example 9

A composition (5) comprising a block copolymer (5) solution containing 40% of the entire molecule of the block A (5) and 60% of the entire molecule of the block B (5) and 3.5g of the block copolymer (5) was obtained in the same manner as in example 2, except that the amount of NMP used in the step (B) was changed to 4177g, the amount of calcium chloride used in the step (c) was changed to 366.29g, the amount of DDS used in the step (c) was changed to 118.744g, the amount of TPC used in the step (d) was changed to 95.093g, the amount of PPD used in the step (e) was changed to 77.573g and the amount of TPC used in the step (f) was changed to 142.361 g. As a result of the above-mentioned intrinsic viscosity measurement using the obtained composition (5), the intrinsic viscosity of the block copolymer (5) was 1.57dL/g. The block copolymer (5) is a resin having an amide bond and a bond other than the amide bond.

A laminated separator (9) was obtained in the same manner as in example 8, except that the block copolymer (5) was used in place of the block copolymer (4).

Example 10

A composition (6) comprising a solution of a block copolymer (6) in which the block A (6) was present in an amount of 30% of the whole molecule and the block B (6) was present in an amount of 70% of the whole molecule, and 3.0g of the block copolymer (6) was obtained in the same manner as in example 2, except that the amount of DDS used in the step (c) was changed to 79.160g, the amount of TPC used in the step (d) was changed to 63.207g, the amount of PPD used in the step (e) was changed to 80.443g, and the amount of TPC used in the step (f) was changed to 147.772 g. As a result of carrying out the above-mentioned intrinsic viscosity measurement using the obtained composition (6), the intrinsic viscosity was 1.36dL/g. The block copolymer (6) is a resin having an amide bond and a bond other than the amide bond.

A laminated separator (10) was obtained in the same manner as in example 9, except that instead of containing the block copolymer (5), a solution containing the block copolymer (6) was used, and the amount of NMP used was changed to 5.18L and the amount of alumina (average particle diameter: 0.013 μm) used was changed to 240.0 g.

Example 11

A composition (7) composed of a block copolymer (7) containing 20% of the above block a (7) and 80% of the rest of the block B (7) as a whole was obtained in the same manner as in example 1, except that the water content was adjusted to 320ppm in the step (B), the DDS usage amount in the step (c) was changed to 55.727g, the TPC usage amount in the step (d) was changed to 44.324g, the PPD usage amount in the step (e) was changed to 97.081g, and the TPC usage amount in the step (f) was changed to 177.640g, respectively. As a result of carrying out the above-mentioned intrinsic viscosity measurement using the obtained composition (7), the intrinsic viscosity was 1.47dL/g. The block copolymer (7) is a resin having an amide bond and a bond other than the amide bond.

A laminated separator (11) was obtained in the same manner as in example 10, except that the solution containing the block copolymer (7) was used instead of the solution containing the block copolymer (6).

Example 12

To 4000g of the above-mentioned solution containing the block copolymer (4), 9.44L of NMP was added to obtain a solution in which the above-mentioned block copolymer (4) was dissolved and dispersed. To a solution in which the block copolymer (4) was dissolved and dispersed, 280.0g of alumina (average particle diameter: 0.013 μm) and 350.0g of alumina having a larger particle diameter (average particle diameter: 0.7 μm) were added. The obtained mixture was uniformly dispersed by a pressure type dispersing machine to prepare a coating liquid. The solid content concentration of the coating liquid was 6 wt%. Using the coating liquid, a laminated separator (12) was obtained in the same manner as in example 8.

Comparative example 1

A comparative composition (1) was obtained in the same manner as in example 1 except that in the step (B), the water content was adjusted to 1000ppm, and that the composition contained 50% of the comparative polymer (1) in which the comparative block A (1) was the entire molecule and 50% of the remaining 50% of the comparative block B (1) was the entire molecule, and 3.50g of the comparative polymer (1) was composed. Using the comparative composition (1), the intrinsic viscosity was measured and found to be 1.08dL/g. The comparative polymer (1) is a resin having an amide bond and a bond other than the amide bond.

A laminated separator (1) for comparison was obtained in the same manner as in example 1, except that instead of the solution containing the block copolymer (1), a solution containing the comparative polymer (1) was used, and 7.61L of NMP and 300g of alumina (average particle diameter: 0.013 μm) were used.

Comparative example 2

In the same manner as in example 1 except that the water content was adjusted to 1000ppm in the step (B), and the temperatures of the comparative solution A (2), the comparative reaction solution B (2) and the comparative reaction solution B (2) corresponding to the solution A, the reaction solution A, the solution B and the reaction solution B in the steps (d) to (g) were changed to 40 ℃, a solution of the comparative polymer (2) comprising 50% of the comparative block A (2) and 50% of the residual comparative block B (2) and a comparative composition (2) composed of 3.5g of the comparative polymer (2) were obtained. Using the comparative composition (2), the intrinsic viscosity was measured and found to be 1.14dL/g. The comparative polymer (2) is a resin having an amide bond and a bond other than the amide bond.

A laminated separator (2) for comparison was obtained in the same manner as in example 1, except that a solution containing the comparative polymer (2) was used instead of the solution containing the block copolymer (1).

Comparative example 3

In the same manner as in example 1 except that the water content was adjusted to 500ppm in the step (B), and the temperatures of the comparative solution A (3), the comparative reaction solution B (3), and the comparative reaction solution B (3) corresponding to the solution A, the reaction solution A, the solution B, and the reaction solution B in the steps (d) to (g) were changed to 60 ℃, a comparative composition (3) comprising a comparative polymer (3) in which the comparative block A (3) was 50% of the entire molecule, the comparative block B (3) was the remaining 50% of the entire molecule, and 3.5g of the comparative polymer (3) was obtained. Using the comparative composition (3), the intrinsic viscosity was measured and found to be 1.15dL/g. The comparative polymer (3) is a resin having an amide bond and a bond other than the amide bond.

A laminated separator (3) for comparison was obtained in the same manner as in example 1, except that a solution containing the comparative polymer (3) was used instead of the solution containing the block copolymer (1).

Comparative example 4

A comparative composition (4) was obtained in the same manner as in example 1, except that in the step (B), the water content was adjusted to 760ppm, and a solution of the comparative polymer (4) comprising 50% of the entire molecule of the comparative block A (4), 50% of the entire molecule of the comparative block B (4), and 3.5g of the comparative polymer (4) was obtained. Using the comparative composition (4), the intrinsic viscosity was measured and found to be 1.01dL/g. The comparative polymer (4) is a resin having an amide bond and a bond other than the amide bond.

A laminated separator (4) for comparison was obtained in the same manner as in example 1, except that a solution containing the comparative polymer (4) was used instead of the solution containing the block copolymer (1).

Comparative example 5

Synthesis example 1

Step (a') was performed to sufficiently dry a 5L split flask equipped with a stirring blade, a thermometer, a nitrogen inflow tube, and a powder addition port.

Step (b') to the flask was added 4089g of NMP. Further, 314.4g of calcium chloride (dried at 200℃for 2 hours) was added, and the temperature was raised to 100℃to completely dissolve the calcium chloride, thereby obtaining a calcium chloride solution. In the calcium chloride solution, the concentration of calcium chloride was adjusted to 7.14 wt% and the water content was adjusted to 500ppm.

Step (c') to the above calcium chloride solution, 329.281g of DDS was added while maintaining the temperature at 100℃to completely dissolve the solution, thereby obtaining a comparative solution A (5).

Step (d') the obtained comparative solution A (5) was cooled to 20 ℃. Then, as to the cooled comparative solution A (5), a total of 266.568g of terephthaloyl chloride (TPC) was added three times while maintaining the temperature at 20.+ -. 2 ℃ and reacted for 1 hour to obtain comparative reaction solution A (5).

Step (e') aging was performed for 1 hour while maintaining the temperature of the comparative reaction solution A (5) at 20.+ -. 2 ℃. Then, the mixture was stirred under reduced pressure for 1 hour to remove bubbles. As a result, a solution containing a comparative polymer (5) consisting of poly (4, 4' -diphenylsulfonyl terephthalamide) was obtained.

To another flask different from the above-mentioned separate flask, 0.5L of ion exchange water was added. Further, 50mL of a solution containing the above comparative polymer (5) was measured. Then, 50mL of the solution containing the comparative polymer (5) was added to the other flask, and the comparative polymer (5) was precipitated. The precipitated comparative polymer (5) was subjected to filtration treatment and separated to obtain 5.0g of the comparative composition (5) composed of the comparative polymer (5). In the above-mentioned filtration treatment, the solution in which the comparative polymer (5) was precipitated was filtered 1 time, and 100mL of ion-exchanged water was added to the obtained precipitate, followed by further filtration. I.e. 2 times. As a result of carrying out the above-mentioned intrinsic viscosity measurement using the comparative composition (5), the intrinsic viscosity was 0.85dL/g.

Synthesis example 2

A solution containing a comparative polymer (6) composed of poly (paraphenylene terephthalamide) was obtained in the same manner as in example 1, except that the amount of NMP used in step (b ') was changed to 4280g, the amount of calcium chloride was changed to 329.1g, the temperature of the calcium chloride solution in step (c ') was adjusted to 30 ℃, PPD was used instead of DDS, the amount of PPD was changed to 138.57g, and the amount of TPC used in step (d ') was changed to 252.06 g. Comparative composition (6) was obtained in the same manner as in Synthesis example 1, except that a solution containing comparative polymer (6) was used instead of containing comparative polymer (1). As a result of carrying out the above-mentioned intrinsic viscosity measurement using the comparative composition (6), the intrinsic viscosity was 1.90dL/g.

Comparative polymer (5) was prepared: the weight ratio of the comparative polymer (6) was 50: 50. Specifically, the polymerization liquids synthesized in synthesis examples 1 and 2 were mixed so that the comparative polymer (5): the weight ratio of the comparative polymer (6) was 50:50 g of a mixed solution was obtained. A laminated separator was obtained in the same manner as in example 2, except that 4000g of the above-mentioned mixed solution was used in place of 5000g of the solution containing the block copolymer (2), and the amount of used of NMP was changed to 7.61L and the amount of used of alumina (average particle diameter: 0.013 μm) was changed to 300.0 g.

Reference example

The composition was prepared by a method comprising the steps shown in the following (a ') to (e').

(a') A5L split flask having a stirring blade, a thermometer, a nitrogen inflow tube, and a powder addition port was sufficiently dried.

(b') to the flask was added 4280g of NMP. Further, 329.1g of calcium chloride (dried at 200℃for 2 hours) was added, and the temperature was raised to 100℃to completely dissolve the calcium chloride, thereby obtaining a calcium chloride solution. In the calcium chloride solution, the concentration of calcium chloride was adjusted to 7.14 wt% and the water content was adjusted to 500ppm.

(c') to the above calcium chloride solution, 138.932g of PPD was added while maintaining the temperature at 30.+ -. 2 ℃ to be completely dissolved, to obtain a reference solution A.

(d') the obtained reference solution A was cooled to 20 ℃. Then, as to the cooled reference solution A, a total of 251.499g of terephthaloyl chloride (TPC) was added three times while maintaining the temperature thereof at 20.+ -. 2 ℃ and reacted for 1 hour to obtain a reference reaction solution A.

(e') aging was performed for 1 hour while maintaining the temperature of the reference reaction solution A at 20.+ -. 2 ℃. Then, the mixture was stirred under reduced pressure for 1 hour to remove bubbles. The result is a solution comprising a reference polymer consisting of poly (paraphenylene terephthalamide). The reference polymer is a resin having an amide bond.

To another flask different from the above-mentioned separate flask, 0.5L of ion exchange water was added. Then, a solution containing the reference polymer was added to the other flask to precipitate the reference polymer. The precipitated reference polymer was isolated by filtration to obtain 3g of a reference composition composed of the reference polymer. In the filtration treatment, the solution in which the reference polymer was precipitated was filtered 1 time, and 100mL of ion exchange water was added to the obtained precipitate, followed by further filtration. I.e. 2 times. As a result of carrying out the above-mentioned intrinsic viscosity measurement using the reference composition, the intrinsic viscosity was 1.90dL/g.

A laminated separator was obtained in the same manner as in example 1, except that instead of the solution containing the block copolymer (1), a solution containing the reference polymer was used, and the amount of NMP used was changed to 6.34L and the amount of alumina (average particle diameter: 0.013 μm) used was changed to 240.0 g.

Results (results)

The physical properties of the resins (resins having amide bonds and bonds other than amide bonds) constituting the porous layers, the porous layers and the laminated separator, and the endless belt windability of the laminated separator, which were produced in examples 1 to 12 and comparative examples 1 to 5, were measured and evaluated by the above-described methods, and the results thereof are shown in tables 1 and 2 below.

[ Table 1 ]

[ Table 2 ]

Conclusion (S)

As shown in table 2, the peak ratio "represented by the above formula (1) of the laminated separators (1) to (12) of examples 1 to 12 was less than 0.02, while the peak ratio" represented by the above formula (1) of the comparative laminated separators (1) to (5) of comparative examples 1 to 5 was 0.02 or more.

The laminated separators (1) to (12) described in examples 1 to 12 were satisfactory in endless belt winding property, but the comparative laminated separators (1) to (5) described in comparative examples 1 to 5 were inferior in endless belt winding property.

Further, in the laminated separator for reference described in reference example, the peak ratio represented by the above formula (1) was also less than 0.02, and the endless belt winding property was good.

As described above, the laminated separator according to one embodiment of the present invention has a peak ratio represented by the above formula (1) of less than 0.02, and thus exhibits an effect of excellent hoop winding performance and suppressing occurrence of meandering and winding displacement when winding is performed at the time of slitting and at the time of battery assembly.

[ Industrial availability ]

The laminated separator according to one embodiment of the present invention is used for manufacturing a nonaqueous electrolyte secondary battery capable of suppressing occurrence of meandering and winding misalignment of the laminated separator during assembly.

Claims

1. A laminated separator for a nonaqueous electrolyte secondary battery, wherein a porous layer is laminated on one surface of a polyolefin porous film,

the peak ratio represented by the following formula (1) is less than 0.02,

peak ratio=peak intensity a/peak intensity B (1)

In the formula (1), the peak intensity a is the intensity of a peak derived from the amide bond and a bond other than the amide bond in an IR spectrum measured by an ATR method with respect to a surface opposite to a surface on which the porous layer is laminated of the polyolefin porous film; the peak intensity B is the intensity of the peak in the IR spectrum derived from the bonds in the polyolefin porous membrane.

2. The laminated separator for a nonaqueous electrolyte secondary battery according to claim 1,

the peak intensity A in the formula (1) is a value existing in 1570cm of wavenumber in an IR spectrum measured by the ATR method with respect to a surface of the polyolefin porous film opposite to a surface on which the porous layer is laminated ^-1 ～1620cm ^-1 Intensity of peaks in the range of (2);

the peak intensity B in the formula (1) is that in the IR spectrum, it exists at 1450cm wave number ^-1 ～1550cm ^-1 Intensity of peaks in the range of (2).

3. The laminated separator for a nonaqueous electrolyte secondary battery according to claim 1,

at least one of the resins having an amide bond and a bond other than an amide bond is a resin having: a block copolymer comprising a block A having a unit represented by the following formula (2) as a main component and a block B having a unit represented by the following formula (3) as a main component;

-(NH-Ar ¹ -NHCO-Ar ² -CO) -type (2)

-(NH-Ar ³ -NHCO-Ar ⁴ -CO) -type (3)

In the formulas (2) and (3),

All Ar ¹ And Ar is a group ³ 10 to 70% of the aromatic hydrocarbon compounds have a structure in which 2 aromatic rings are linked by sulfonyl bonds.

4. The laminated separator for a nonaqueous electrolyte secondary battery according to any one of claim 1 to 3,

the porous layer further comprises a filler material,

the filler is contained in an amount of 20 to 90 wt% based on the weight of the entire porous layer.

5. A member for a nonaqueous electrolyte secondary battery, wherein a positive electrode, the laminated separator for a nonaqueous electrolyte secondary battery according to any one of claims 1 to 4, and a negative electrode are sequentially arranged.

6. A nonaqueous electrolyte secondary battery comprising the laminated separator for nonaqueous electrolyte secondary batteries according to any one of claims 1 to 4.