KR101042054B1 - Nonaqueous electrolyte secondary battery and method for fabricating the same - Google Patents

Abstract

The positive electrode 4 having the positive electrode active material formed on the positive electrode current collector 4A, and the negative electrode 5 having the negative electrode active material formed on the negative electrode current collector 5A are wound or laminated through the porous insulating layer 6. The electrode group is constituted, the tensile elongation of the positive electrode 4 is 3.0% or more, and the porous insulating layer 6 is made of a material containing aramid resin. As a result, even if the nonaqueous electrolyte secondary battery is crushed due to crushing, the occurrence of internal short circuit in the battery can be prevented, and abnormal heat generation caused by internal short circuit can be suppressed.

Tensile Elongation, Porous Insulation Layer, Aramid Resin, Crush, Internal Short Circuit

Description

Non-aqueous electrolyte secondary battery and manufacturing method thereof {NONAQUEOUS ELECTROLYTE SECONDARY BATTERY AND METHOD FOR FABRICATING THE SAME}

TECHNICAL FIELD The present invention relates to a nonaqueous electrolyte secondary battery and a method for manufacturing the same, and more particularly, to a nonaqueous electrolyte secondary battery capable of suppressing occurrence of internal short circuit due to crushing and a method for manufacturing the same.

In recent years, small size and light weight secondary batteries capable of rapid charging and large current discharge have been demanded in response to demands for vehicle mounting or demand for large tool DC. As a typical battery that satisfies these requirements, a material such as carbon that can occlude and release lithium ions is used as a negative electrode active material, and a material such as lithium cobalt composite oxide that reversibly electrochemically reacts with lithium ions is used as a positive electrode active material, LiClO ₄ or LiPF ₆ can be given such a non-aqueous electrolyte secondary battery of the dissolved non-proton (proton) castle organic solvent as an electrolyte lithium salt.

In this nonaqueous electrolyte secondary battery (hereinafter, simply referred to as a "battery"), a positive electrode in which a positive electrode active material is formed on a positive electrode current collector, and a negative electrode in which a negative electrode active material is formed on a negative electrode current collector are wound through a separator (porous insulating layer). Or the stacked electrode group together with the electrolyte solution, and the opening of the battery case is sealed with a sealing plate.

However, when an internal short circuit occurs in the nonaqueous electrolyte secondary battery, current flows into the battery due to the internal short circuit, resulting in an increase in the temperature in the battery. There are many factors that cause internal short-circuits, but especially when the battery is clumped due to crushing, a large current flows instantaneously, and thus there is a concern that the temperature in the battery may increase rapidly.

In general, a porous insulating layer (for example, a polyolefin layer) used as a separator has a so-called blocking function, in which a temperature inside a battery rises due to internal short-circuit and becomes high when the temperature becomes high, thereby preventing current from flowing. However, when the heat generation is severe, the porous insulating layer is melted and shrunk and the short circuit portion is enlarged, which makes it difficult to suppress abnormal heat generation.

Therefore, as a method of suppressing such abnormal heat generation, Patent Document 1 (Japanese Patent Laid-Open No. 2000-100408) discloses a porous insulating layer having a conventional blocking function for a separator and a heat resistant porous insulating layer (for example, , A polyimide layer, an aramid layer, etc.) is described. The separator having such a laminated structure can suppress abnormal heat generation by preventing expansion of the short circuit portion by the heat resistant porous insulating layer when the heat generation becomes severe and the blocking function is lost while maintaining the original blocking function.

Patent Document 2 (Japanese Patent Laid-Open No. 2001-297763) discloses a method of suppressing the magnitude of short-circuit current flowing during an internal short circuit by increasing the specific resistance of the positive electrode active material, thereby suppressing abnormal heat generation. have.

[Initiation of invention]

[Problem to Solve Invention]

In the conventional method of suppressing abnormal heat generation due to internal short circuit, when internal short circuit occurs, it is possible to suppress the magnitude of the short circuit current flowing at the time of short circuit, and it is not an essential solution to prevent the internal short circuit. Therefore, there is a concern that abnormal heat generation cannot be sufficiently suppressed depending on the degree of internal short circuit. In addition, if the effect of suppressing the magnitude of the short-circuit current is to be increased, the result is that the original performance of the battery is reduced (for example, when the specific resistance of the positive electrode active material is increased, the high rate discharge characteristic is lowered). There is a certain limit to the effect of suppressing.

SUMMARY OF THE INVENTION The present invention has been made in view of this point, and even if the nonaqueous electrolyte secondary battery is crushed due to crushing, it prevents the internal short circuit occurring in the battery and prevents abnormal heat generation due to the internal short circuit. It is an object to provide a secondary battery.

[Means for solving the problem]

A nonaqueous electrolyte secondary battery according to the present invention is a nonaqueous electrolyte including an electrode group in which a positive electrode having a positive electrode active material formed on a positive electrode current collector, and a negative electrode having a negative electrode active material formed on a negative electrode current collector wound or stacked through a porous insulating layer. It is an electrolyte secondary battery, The tensile elongation of a positive electrode is 3.0% or more, The porous insulating layer is characterized by consisting of a material containing an aramid resin.

With such a configuration, even if the nonaqueous electrolyte secondary battery is crushed due to crushing, the tensile elongation of the positive electrode is large, so that the positive electrode is not broken, thereby preventing the occurrence of internal short circuit in the battery. In addition, even if the anode breaks as a result of insufficient tensile elongation of the anode due to variations in the manufacturing process, the porous insulating layer is made of a material containing aramid resin having a large frictional force against the anode, thereby following the porous insulating layer to the broken anode. By moving, the position of the fracture surface of the anode can thus be maintained at the end of the porous insulating layer. As a result, it is possible to prevent the broken anode from contacting the cathode, thereby preventing the occurrence of an internal short circuit.

[Effects of the Invention]

According to the present invention, even if the nonaqueous electrolyte secondary battery is agglomerated due to crushing, the positive electrode is not broken, the internal short circuit can be prevented from occurring, and the positive electrode has insufficient tensile elongation due to variations in the manufacturing process. Even if this breaks, the broken positive electrode can be prevented from occurring inside the battery without touching the negative electrode. Accordingly, it is possible to provide a nonaqueous electrolyte secondary battery having excellent safety without abnormal heat generation due to an internal short circuit.

1 is a cross-sectional view showing the configuration of a nonaqueous electrolyte secondary battery in the embodiment of the present invention.

2 is an enlarged cross-sectional view showing the configuration of the electrode group in the embodiment of the present invention.

Figure 3 (a) is a view showing the fracture state of the positive electrode due to the collapse when using a separator containing no aramid resin, (b) is a fracture state of the positive electrode due to the collapse when using a separator containing aramid resin It is a figure which shows.

[Description of the code]

1: battery case 2: sealing plate

3: gasket 4: anode

4A: positive electrode current collector 4B: positive electrode mixture layer

4a: anode lead 5: cathode

5A: negative electrode current collector 5B: negative electrode mixture layer

5a: negative electrode lead 6: separator

8: electrode group

BEST MODE FOR CARRYING OUT THE INVENTION [

When the non-aqueous electrolyte secondary battery is agglomerated due to crushing, the applicant of the present application examines a factor in which internal short circuit occurs in the battery, and thus, the positive electrode, the negative electrode, and the positive electrode having the smallest tensile elongation among the electrode groups are preferred. As a result, it was found that the breakage portion of the positive electrode penetrated the separator and the positive electrode plate and the negative electrode plate were short-circuited.

Therefore, as a result of further examining the method of increasing the tensile elongation rate of the positive electrode, the effect of increasing the tensile elongation rate of the positive electrode was found by performing heat treatment at a predetermined temperature after rolling the positive electrode current collector coated with the positive electrode mixture layer. Usually, after apply | coating a positive electrode mixture layer to a positive electrode electrical power collector, heat processing is performed for the purpose of improving the adhesiveness of a positive electrode mixture layer and a positive electrode electrical power collector (for example, patent document 3 (Unexamined-Japanese-Patent No. 5-182692). ), 4 (see Japanese Patent Application Laid-Open No. 7-105970), etc.), although the tensile elongation of the positive electrode is temporarily increased by this heat treatment, the tensile elongation is lowered again after the rolling treatment. It is not possible to increase the tensile elongation of.

Based on these findings, the present applicant has disclosed a method of suppressing the occurrence of internal short circuit in a crushed nonaqueous electrolyte secondary battery by setting the tensile elongation rate of the positive electrode to a predetermined value or more, Japanese Patent Application No. 2007-323217 (PCT / JP2008 / 002114).

That is, after coating and drying the positive electrode mixture slurry containing a positive electrode active material on a positive electrode current collector, the positive electrode current collector with which the positive electrode mixture slurry was apply | coated and dried, after a while, heat-processing the rolled positive electrode current collector to predetermined temperature, The positive electrode tensile elongation rate after rolling can be 3.0% or more. As a result, even if the nonaqueous electrolyte secondary battery is crushed due to the crushing, the positive electrode does not break preferentially, so that occurrence of internal short circuit in the battery can be prevented.

As described above, it is considered that the tensile elongation of the positive electrode can be increased to 3.0% or more by the heat treatment after rolling as follows.

That is, since the positive electrode mixture layer is formed on the surface of the positive electrode current collector, the tensile elongation of the positive electrode is not limited to the intrinsic tensile elongation of the positive electrode current collector itself. Usually, since the positive electrode mixture layer has a lower tensile elongation rate than the positive electrode current collector, when the positive electrode that is not subjected to heat treatment after rolling is elongated, a large crack occurs in the positive electrode mixture layer and the positive electrode breaks. This is thought to be because the tensile stress in the positive electrode mixture layer increases with the extension of the positive electrode, and the tensile stress applied to the positive electrode current collector is concentrated at a portion where a large crack has occurred.

On the other hand, when the positive electrode heat-treated after rolling is elongated, the positive electrode current collector is softened, and thus the positive electrode current collector is continuously elongated while generating a large number of fine cracks in the positive electrode mixture layer, and the positive electrode breaks soon. Since the tensile stress applied to the positive electrode current collector is dispersed by the occurrence of fine cracks, the impact on the current collector due to the occurrence of cracks in the positive electrode mixture layer is small, and the crack continues to a certain size without breaking the positive electrode at the same time. It is thought that the positive electrode current collector was broken when the tensile stress reached a constant size (a value close to the tensile elongation rate inherent to the current collector).

The tensile elongation of the positive electrode is obtained by the heat treatment after rolling, if the cathode size is different in, for example, formed with the entire amount of the positive electrode collector of aluminum and the positive electrode material mixture layer to the LiCoO ₂ as a cathode active material depending on the material of the positive electrode collector and positive electrode active material, By performing the heat treatment (180 seconds) after rolling at the temperature of 200 degreeC or more, the tensile elongation rate of a positive electrode can be raised to 3% or more. The heat treatment temperature is preferably higher than the softening temperature of the positive electrode current collector and lower than the decomposition temperature of the binder.

Table 1 shows, the entire amount of the positive electrode collector of aluminum, a table showing the test results of pressure collapse when making a battery using the positive electrode A positive electrode material mixture formed cheungreul that the LiCoO ₂ as a cathode active material. Herein, the batteries 1 to 4 are subjected to the heat treatment conditions after rolling of the positive electrode at a temperature of 280 ° C. by changing the heat treatment time to 10 seconds, 20 seconds, 120 seconds, and 180 seconds. The battery 5 is not subjected to the heat treatment after rolling.

Heat treatment of anode after rolling
Anode after rolling
Tensile elongation
[%] Crush test Heat treatment temperature
[%] Heat Treatment Time [sec] Paragraph depth
[mm] Battery 1
280
10 3.0 8 Battery 2 20 5.0 9 Battery 3 120 6.0 10 Battery 4 180 6.5 10 Battery 5 - - 1.5 5

As shown in Table 1, the tensile elongation of the positive electrode of the battery 5 not subjected to the post-rolling heat treatment is 1.5%, whereas the tensile elongation of the positive electrode of the batteries 1 to 4 subjected to the post-rolling heat treatment is 3 to 6.5%. It can be seen that the larger each. As a result of performing a crushing test (battery deformation amount (shorting depth) at the time when an internal short circuit occurred in the battery by pressing the battery at a rate of 0.1 mm / sec with a round bar of 6 Φ) for each battery, As shown, the short-circuit depth of the battery 5 not subjected to the post-roll heat treatment was 5 mm, whereas the short-circuit depth of the batteries 1 to 4 subjected to the post-roll heat treatment was deepened to 8 to 10 mm. . That is, by performing a predetermined heat treatment after rolling, the tensile elongation of the positive electrode can be 3% or more, thereby preventing the occurrence of internal short circuit due to crushing.

Here, when the heat treatment temperature after rolling is high or the heat treatment time is long, the binder contained in the positive electrode mixture layer is melted, and there is a fear that the battery capacity is reduced when the positive electrode active material is coated with the melted binder. In order to prevent the battery capacity drop caused by the heat treatment after rolling, the above-mentioned application specification discloses that it is preferable to use aluminum containing iron as the positive electrode current collector. By using the positive electrode current collector made of aluminum containing iron, the heat treatment temperature after rolling required for obtaining the tensile elongation rate of the predetermined positive electrode can be lowered or the heat treatment time can be shortened. Thereby, the fall of the battery capacity by the heat processing after rolling can be prevented.

The inventors of the present invention fabricated a nonaqueous electrolyte secondary battery having a positive electrode in which the tensile elongation rate of the positive electrode was increased to 3% or more by heat treatment after rolling, and examined the safety against crushing. It was found that some batteries were broken and an internal short circuit occurred.

Although the tensile elongation rate of a positive electrode can be controlled by the heat processing conditions performed after rolling, it is not only these heat processing conditions but actually, for example, the thickness of a positive electrode collector, the ratio of the binder contained in a positive electrode mixture layer, etc., Various factors which affect the tensile elongation of a positive electrode may not be able to obtain a desired tensile elongation rate (for example, about 3%) because a deviation generate | occur | produces in a manufacturing process. The battery in which the internal short circuit occurs due to the crushing is caused by the breakage of the positive electrode as a result of the variation in the manufacturing process such that the tensile elongation of the positive electrode does not become a desired value and does not have sufficient tensile elongation with respect to the crushing. I think.

Therefore, the inventors of the present application have come to assume the present invention as a result of examining a method for preventing the occurrence of an internal short circuit, even if the positive electrode is broken due to insufficient tensile elongation of the positive electrode due to variations in the manufacturing process.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described, referring drawings. In addition, this invention is not limited to the following embodiment. Moreover, about the structure of the nonaqueous electrolyte secondary battery demonstrated by this embodiment, the structure described in the said application specification by this application can be applied.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows typically the structure of a nonaqueous electrolyte secondary battery in embodiment of this invention.

As shown in FIG. 1, the electrode group 8 in which the positive electrode 4 and the negative electrode 5 are wound through a separator (porous insulating layer) is accommodated in the battery case 1 together with the electrolyte solution. The opening of the battery case 1 is sealed with the sealing plate 2 via the gasket 3. The positive lead 4a attached to the positive electrode 4 is connected to the sealing plate 2 serving as the positive electrode terminal, and the negative lead 5a attached to the negative electrode 5 is connected to the battery case 1 serving as the negative electrode terminal. do.

2 is an enlarged cross-sectional view schematically showing the configuration of the electrode group 8 in the present embodiment.

As shown in FIG. 2, the positive electrode mixture layer 4B is formed on both surfaces of the positive electrode current collector 4A, and the negative electrode mixture layer 5B is formed on both sides of the negative electrode current collector 5A. The separator 6 is disposed between the cathodes 5.

Here, the tensile elongation of the positive electrode 4 is 3.0% or more, and the separator 6 is made of a material containing aramid resin.

By setting the tensile elongation rate of the positive electrode 4 to 3.0% or more, even if the nonaqueous electrolyte secondary battery is crushed due to crushing, it is possible to prevent the internal short circuit in the battery without breaking the positive electrode 4. In addition, even if the anode 4 breaks due to insufficient tensile elongation (less than 3.0%) due to variations in the manufacturing process, the aramid resin having a large friction force with respect to the separator 6 is formed. By constructing a material including the above, the broken anode 4 can be prevented from contacting the cathode 5.

Here, the "tensile elongation" of the present invention refers to the rate at which the test piece is stretched when the test piece is pulled and the test piece is broken. For example, the electrode plate having a width of 15 mm and an effective part length of 20 mm at a speed of 20 mm / min. It pulls out and is calculated | required by the elongation rate at the time when a pole plate is broken.

Next, the mechanism which can prevent the broken anode 4 from contacting the cathode 5 by employing the separator 6 containing aramid resin while referring to FIGS. 3A and 3B will be described. .

FIG. 3 (a) is a diagram showing a state when the anode 4 is broken due to crushing when the separator 6 made of a material (for example, a polyolefin layer) containing no aramid resin is used. to be. Since the conventional separation membrane 6 has a small frictional force with respect to the positive electrode 4 and is easy to slide, the separation membrane 6 does not move following the broken positive electrode 4, and the broken positive electrode 4 is the negative electrode 5. To reach an internal short circuit.

On the other hand, FIG. 3B is a diagram showing a state when the anode 4 breaks due to crushing when the separation membrane 6 made of aramid resin material is used. Since the separation membrane 6 has a large friction force with respect to the anode 4, the separation membrane 6 moves in accordance with the broken anode 4, and thus the position of the fracture surface of the anode 4 is changed to the end of the separation membrane 6. You can keep it at As a result, since the broken anode 4 can be prevented from touching the cathode 5, it is possible to prevent the occurrence of an internal short circuit.

Conventionally, aramid resin has been used as a material of the separator 6 which is hard to be broken by external force from the viewpoint of excellent strength. The present invention focuses on the property that the separation membrane 6 made of aramid resin-containing material has a large frictional force with respect to the positive electrode 4. Therefore, the separation membrane of the present invention may include an aramid resin to the extent that it can exert a constant frictional force, but in order to exert the above-described effects more effectively, the separator includes a material containing only 20% by weight or more of aramid resin (including only aramid resin). It is preferable to use a separated membrane. In addition, from the viewpoint of maintaining the blocking function of the separator, it is preferable to use a material containing 45% by weight or less of aramid resin.

Here, as an aramid resin, For example, poly (paraphenylene terephthalamide), poly (parabenzamide), poly (4,4'- benzanilide terephthalamide), poly (paraphenylene-2, 6- naphthalene) Dicarboxylic acid amide), poly (2-chloroparaphenylene terephthalamide) polyphenylene terephthalamide / 2,6-dichloroparaphenylene terephthalamide, and the like.

Moreover, you may comprise the separator 6 by the 1st separator made of the material containing the aramid resin of this invention, and the 2nd separator which has a blocking function which becomes a nonporous layer at high temperature. With such a laminated structure, in addition to the above-described effects, even when the first separation membrane is made of a material containing 45% by weight or more of aramid resin, the second separation membrane can maintain the blocking function. In this case, the first separator is in contact with the positive electrode 4 and needs to be disposed between the positive electrode 4 and the negative electrode 5. As the second separator, a separator made of polyolefin resin such as polyethylene or polypropylene can be used, for example. In addition, the first separator may include an inorganic material. By adding an inorganic material, the heat resistance of a heat resistant layer (layer containing an aramid resin) can be improved. Specific examples of the inorganic material include alumina, magnesium, zirconium, titania, yttria, zeolite, silicon nitride, silicon carbide, and the like. These may be used independently and may be used in combination of 2 or more type.

In the present invention, the positive electrode 4 and the negative electrode 5 constituting the electrode group 8 shown in FIG. 2 are not particularly limited in their materials and manufacturing methods, but the following materials and manufacturing methods can be applied. In addition, of course, the electrode group 8 may be a laminate in which the anode 4 and the cathode 5 are not wound via the separator 6 but are laminated.

As the positive electrode current collector 4A, aluminum, stainless steel, titanium, or the like can be used, for example. In particular, when aluminum containing iron is used, the heat treatment temperature after rolling of the anode 4 can be lowered, or the heat treatment time can be shortened. The iron content in the positive electrode current collector 4A is preferably in the range of 1.20 to 1.70 wt%.

The positive electrode mixture layer 4B may include a binder, a conductive agent, and the like in addition to the positive electrode active material. As the positive electrode active material, for example, a lithium composite metal oxide can be used. Representative materials include LiCoO ₂ , LiNiO ₂ , LiMnO ₂ , LiCoNiO ₂ , and the like. As the binder, for example, polyvinylidene fluoride (PVDF), a derivative of PVDF, or a rubber-based binder (for example, fluorine rubber and acrylic rubber) is suitably used. Moreover, as a electrically conductive agent, materials, such as graphite, such as smoking, and carbon black, such as acetylene black, can be used, for example.

The positive electrode 4 is formed by coating and drying a positive electrode mixture slurry containing a positive electrode active material on the positive electrode current collector 4A, and then rolling the positive electrode current collector 4A to which the positive electrode mixture slurry is applied and dried. It is obtained by heat-processing the collector 4A to predetermined temperature. Moreover, the heat processing conditions after rolling are controlled so that the tensile elongation rate of the positive electrode 4 may be 3% or more. However, when the tensile elongation of the positive electrode 4 exceeds 10%, when the electrode group 8 is wound and formed, since the positive electrode 4 is deformed and it is difficult to wind uniformly, the tensile elongation of the positive electrode is preferably 10% or less. Do.

As the negative electrode current collector 5A, copper, stainless steel, nickel, or the like can be used, for example. The negative electrode mixture layer 5B may contain a binder, a conductive agent, etc. in addition to the negative electrode active material. As an anode active material may be, for example, take advantage of a silicon compound in the graphite, such as carbon material or, SiO _x such as carbon fibers.

The negative electrode 5 is obtained by coating and drying the negative electrode mixture slurry containing the negative electrode active material on the negative electrode current collector 5A and then rolling the negative electrode current collector 5A to which the negative electrode mixture slurry is applied and dried.

Here, in order to achieve the effect of the present invention, the tensile elongation of the cathode 5 and the separation membrane (porous insulating layer) 6 needs to be 3% or more.

As mentioned above, although this invention was demonstrated by the preferable embodiment, this description is not a restriction | limiting and various modifications are of course possible. For example, in the said embodiment, although the lithium ion secondary battery was demonstrated to the nonaqueous electrolyte secondary battery as an example, it can apply also to other nonaqueous electrolyte secondary batteries, such as a nickel hydrogen storage battery, in the range which exhibits the effect of this invention. In addition, the present invention exhibits an effect of preventing the occurrence of internal short circuit in the battery due to crushing, and prevents buckling of the electrode group or fracture of the electrode plate due to expansion and contraction of the negative electrode active material due to charge and discharge of the battery. Applicable to

INDUSTRIAL APPLICABILITY The present invention is useful for a nonaqueous electrolyte secondary battery having an electrode group suitable for high current discharge. For example, a drive battery for an electric tool or an electric vehicle requiring a high output, a large capacity backup power supply, a battery for a power storage power supply, and the like. Applicable

Claims (8)

In a nonaqueous electrolyte secondary battery comprising a positive electrode on which a positive electrode active material is formed on a positive electrode current collector, and a negative electrode on which a negative electrode active material is formed on a negative electrode current collector is wound or laminated through a porous insulating layer. Tensile elongation of the positive electrode is at least 3.0%, The porous insulating layer is a nonaqueous electrolyte secondary battery made of a material containing aramid resin. The method of claim 1, Tensile elongation of the negative electrode is at least 3.0%, The non-aqueous electrolyte secondary battery having a tensile elongation of 3.0% or more of the porous insulating layer. The method of claim 1, The positive electrode is a non-aqueous electrolyte secondary battery which is heat-treated at a predetermined temperature after rolling the positive electrode current collector, the positive electrode mixture slurry containing the positive electrode active material is coated and dried. The method of claim 1, The porous insulating layer is a nonaqueous electrolyte secondary battery comprising a first porous insulating layer made of a material containing the aramid resin and a second porous insulating layer having a blocking function of forming a layer free of pores at a high temperature. The method of claim 4, wherein And the first porous insulating layer is in contact with the positive electrode and is disposed between the positive electrode and the negative electrode. The method of claim 1, The positive electrode current collector is a nonaqueous electrolyte secondary battery made of aluminum containing iron. The method of claim 6, The positive electrode current collector is a non-aqueous electrolyte secondary battery consisting of aluminum containing iron in the range of 1.20% by weight to 1.70% by weight. In the manufacturing method of the nonaqueous electrolyte secondary battery which comprises the electrode group by which the positive electrode which the positive electrode active material was formed on the positive electrode collector, and the negative electrode which the negative electrode active material was formed on the negative electrode current collector are wound or laminated through a porous insulating layer, The anode, Applying and drying a positive electrode mixture slurry containing a positive electrode active material on a positive electrode current collector, Rolling the positive electrode current collector to which the positive electrode mixture slurry is applied and dried; and The rolled positive electrode current collector is formed by a process of heat treatment at a predetermined temperature, The tensile elongation of the positive electrode after the rolling is at least 3.0%, The porous insulating layer is a method of manufacturing a non-aqueous electrolyte secondary battery made of a material containing aramid resin.

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