JPH10154499A - Separator for battery and non-aqueous secondary battery using thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a separator for a battery which does not have locally abnormal low resistance value between a cathode material and an anode material of a battery. SOLUTION: To produce a separator of a polyolefin porous membrane by making a polyolefin film porous by extrusion of the polyolefin film, the charged voltage, which is a characteristic property of being charged of the separator measured at unspecified points, is adjusted so as to be constantly within ±1kV, by kneading the polyolefin (raw material) with an anti-charging agent or applying or spraying an anti-charging agent to the film (the porous membrane) after extrusion. Consequently, a large local resistance value decrease of the separator due to the adhesion of conductive fine particles of active material particles, which are dropped from the cathode material and the anode material, for the separator is prevented in the battery manufacturing process.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a battery separator and a non-aqueous secondary battery using the same.

[0002]

2. Description of the Related Art Various types of batteries have been put to practical use, and porous or non-porous films, nonwoven fabrics, papers, and the like suitable for the respective types have been proposed as battery separators (hereinafter, also simply referred to as separators). Have been. These battery separators are required to have an affinity (wetting property) with an electrolytic solution and a liquid retaining property, a low electric resistance value, a high air permeability, a high mechanical strength, a chemical stability, and the like. Among these, the affinity and liquid retention of the electrolyte, low electric resistance, high air permeability, etc. are related to the discharge characteristics of the battery and are required to facilitate the movement of ions moving in the battery reaction. It is. The mechanical strength is related to the assembling process of the battery and the subsequent breakage or penetration failure of the separator, and the higher this is, the more the occurrence of internal short circuit failure can be reduced. Since the battery separator is exposed to the oxidizing and reducing atmosphere inside the battery, it is necessary to use a chemically stable material that does not easily decompose or react, and from this viewpoint, polyolefin or fluorine-based polymer must be used. There are many.

[0003] In recent years, non-aqueous secondary batteries, particularly lithium secondary batteries, have attracted attention as batteries for responding to cordless electronic devices due to their high energy density, high electromotive force, and low self-discharge. I'm taking a bath.

A positive electrode material and a negative electrode material in a non-aqueous secondary battery are generally formed by supporting an active material on the surface of an electrode material main body, that is, a metal foil as a current collector. For example, as a negative electrode material of a lithium secondary battery, for example, lithium simple particles, alloy particles of lithium and a metal such as aluminum, particles of a material that adsorbs or occludes lithium ions such as carbon and graphite, or lithium There is known a material in which particles of a conductive polymer material doped with ions are attached as an active material. As the positive electrode material, for example, fluorinated graphite particles represented by a composition formula of (CF) _n , CoLiO ₂ , MnO ₂ , V ₂
Metal oxide particles such as O ₅ , CuO, Ag ₂ CrO ₄ ,
It is known that sulfide particles such as TiO ₂ and CuS are attached as an active material. In addition, a mixed organic solvent such as ethylene carbonate, propylene carbonate, diethyl carbonate, and 1,2-dimethoxyethane is used as the electrolytic solution.

In such a lithium secondary battery, lithium as an active material of a negative electrode material has strong reactivity, and ethylene carbonate, propylene carbonate, acetonitrile, γ-butyl lactone, 1,2-dimethoxyethane, LiPF ₆ , an organic solvent such as tetrahydrofuran,
Since a non-aqueous electrolyte using LiCF ₃ SO ₃ , LiClO ₄ , LiBF ₄ or the like as an electrolyte is used, current flows between the positive electrode and the negative electrode due to misuse of the battery, and heat is generated due to the resistance of the electrolyte. The temperature inside the battery rises significantly,
Finally, there is a risk of causing a serious accident such as a fire or rupture. Therefore, to prevent such accidents, lithium 2
The secondary battery is provided with various mechanisms for safety measures. For example, a current interrupting device is configured to forcibly cut off a part of an external circuit by utilizing the fact that the internal pressure of a battery rises due to evaporation of an electrolytic solution when the temperature of the battery rises. is there. Further, a shutdown mechanism of the battery separator is one of the safety mechanisms, and various proposals have been made. For example, a porous film made of a mixture of polyethylene having a melting point at a shutdown start design temperature and polypropylene having a melting point of about 30 ° C. higher than polyethylene (JP-A-4-206257)
And a laminated porous membrane obtained by laminating porous films of thermoplastic polymers having different melting points (specifically, a porous film of polyethylene and a porous film of polypropylene) (Japanese Patent Laid-Open No.
181651, JP-A-62-10857) and the like. In each of these methods, the electric current (hereinafter, simply referred to as resistance) of the porous film is blocked by the melted resin and the electric current (hereinafter, simply referred to as resistance) increases, thereby interrupting the electric current. By doing so, the shutdown starts at a low temperature, and the high melting point polypropylene does not melt when the polyethylene is melted, and works to maintain the membrane shape of the separator, so that a sufficient heat-resistant temperature can be obtained.

[0006]

By the way, lithium 2
A non-aqueous secondary battery such as a secondary battery, a wound material obtained by inserting a positive electrode material and a negative electrode material with a battery separator interposed therebetween, is inserted into a battery can, and impregnated with a non-aqueous electrolyte solution. It is manufactured by sealing a battery can. However, in such a non-aqueous secondary battery, the resistance value of the battery separator fluctuates in the battery, and current flows intensively in a portion where the resistance value is abnormally small. The reaction in the positive electrode material and the negative electrode material became more intense than that in other places, causing a problem that abnormal heat generation occurred. In particular, in a lithium secondary battery, the above-described abnormal heat generation may cause the precipitation of lithium tendendite, or in the worst case, may ignite or render the battery unusable. Variations in the resistance value of the battery separator are caused by interposing the separator together with the positive electrode material and the negative electrode material in a battery manufacturing process and winding the wound product in a battery can. This is because conductive fine particles adhere and the conductive fine particles penetrate the separator. Hereinafter, this point will be described in detail.

As the battery separator, a porous film of a polyolefin such as polyethylene or polypropylene as described above is mainly used, and such a porous film of a polyolefin is usually obtained by uniaxially stretching or biaxially stretching a polyolefin film. And produced by winding it around a core material. Therefore, since the separator made of such a polyolefin porous film is insulative, it is charged by generating static electricity due to friction with a stretching roll in the stretching step and friction and peeling between the separators during winding. In the battery manufacturing process,
Such a separator is set at a predetermined position in the production line in the form of a roll (roll) and is fed out by a feed reel, and each of the positive electrode material and the negative electrode material set at another position in the production line (roll). ), While being sandwiched (interposed) between the positive electrode material and the negative electrode material, and wound up together with the positive electrode material and the negative electrode material (hereinafter, this is referred to as a rewinding operation) to obtain a wound material. It is said. For this reason, at the time of unwinding from the wound material (roll) in the rewinding operation, the separators cause friction and peeling, and thereby are further charged. On the other hand, at the time of the rewinding operation, the positive electrode material (or the negative electrode material) is attached to the surface of the positive electrode material (or the negative electrode material) due to the contact with the feed reel that feeds out or the bending of the material itself. Some of the material particles fall into the air. Therefore, during the rewinding operation, active material particles dropped from the positive electrode material and the negative electrode material and fine particles floating in the air are attracted to and adhere to the charged battery separator, and together with the separator, between the positive electrode material and the negative electrode material. The fine particles having a particle size larger than the thickness of the separator and the fine particles having an acute edge penetrate the separator. As a result, the active material particles are conductive, and the suspended fine particles in the air contain a large amount of conductive fine particles. Would.

The present invention has been made in view of the above circumstances, and a battery separator which does not locally show an abnormally small resistance value between a positive electrode material and a negative electrode material in a battery, and a battery separator therefor. An object is to provide a non-aqueous secondary battery used.

[0009]

Means for Solving the Problems In order to achieve the above object, the battery separator of the present invention is designed such that the charged voltage measured at an unspecified location is always within ± 1 kV. When a battery is manufactured using such a battery separator of the present invention, the number of conductive fine particles adhering to the separator in the manufacturing process is greatly reduced, and the conductive fine particles penetrating the separator are substantially eliminated. It is possible to prevent the separator from locally exhibiting an abnormally small resistance value between the positive electrode material and the negative electrode material in the battery. That is, if the charged voltage measured at an unspecified portion of the battery separator before being used in the battery manufacturing process is always within ± 1 kV, even if the separator is charged in the battery manufacturing process, the charged The potential (charge amount) does not become too large, and a high charge amount such that fine particles whose size is larger than the thickness of the separator adheres or many fine particles (including fine particles having sharp edges) adhere locally. It is considered that this is because the separator can be prevented from being charged up to. In the above description, “the charged voltage measured at the unspecified portion is always within ± 1 kV” means that the charged voltage at each portion is within ± 1 kV when many portions of the separator are measured at substantially the same time. Say.

In the battery separator of the present invention,
Means that the surface resistance is A × 10⁹~ B × 10 ¹⁶Ω (A and B are 1
(Real number of 10 or more and less than 10).
With such a configuration, the conductivity between the positive electrode material and the negative electrode material in the battery
Prevents penetration of separators by conductive particles at a higher level
Is stopped. This is such a surface resistance separator
Is difficult to accumulate static electricity on the separator surface,
Before the separator is subjected to the battery manufacturing process or
During the manufacturing process, if the size of the separator is temporarily
Fine particles larger than the thickness of
Particles (including particles with sharp edges)
Even if the charge is high enough to
Immediately before the cathode is wound with the cathode and anode materials,
The electric charge (static electricity) is quickly attenuated,
It is thought to be because the charge amount is reduced to the point where no adhesion occurs.
Can be The separator has a surface resistance of 1 × 10⁹Ω not yet
In the case of full, the separator's original machine that insulates the electrodes
1 × 10¹⁷Once above
When charged to a high charge, this does not decay quickly,
Particles tend to adhere.

In the battery separator according to the present invention, it is preferable that the time required for the charged voltage to attenuate to 2.5 kV after the charging process is performed to be 5 kV is 1 minute or more and 15 hours or less. . Such preferred separator's charging voltage attenuation characteristics (the time from charging and charging to 5 kV until charging voltage attenuates to 2.5 kV is from 1 minute to 15 hours) is substantially the same as that of the separator. And a surface resistance of 1 × 1
The decay time of the charged voltage of the ⁰⁹ Ω separator is approximately 1 minute, and the decay time of the charged voltage of the separator having a surface resistance of 1 × 10 ¹⁷ or more exceeds 15 hours.

In the non-aqueous secondary battery of the present invention, a wound material obtained by winding a positive electrode material and a negative electrode material with the battery separator of the present invention interposed therebetween is accommodated in a battery can. It becomes. In such a non-aqueous secondary battery of the present invention, the separator interposed between the positive electrode material and the negative electrode material maintains a uniform resistance value without penetration by the conductive fine particles. Highly reliable non-aqueous system 2 with no current concentration and no abnormal heat generation or ignition
Next battery.

[0013]

DETAILED DESCRIPTION OF THE INVENTION The separator of the present invention, namely,
There is no particular limitation on the method for obtaining a separator whose charged voltage measured at an unspecified portion is always within ± 1 kV, and various methods can be used according to the material and form of the separator and its manufacturing process.

For example, when manufacturing a separator comprising a porous polyolefin membrane, as described above, the polyolefin is formed into a film, and this film is made porous by uniaxial stretching or biaxial stretching.
Controlling the rotation speed of the stretching roll in the stretching process of the polyolefin film, the rotating speed of the take-up reel in the winding process of the stretched film (porous film), and the temperature and humidity of the environment in which the stretching process and the winding process are performed. By doing so, the charging characteristics of the obtained polyolefin porous membrane (separator) can be adjusted to the charging characteristics in which the charged voltage measured at the unspecified location is always within ± 1 kV. Further, the charging characteristics of the polyolefin porous film (separator) obtained by kneading an antistatic agent into the raw material of the polyolefin or applying or spraying the antistatic agent on the stretched film (porous film) are as described above. The charging characteristics can be adjusted so that the charged voltage measured at the unspecified location is always within ± 1 kV. In addition, usually, the manufactured separator is packaged as a roll and transported to a battery manufacturing site.At this transport, the amount of charge may increase due to friction between the separator and the packaging material.
Preferably, the packaging material is subjected to an antistatic treatment.

The antistatic agent mixed into the raw material of the polyolefin and the antistatic agent applied or sprayed on the stretched film (porous film) are not particularly limited. For example, anionic, nonionic or cationic charging agents may be used. An antistatic agent or an organic or inorganic salt type antistatic agent is used. When the antistatic agent is mixed with the raw material of the polyolefin, generally 0.01 to 5% by weight based on the whole raw material constituting the surface layer of the separator (porous membrane),
Preferably, 0.5 to 3% by weight is added. When the antistatic agent is applied or sprayed, usually, a solution obtained by dissolving the antistatic agent in an appropriate solvent is applied or sprayed on the surface of the separator (porous membrane), and then dried.

The present invention is applied to a single-layer or laminated polyolefin porous membrane separator. Specifically, a mixture of polyethylene and polypropylene (alloy)
And a separator formed by laminating a porous film of a mixture of polyethylene and polypropylene (alloy) and a porous film of polypropylene. As a laminate in which a porous film of a mixture of polyethylene and polypropylene (alloy) and a porous film of polypropylene are laminated, a laminate in which a porous film of polypropylene is laminated on a porous film of a mixture of polyethylene and polypropylene (alloy), A laminate in which a porous film of polyethylene and polypropylene is laminated on both sides of a porous film of a mixture of polyethylene and alloy (alloy), and a laminate in which porous films of a mixture of polyethylene and polypropylene (alloy) are laminated on both sides of a porous film of polypropylene And a laminate in which a porous film of a mixture (alloy) of polyethylene and polypropylene and a porous film of polypropylene are alternately laminated so that the total number of layers is 4 or more.

[0017]

The present invention will be described below in detail with reference to examples. (Example 1) PP (polypropylene) having a weight average molecular weight of 980,000 was used for a surface layer, and the same mixture of 50% by weight of PP and 50% by weight of high density PE (polyethylene) having a weight average molecular weight of 260,000 was used for an intermediate layer. Extrusion temperature 250 ° C., draw ratio 30 and total thickness 32 μm (thickness of each layer PP layer / intermediate layer / PP layer = 10 /
(11/11 μm). This film is placed in a clean room at a temperature of 25 ° C and a relative humidity of 30%.
50 μm thick PET (polyethylene terephthalate)
The film was sandwiched between two films, and the film was brought into contact with a roll surface having a surface temperature of 150 ° C. for approximately 10 seconds, heat-treated and wound on an iron core. This was further placed in a dryer at 125 ° C. and heat-treated for 48 hours. Subsequently, this heat-treated film is
The film is stretched at 78 ° C. based on the length of the unstretched film at 78 ° C., and further 178% at 120 ° C. based on the length of the unstretched film.
The film was stretched (total stretching ratio 256%; 3.56 times the length of the unstretched film), and further contracted at 120 ° C. by 26% based on the length of the stretched film (final stretching ratio 163). %; 2.63 times the length of the unstretched film). Table 1 shows the properties of the porous film A-1 thus obtained.

[0018]

[Table 1]

Next, this porous film A-1 was replaced with (R-CONH).
_{-CH 2 -CH 2 -N (CH 3} ) 2 -CH 2 -CH 2 -
OH) ⁺ (NO ₃ ) ^{− where} R is a hydrocarbon group having 1 to 5 carbons (elements) and 3 to 11 hydrogens (elements). Treated with a wt% (wt%) aqueous solution. For treatment, a treatment liquid is put into a water tank, and the porous membrane A-
1 was passed through a water tank at a speed of 2 m / min for 1 m, then passed through a dryer at 105 ° C. at the same speed for 2 m, dried and wound up. Thus, the obtained porous film was set to A-2. When the charged voltage of the porous film A-2 was measured at 100 points every 1 m, the average value was 0.26 kV, and the maximum value was 0.8.
6 kV, minimum value = -0.68 kV, standard deviation = 0.21
kV.

Further, the porous film was charged by corona discharge treatment so that the charged voltage became 5 kV, and the time required for the charged voltage of the porous film to attenuate to 2.5 kV was measured. Was.

The surface resistance was 2.4 × 10 ¹⁴ Ω.

In the above, the weight average molecular weight of polypropylene and polyethylene is determined by GPC (gel permea).
tion chromatograph) device from Waters; G
Using PC-150C (trade name), O-dichlorobenzene as a solvent, and a column manufactured by Showa Denko; Shodex KF-
Using 80M (trade name), the cumulative deposition of the eluate was measured at a temperature of 135 ° C., and the cumulative deposition of the eluate was calculated based on the weight average molecular weight of monodisperse polystyrene.

Among the physical properties of the porous membrane A-2 (Table 1), the shrinkage rate is determined by cutting the film to a width of about 10 mm and a length of about 300 mm so that the length direction matches the machine direction. At 60 ° C. with no tension placed on compressed paper
The film was put into a hot-air circulating dryer maintained for 1 hour, and the length of the film before and after heating was measured, and the length was determined from the decrease rate.

The Gurley value is a Gurley type densometer No. manufactured by Yasuda Seiki Seisakusho according to JIS K-8117.
323-Auto (trade name), film area 642 mm
^2. Measure the time for 10 cc of air to permeate through
It was obtained by multiplying by 0.

The porosity was obtained by calculating the specific gravity of the separator and the specific gravity of air by measuring the mass V obtained by cutting a separator having a certain area and multiplying the separator by the average thickness.

The thickness is 1/100 of the total thickness of the porous membrane.
The thickness of each layer was determined by freeze breaking the film and observing the cross section with an optical microscope.

Example 2 The porous film A-1 obtained in Example 1 was used as an antistatic agent (Analytical Chemical Laboratories, USA).
It was treated in the same manner as in Example 1 with a 1 wt% aqueous solution of ratories (Staticide (trade name)) to obtain a porous membrane A-3. When the charged voltage of the porous film A-3 was measured at 100 points every 1 m, the average value was 0.17 kV, and the maximum value was 0.54.
kV, minimum value = −0.32 kV, standard deviation = 0.17 k
V.

Further, the porous film was charged by corona discharge treatment so that the charged voltage became 5 kV, and the time required for the charged voltage of the porous membrane to attenuate to 2.5 kV was measured. there were.

The surface resistance was 4.5 × 10 ¹⁰ Ω.

(Example 3) The manufacturing process of the porous membrane A-1 obtained in Example 1 is substantially the same as that of Example 1, except that a static elimination blower is installed in each part where a stretching process, a rewinding process, and a cutting process are performed. Then, the charge of the porous film charged in each step was eliminated, and the reeling-out of the porous film or the winding speed of the porous film in each step was always 30 m / min or less. The porous membrane produced in this manner was designated as A
-4. The charged voltage of the porous membrane A-4 is set to 100 every 1 m.
As a result of measuring the points, the average value was 0.67 kV, the maximum value was
1.52 kV, minimum value = −0.49 kV, standard deviation =
It was 0.44 kV.

Further, the separator was charged by corona discharge treatment so that the charged voltage became 5 kV, and the time required for the charged voltage of the separator to attenuate to 2.5 kV was measured to be 17 minutes.

The surface resistance was 6.2 × 10 ¹⁶ Ω.

Comparative Example 1 The porous membrane A-1 obtained in Example 1 was used as it was. When the charged voltage of the porous film A-1 was measured at 100 points every 1 m, the average value was 6.2 k.
V, the maximum value was 9.4 kV, the minimum value was -2.4 kV, and the standard deviation was 3.1 kV.

Further, the separator was charged by corona discharge treatment so that the charged voltage became 5 kV, and the time required for the charged voltage of the separator to attenuate to 2.5 kV was measured to be 17 minutes.

The surface resistance was 6.1 × 10 ¹⁶ Ω.

(Comparative Example 2) Reel speed at the time of rewinding is set to 7
A porous film A-5 was produced in exactly the same manner as in Example 3 except that the speed was set to 0 m / min. When the charged voltage of this porous film A-5 was measured at 100 points every 1 m, the average value was
3.4 kV, maximum value = 4.6 kV, minimum value = -1.2 k
V, standard deviation = 1.75 kV.

Further, the separator was charged by corona discharge treatment so that the charged voltage became 5 kV, and the time required for the charged voltage of the separator to attenuate to 2.5 kV was measured to be 17 minutes.

The surface resistance was 6.2 × 10 ¹⁶ Ω.

Comparative Example 3 A porous film A-6 was produced in exactly the same manner as in Example 3 except that the environment of the clean room was 25 ° C. and the relative humidity was 1%. When the charged voltage of the porous film A-6 was measured at 100 points every 1 m, the average value was 6.7 kV, the maximum value was 11.4 kV, the minimum value was -8.6 kV, and the standard deviation was 4.2 kV. Was.

Further, the separator was charged by corona discharge treatment so that the charged voltage became 5 kV, and the time required for the charged voltage of the separator to attenuate to 2.5 kV was measured to be 17 minutes.

The surface resistance was 6.4 × 10 ¹⁶ Ω.

(Comparative Example 4) The porous membrane A-4 obtained in Example 3 was rolled into a roll (rolled) having a width of 6 cm and a length of 800 m and packaged in a polyethylene bag not subjected to an antistatic treatment. These were packed in a cardboard box in sets of 10 and transported 200 km back and forth by truck.
−7.

The charged voltage of the porous membrane A-7 is set to 100 per 1 m.
The average value was 1.8 kV and the maximum value was
3.1 kV, minimum = -1.9 kV, standard deviation = 1.1
kV.

Further, the porous film was charged by corona discharge treatment so that the charged voltage became 5 kV, and the time required for the charged voltage of the porous film to attenuate to 2.5 kV was measured to be 17 minutes. Was.

The surface resistance was 6.2 × 10 ¹⁶ Ω.

The porous films (A-1 to A-7) of Examples 1 to 3 and Comparative Examples 1 to 4 were used as separators, and LiCoO ₂ as an active material was formed on an aluminum foil as a positive electrode material.
And a mixture obtained by applying and drying a mixture of carbon and N-methylpyrrolidone (NMP) as a conductive additive (rolled material), and a mixture of graphite and NMP as an active material on an electrolytic copper foil as a negative electrode material (Volume) obtained by applying and drying, a mixture of ethylene carbonate and ethyl methyl carbonate in a volume ratio of 1: 2 as an electrolytic solution to have a concentration of lithium hexafluorophosphate of 1.2 mol / dm ^3. The thus-dissolved materials were set on a battery production line, and 1,000 Li-ion secondary batteries were manufactured for each porous membrane. Then, the resistance of the battery was measured, and a battery having a resistance value of 2 kΩ or less was determined to be an internal short circuit failure (penetration of the separator by conductive fine particles occurred). The resistance value of the battery is measured using a resistance meter such as a tester.
The measurement was performed with the measurement terminals applied to the positive electrode and the negative electrode.

Table 2 below shows the occurrence rate of the internal short-circuit failure and the standard deviation of the resistance value of the battery.

[0048]

[Table 2]

As shown in Table 2, internal short-circuit failure of the battery when the porous films of Examples 1 to 3 (the porous films whose charged voltages measured at arbitrary plural points were always within ± 1 kV) were used. Was significantly lower than that in the case of using the porous membranes of Comparative Examples 1 to 4 (porous membranes showing a charged voltage of more than 1 kV). Also, the variation in the resistance value of the battery was clearly smaller than that of Comparative Examples 1 to 4.

[0050]

As described above, according to the battery separator of the present invention, since the charged voltage measured at an unspecified portion is always within ± 1 kV, the separator can be used as a positive electrode material and a negative electrode in the battery manufacturing process. When interposed between these together with the material and tightened, conductive fine particles are suppressed from adhering to the separator and penetrating through the separator,
As a result, it is possible to prevent the separator from locally exhibiting an abnormally small resistance value between the positive electrode material and the negative electrode material in the battery.

According to the non-aqueous secondary battery of the present invention,
A separator interposed between the positive electrode material and the negative electrode material by storing the wound material obtained by winding the positive electrode material and the negative electrode material between them with the battery separator of the present invention interposed therebetween in a battery can. Can maintain a uniform resistance value without locally exhibiting an abnormally small resistance value. As a result, it is possible to obtain a highly reliable non-aqueous secondary battery that does not cause abnormal heat generation or ignition. .

Claims (4)

[Claims] 1. The charging voltage measured at an unspecified location is always ± 1.
Battery separator within kV. 2. The surface resistance is A × 10 ^{9 to} B × 10 ¹⁶ Ω.
The battery separator according to claim 1, wherein (A and B are real numbers of 1 or more and less than 10). 3. The battery separator according to claim 1, wherein the time required for the charged voltage to attenuate to 2.5 kV after charging and charging to 5 kV is 1 minute or more and 15 hours or less. 4. The method according to claim 1, wherein a positive electrode material and a negative electrode material are interposed therebetween.
A non-aqueous secondary battery in which a wound product wound with the battery separator according to any one of the above items 3 to 3 is accommodated in a battery can.