KR20140072794A - Non-aqueous electrolyte rechargeable battery pack - Google Patents

Abstract

The present invention relates to a non-aqueous electrolyte secondary battery and provides a new and improved non-aqueous electrolyte secondary battery pack thanks to the improved stability of the non-aqueous electrolyte secondary battery. In order to perform the task, according to an embodiment of the present invention, the non-aqueous electrolyte secondary battery pack includes an exterior body in which the non-aqueous electrolyte secondary battery is stored; an anode current collector tap which protrudes to the outside the exterior body and is connected to the anode current collector of the non-aqueous electrolyte secondary battery; a cathode current collector tap which protrudes to the outside the exterior body and is connected to the cathode current collector of the non-aqueous electrolyte secondary battery; a metal plate for anode connection which is installed on the outside of the exterior body and is connected to the anode current collector tap; a metal plate for cathode connection which is installed on the outside of the exterior body and is connected to the cathode current collector tap; and an insulation body which is placed between the metal plate for anode connection and the metal plate for cathode connection.

Description

[0001] NON-AQUEOUS ELECTROLYTE RECHARGEABLE BATTERY PACK [0002]

The present invention relates to a nonaqueous electrolyte secondary battery pack.

Patent Documents 1 and 2 disclose a non-aqueous electrolyte secondary battery such as a lithium ion secondary battery.

The nonaqueous electrolyte secondary battery uses a nonaqueous solvent such as an organic solvent as an electrolyte and an active material liable to generate heat as compared with the current collector when the secondary battery is short-circuited. Therefore, safety measures against heat generation of the active material are strongly demanded.

Patent Documents 1 and 2 disclose safety measures against heat generation of an active material generated by short-circuiting of a nonaqueous electrolyte secondary battery.

More specifically, Patent Document 1 discloses arranging a metal plate on the outer side of a laminated body and connecting the metal plate and the positive electrode tab.

According to Patent Document 1, when a conductor such as a nail penetrates through a non-aqueous electrolyte secondary battery, a first short-circuit occurs between the metal plate and the positive electrode collector of the non-aqueous electrolyte secondary battery.

Accordingly, according to Patent Document 1, since the voltage of the non-aqueous electrolyte secondary battery is lowered until short-circuiting occurs between the positive electrode active material and the negative electrode active material, heat generation of the active materials can be suppressed.

Patent Document 2 discloses that a winding element is manufactured by winding an electrode structure sheet composed of an anode, a cathode, and a separator, and the winding element is inserted into a laminate sheath and sealed.

Patent Document 2 discloses that an electrode structure sheet constituting the outermost periphery of a wound element is composed of a positive electrode collector, a negative electrode collector, and a separator.

Here, the outermost electrode structure sheet of Patent Document 2 is not coated with active material.

As a result, according to Patent Document 2, when a conductor such as a nail penetrates the non-aqueous electrolyte secondary battery, a first short circuit is generated between the positive electrode collector and the negative electrode collector constituting the outermost electrode structure sheet.

Therefore, according to Patent Document 2, since the voltage of the non-aqueous electrolyte secondary battery is lowered until short-circuiting occurs between the positive electrode active material and the negative electrode active material, heat generation of the active materials can be suppressed.

According to the above Patent Documents 1 and 2, the safety of the non-aqueous electrolyte secondary battery can be improved.

However, in recent years, more reliable safety has been demanded for non-aqueous electrolyte secondary batteries than the safety measures described in Patent Documents 1 and 2. [

1. Patent Document 1: Japanese Patent Laid-Open Publication No. 2012-28089 2. Patent Document 2: Japanese Patent Laid-Open Publication No. 2011-187241

SUMMARY OF THE INVENTION Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide a non-aqueous electrolyte secondary battery pack having improved safety and a novel and improved battery pack.

The nonaqueous electrolyte secondary battery pack according to an embodiment of the present invention includes an outer casing having a nonaqueous electrolyte secondary battery built therein, a positive electrode current collector tab protruding outside the outer casing and connected to the positive electrode current collector of the nonaqueous electrolyte secondary battery, A negative electrode current collector tab projected to the negative electrode current collector of the nonaqueous electrolyte secondary battery and connected to the negative electrode current collector of the nonaqueous electrolyte secondary battery, a metal plate for connection to the positive electrode current collector, And an insulator disposed between the metal plate for cathode connection and the metal plate for cathode connection and the metal plate for cathode connection.

Further, the insulator may have heat shrinkability.

Further, the insulator may have an area shrinkage ratio at 120 degrees of 16% or more.

The metal plate for positive electrode connection and the metal plate for negative electrode connection may be composed of one of copper, aluminum, and alloys thereof.

The metal plate for anode connection and the metal plate for cathode connection may have a thickness of 0.05 mm to 1.0 mm.

The metal plate for positive electrode connection or the metal plate for negative electrode connection includes a plurality of metal plates for positive electrode connection or a plurality of metal plates for negative electrode connection and the metal plate for positive electrode connection and the metal plate for negative electrode connection may be alternately stacked on the outside of the outer body .

The outer body includes an inner sheath housing the non-aqueous electrolyte secondary battery and an outer sheath covering the inner sheath. The metal plate for the anode connection, the metal plate for the cathode connection, and the insulator are provided outside the inner sheath, The outer sheath can be provided outside the metal plate for anode connection, the metal plate for cathode connection, and the insulator.

Further, the outer body may be a laminate type outer body.

According to an embodiment of the present invention, when the conductor passes through the non-aqueous electrolyte secondary battery pack, a first short circuit occurs outside the external body.

Therefore, it takes a certain time until a short circuit occurs between the active materials after the drop of the battery voltage starts, so that the safety of the non-aqueous electrolyte secondary battery can be improved.

1 is an exploded perspective view showing a configuration of a nonaqueous electrolyte secondary battery pack according to an embodiment of the present invention.
2 is a perspective view showing a configuration of the non-aqueous electrolyte secondary battery pack of FIG.
3 is a side sectional view showing a modification of the embodiment of Fig.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

In the description and the drawings, the same reference numerals are given to constituent elements having substantially the same functions and configurations, and redundant description will be omitted.

FIG. 1 is an exploded perspective view showing a configuration of a non-aqueous electrolyte secondary battery pack according to the present embodiment, and FIG. 2 is a perspective view showing the configuration of the non-aqueous electrolyte secondary battery pack of FIG.

Hereinafter, the nonaqueous electrolyte secondary battery pack 10 according to the present embodiment will be described with reference to Figs. 1 and 2. Fig.

The nonaqueous electrolyte secondary battery pack 10 according to the present embodiment includes a discharging unit 10a, a laminate sheath 100, a positive electrode current collector tab 110 and a negative electrode current collector tab 120. [

The discharge unit 10a is installed outside the laminate sheath 100 in such a constitution as to discharge the non-aqueous electrolyte secondary battery before short-circuiting between the active materials in the non-aqueous electrolyte secondary battery.

Here, the method of installing the discharge unit 10a in the laminate sheath 100 is not particularly limited.

For example, the discharge unit 10a can be installed in the laminated body 100 by various adhesive materials, double-sided tape, or the like.

Also, the discharge unit 10a may be installed so as to enclose the laminated outer body 100.

The discharge unit 10a is constituted by a metal plate 20 for anode connection, a metal plate 30 for cathode connection and an insulator 40. [

The metal plate 20 for positive electrode connection is provided on the outside of the laminate sheath 100 as a metal plate for short-circuiting when the conductor passes through.

More specifically, the metal plate 20 for positive electrode connection is provided on the flat surface portion of the laminate external body 100.

The metal plate for positive electrode connection (20) has a positive electrode connection protrusion (21).

The positive electrode connection protrusion 21 is connected to the positive electrode collector tab 110.

Here, the positive electrode connection protruding portion 21 and the positive electrode current collector tab 110 can be connected to each other by various methods in which electricity is communicated with each other.

For example, the positive electrode connection protruding portion 21 and the positive electrode current collector tab 110 may be connected by ultrasonic welding or the like.

The metal plate 20 for positive electrode connection may be composed of one or more kinds of metals selected from the group consisting of copper, aluminum, and alloys thereof.

Here, when the metal plate 20 for anode connection is composed of at least one of the above metals, the battery voltage at the time of short-circuiting can be remarkably and quickly lowered.

The thickness of the metal plate for positive electrode connection 20 is not particularly limited. Therefore, the thickness of the metal plate 20 for positive electrode connection can be adjusted according to the thickness of the nonaqueous electrolyte secondary battery.

However, it is preferable that the thickness of the metal plate 20 for positive electrode connection is as thick as not to impair the lightness characteristic of the laminate type secondary battery.

More specifically, the thickness of the metal plate 20 for positive electrode connection is preferably 0.05 mm to 1.0 mm.

The metal plate 30 for cathode connection is provided on the outside of the laminate sheath 100 as a metal plate for causing a short circuit when the conductor is passed.

More specifically, the metal plate 20 for positive electrode connection is provided on the flat surface portion of the laminate external body 100.

The metal plate 30 for cathode connection has a cathode connection protrusion 31.

The cathode connection protrusion 31 is connected to the anode current collector tab 120.

Here, the cathode connection protruding portion 31 and the anode current collector tab 120 can be connected to each other by various methods in which electricity is conducted to each other.

For example, the cathode connection protrusion 31 and the anode current collector tab 120 may be connected by ultrasonic welding or the like.

The metal plate 30 for cathode connection may be composed of one or more kinds of materials selected from copper, aluminum, and alloys thereof.

Here, when the metal plate 30 for cathode connection is constituted by one or more of the above metals, the battery voltage at the time of short-circuiting can be remarkably and quickly lowered.

The thickness of the metal plate 30 for cathode connection is not particularly limited. Therefore, it can be appropriately adjusted according to the thickness of the nonaqueous electrolyte secondary battery.

However, it is preferable that the thickness of the metal plate 30 for cathode connection is as thick as not to impair the light weight which is characteristic of the laminate type secondary battery.

More specifically, the thickness of the metal plate 30 for cathode connection is preferably 0.05 mm to 1.0 mm.

The insulator 40 is disposed between the positive electrode connection metal plate 20 and the negative electrode connection metal plate 30 and insulates the positive electrode connection metal plate 20 and the negative electrode connection metal plate 30 from each other.

The insulator 40 may have heat shrinkability.

When the insulator 40 has heat shrinkability, the insulator 40 may have the following functions when a short circuit between the positive electrode connection metal plate 20 and the negative electrode connection metal plate 30 is performed.

That is, when the metal plate for positive electrode connection 20 and the metal plate for negative electrode connection 30 are short-circuited, the conductor that shorts the positive electrode connection metal plate 20 and the negative electrode connection metal plate 30 generates heat, And contracts in a direction away from the conductor in a concentric circle centering on the conductor.

Therefore, since the opening centering on the conductor is formed by the insulator 40, the metal plate for anode connection 20 and the metal plate for cathode connection 30 are in contact through the opening.

Therefore, the current flowing through the positive electrode connection metal plate 20 and the negative electrode connection metal plate 30 is increased, so that the battery voltage drops more rapidly.

More specifically, the area shrinkage ratio of the insulator 40 is preferably 16% or more at 120 ° C.

Here, the area shrinkage ratio is expressed by the following equation (1).

Here, a represents the area shrinkage rate, b represents the area of the insulator 40 before the shrinkage (the area of the vertical surface in the thickness direction of the insulator 40), and c represents the area of the insulator 40 after shrinkage.

When the area shrinkage ratio is within the above range, the battery voltage at the time of short-circuiting drops more quickly.

The insulator 40 is made of one or more kinds of polymers selected from the group consisting of polyethylene, polypropylene, polyvinyl chloride, and mixtures thereof.

The laminate sheath 100 means a laminate sheath.

 The non-aqueous electrolyte secondary battery pack 10 according to the present embodiment relates to the provision of the discharging unit 10a outside the laminate non-aqueous electrolyte secondary battery.

However, the discharge unit 10a according to the present embodiment is not limited to a prismatic non-aqueous electrolyte secondary battery, but may be applied to a cylindrical non-aqueous electrolyte secondary battery or the like.

A non-aqueous electrolyte secondary battery is built in the laminate casing (100).

The material constituting the laminate sheath 100 is not particularly limited and may be applied to the laminate sheath 100 if the material is applicable to a laminate sheath of a lithium ion secondary battery.

The positive electrode current collecting tab 110 protrudes outside the laminated external body 100 and is connected to the positive electrode collector of the non-aqueous electrolyte secondary battery.

The negative electrode current collecting tab 120 protrudes outside the laminate sheath 100 and is connected to the negative electrode collector of the non-aqueous electrolyte secondary battery.

Hereinafter, a method of manufacturing the nonaqueous electrolyte secondary battery pack 10 will be described.

According to this embodiment, a method of manufacturing a nonaqueous electrolyte secondary battery is described as an example in which a lithium ion secondary battery is used as the nonaqueous electrolyte secondary battery.

The anode is fabricated as follows.

First, the cathode active material, the conductive agent, and the binder are mixed in a desired ratio and then dispersed in an organic solvent (for example, N-methyl-2-pyrrolidone) to form a slurry.

Further, the slurry is coated on the current collector 21 and dried to form a positive electrode active material layer.

Here, the method of applying the slurry is not particularly limited.

For example, the method of applying the slurry may be one of a knife coater method, a gravure coater method, and the like.

The following respective coating steps are also carried out by the same method.

Further, the positive electrode active material layer is pressed to a predetermined thickness by a press machine.

The anode is fabricated according to this embodiment in the manner described above.

At this time, the thickness of the positive electrode active material layer is not particularly limited and may be the same as the general thickness of the positive electrode active material layer of the lithium ion secondary battery.

Further, the positive electrode collector tab 110 is welded to the positive electrode collector.

The negative electrode according to this embodiment is also made the same as the positive electrode.

First, the negative electrode active material and the binder are mixed in the above ratio and then dispersed in an organic solvent (for example, N-methyl-2-pyrrolidone) to form a slurry.

Further, the slurry is coated on the current collector and dried to form a negative electrode active material layer.

Further, the negative electrode active material layer is pressed to a desired thickness by a press machine.

The negative electrode is fabricated in the same manner as described above.

Further, the negative electrode current collector tab 120 is welded to the negative electrode collector.

Further, a separator is placed between the positive electrode and the negative electrode to prepare an electrode structure sheet.

Further, the electrode structure is processed into a laminate shape.

For example, according to this embodiment, after the electrode structure sheet is wound, the wound electrode structure sheet is pressed to produce a winding element.

Then, the winding element is inserted into the laminated sheath 100.

Here, the winding element may be inserted into the laminate sheath 100 such that the positive electrode current collector tab 110 and the negative electrode current collector tab 120 protrude outside the laminate sheath 100.

Further, the portion other than the liquid injection portion of the laminate external body 100 is heat-welded.

Further, by injecting the electrolytic solution of the above composition into the laminate sheath 100 in the casting part, the electrolyte solution is impregnated into each pore in the separator.

Thus, the lithium ion secondary battery according to this embodiment is manufactured through a plurality of processes as described above.

Then, the previously prepared discharge unit 10a is mounted on the flat surface portion of the outside of the laminated external body 100. Then,

At this time, the metal plate for positive electrode connection 20, the insulator 40 and the metal plate for negative electrode connection 30 may be sequentially stacked on the planar portion of the outside of the laminated body 100.

The nonaqueous electrolyte secondary battery pack 10 is manufactured by connecting the positive electrode connection metal plate 20 and the positive electrode collector tab 110 and connecting the negative electrode connection metal plate 30 and the negative electrode collector tab 120 .

As described above, the nonaqueous electrolyte secondary battery pack 10 according to the present embodiment includes the discharging unit 10a.

The discharge unit 10a according to the present embodiment includes a metal plate 20 for cathode connection, a metal plate 30 for cathode connection, and an insulator 40. [

Therefore, according to the present embodiment, when the conductor passes through the nonaqueous electrolyte secondary battery pack 10, the first short circuit occurs between the positive electrode connection metal plate 20 and the negative electrode connection metal plate 30.

As a result, the battery voltage of the non-aqueous electrolyte secondary battery pack 10 is lowered by the first short-circuit between the positive electrode connection metal plate 20 and the negative electrode connection metal plate 30.

In addition, since the first short circuit occurs outside the non-aqueous electrolyte secondary battery, internal heat generation of the non-aqueous electrolyte secondary battery due to the first short circuit is suppressed.

On the other hand, according to Patent Documents 1 and 2, since the first short circuit is generated inside the non-aqueous electrolyte secondary battery, the possibility of the non-aqueous electrolyte secondary battery to generate heat due to the first short circuit is higher than in this embodiment.

Also, according to the present embodiment, since the conductor is heated as the battery voltage decreases after the first short circuit occurs, the insulator 40 is thermally shrunk by heat generation of the conductor.

An opening is formed in the insulator 40 by heat shrinkage of the insulator 40 and the metal plate for anode connection 20 and the metal plate for cathode connection 30 are brought into contact with each other.

Therefore, according to the present embodiment, the current flowing between the metal plate for positive electrode connection 20 and the metal plate for negative electrode connection 30 is increased, so that the drop rate of the battery voltage is increased.

On the other hand, after the conductor passes through the discharge unit 10a, it reaches the laminate sheath 100 and passes through the laminate sheath 100, and a short circuit occurs between the active materials in the conductor.

As described above, according to the present embodiment, the conductor penetrates the laminate external body 100 until a short circuit occurs between the active materials after the discharge unit 10a is short-circuited.

As a result, according to the present embodiment, it takes a certain time until a short circuit occurs between the active materials after the drop of the battery voltage starts.

That is, the time at which the shorting of the active materials starts is delayed by the time required for the conductor to pass through the laminated body 100 from the start of the drop of the battery voltage.

On the other hand, in Patent Documents 1 and 2, since the first short circuit occurs inside the non-aqueous electrolyte secondary battery, there is a problem that the time until the active materials short-circuit after the voltage drop of the battery starts is insufficient.

However, unlike Patent Documents 1 and 2, according to this embodiment, battery voltage can be greatly reduced when a short circuit occurs between active materials.

As a result, according to the present embodiment, heat generation due to the first short circuit is suppressed, and the battery voltage when the active materials are short-circuited can be significantly lowered, so that the safety of the non-aqueous electrolyte secondary battery can be improved.

(First Modification)

Various modifications of the embodiment will be described below.

In the first modification, the discharge unit 10a is disposed on both sides of the laminate external body 100. [

According to the first modified example, the above-described effect can be obtained even if the conductor penetrates through the both sides of the laminated sheath 100.

 (Second Modification)

In the second modification, at least one of the metal plate for positive electrode connection 20 and the metal plate for negative electrode connection 30 includes a plurality of metal plates for connecting positive electrodes or a plurality of metal plates for connecting negative electrodes.

Further, the metal plate for positive electrode connection 20 and the metal plate for negative electrode connection 30 are alternately stacked on the outside of the laminate external body 100.

An insulator 40 is disposed between the positive electrode connection metal plate 20 and the negative electrode connection metal plate 30 and each positive electrode connection metal plate 20 is connected to the positive electrode collector tab 110, The metal sheet 30 is connected to the negative electrode current collector tab 120. [

According to the second modification, since the non-aqueous electrolyte secondary battery can be discharged by more metal plates, the battery voltage can be significantly lowered when the active materials are short-circuited.

 (Third Modification)

3 is a side sectional view showing a modification of the embodiment of Fig. 1

Hereinafter, a third modification of the present invention will be described with reference to FIG.

3, the laminate sheath 100 according to the third modification includes an inner sheath 100a containing the non-aqueous electrolyte secondary battery 300 and an outer sheath 100b covering the inner sheath 100a 100b.

The discharge unit 10a is provided on the outer side of the inner casing 100a and the outer casing 100b is provided on the outer side of the discharge unit 10a.

The positive electrode connection metal plate 20 is connected to the positive electrode collector tab 110.

Here, as a method of connecting the positive electrode connection metal plate 20 and the positive electrode collector tab 110, an opening is formed to penetrate the outer casing 100b in the thickness direction, and the positive electrode connection metal plate 20, And the positive electrode collector tab 110 may be used.

The negative electrode connection metal plate 30 is connected to the negative electrode current collector tap 120.

A method of connecting the negative electrode metal plate 30 and the negative electrode current collector tab 120 is to connect the outer sheath 100b, the metal plate 20 for anode connection and the insulator 40 to the openings And connecting the negative electrode metal plate 30 and the negative electrode current collector tab 120 via this opening may be used.

It is also necessary to connect the negative electrode metal plate 30 and the negative electrode collector tab 120 so that the insulation between the metal plate for negative electrode 30 and the metal plate for positive electrode 20 is ensured.

According to the third modification, not only the above-described effect can be obtained, but also the non-aqueous electrolyte secondary battery pack 10 can be downsized.

Next, examples and comparative examples of this embodiment will be described.

 (Example 1)

First, a nonaqueous electrolyte secondary battery according to Example 1 was produced by the following process.

 (Preparation of anode)

Li ₂ CO ₃ and CoCO ₃ were mixed in a mortar so that the molar ratio of Li and Co was 1: 1, and then the mixture was heat-treated at 800 ° C for 24 hours in an air atmosphere.

Further, the product obtained by the heat treatment was pulverized to form LiCoO ₂ powder.

Further, polyvinylidene fluoride as the cathode active material powder, the carbon black powder and the positive electrode binder (binder) were used as the positive electrode active material powder prepared above, and each of them was mixed in a mass ratio of active material: conductive agent: binder of 96: 2: 2 The cathode mixture was prepared by dry mixing.

Further, the positive electrode mixture was dispersed in N-methyl-2-pyrrolidone to obtain a positive electrode mixture slurry.

Further, the positive electrode mixture slurry was coated on both sides of an aluminum foil having a thickness of 13 탆 as a positive electrode collector, dried, and then rolled.

Further, a positive electrode active material layer was formed on the current collector to prepare a positive electrode.

Here, the area density and filling density of the positive electrode active material layer were 45 mg / cm ² and 3.95 g / cc at the portions where the positive electrode active material layer was formed on both sides of the current collector.

(Preparation of negative electrode)

A negative electrode mixture was prepared by mixing carbon material (artificial graphite), CMC (carboxymethylcellulose sodium) and SBR (styrene butadiene rubber) in a mass ratio of 97.5: 1: 1.5.

Further, the negative electrode mixture was dispersed in water as a solvent to obtain a negative electrode mixture slurry.

Further, the negative electrode mixture slurry arrived on both sides of an 8 mu m-thick copper foil as an anode current collector, dried and rolled.

Thus, a negative electrode active material layer was formed on the current collector to prepare a negative electrode.

Here, the area density and filling density of the negative electrode active material layer on the current collector were 23 mg / cm ² and 1.60 g / cc at the portions where the negative electrode active material layer was formed on both sides of the current collector.

(Manufacture of a battery before injection molding)

The current collecting tabs were respectively welded to the positive electrode and the negative electrode slitted in a predetermined dimension.

A polyethylene microporous membrane separator (manufactured by Toray Industries, Inc., product number: F12BMS) for a lithium ion secondary battery was inserted between the positive electrode and the negative electrode to prepare an electrode structure sheet.

Further, the electrode structure sheet was wound and the wound electrode structure sheet was pressed to produce a flat-shaped wound element.

Further, the obtained flat-shaped winding element was housed in a laminated outer body made of a cup-formed aluminum laminate.

In addition, a portion of the opening of the laminate outer body other than the liquid portion was sealed by thermal welding to prepare a liquid electrolyte.

(Preparation of non-aqueous electrolytic solution)

The electrolytic solution was prepared by dissolving and mixing LiPF ₆ at a ratio of 1.0 mol / l and EC: EMC: DMC at a volume ratio of 3: 5: 2.

(Manufacture of battery)

A non-aqueous electrolyte was injected into the cell before the injection, and then the electrolyte solution was treated.

Then, the liquid injection portion was sealed by thermal welding to complete a non-aqueous electrolyte secondary battery having a design capacity of 1800 mAh.

(Connection of discharge unit)

Two aluminum foils having a thickness of 50 mu m and an insulator made of a polyethylene microporous film X having a thickness of 12 mu m (characteristics shown in Table 1) were interposed to form a discharge unit.

Further, the discharge unit is bonded to the flat portion of the aluminum laminate sheath by the double-sided tape, the aluminum foil constituting the discharge unit is connected to the positive electrode tab by ultrasonic welding, and the other aluminum foil is welded to the cathode tab by ultrasonic welding .

A non-aqueous electrolyte secondary battery pack according to Example 1 was produced in the same manner as described above.

Meanwhile, 20 non-aqueous electrolyte secondary battery packs were prepared for nail stabbing test.

The same is applied to the following Examples 2 to 5 and Comparative Examples 1 to 3.

(Example 2)

A non-aqueous electrolyte secondary battery pack according to Example 2 was produced in the same manner as in Example 1, except that the insulator was made of polyethylene microporous membrane Y having a thickness of 12 탆.

The characteristics of the polyethylene microporous membrane (Y) are shown in Table 1.

(Example 3)

A nonaqueous electrolyte secondary battery pack according to Example 3 was produced by the same process as in Example 1 except that the insulator was made of polyethylene microporous membrane (Z) having a thickness of 7 탆.

The characteristics of the polyethylene microporous membrane (Z) are shown in Table 1.

(Example 4)

A non-aqueous electrolyte secondary battery pack according to Example 4 was produced in the same manner as in Example 1, except that the aluminum foil of the discharge unit was made of an aluminum foil having a thickness of 200 탆.

(Example 5)

A non-aqueous electrolyte secondary battery pack according to Example 5 was fabricated in the same manner as in Example 1, except that the aluminum foil of the discharge unit was a copper foil having a thickness of 50 탆.

(Comparative Example 1)

The discharge unit was removed from Example 1 to prepare a non-aqueous electrolyte secondary battery pack of Comparative Example 1.

(Comparative Example 2)

A nonaqueous electrolyte secondary battery was fabricated by the same process as in Example 1.

Further, the back surface of an aluminum foil having a thickness of 50 mu m was bonded to the flat portion of the aluminum laminate external body by double-faced tape.

Further, the aluminum foil and the positive electrode tab were connected by ultrasonic welding.

Thus, a nonaqueous electrolyte secondary battery pack according to Comparative Example 2 was produced.

(Comparative Example 3)

First, a non-aqueous electrolyte secondary battery was produced by the same treatment as in Example 1. [

Further, the back surface of an aluminum foil having a thickness of 50 mu m was bonded to the flat portion of the aluminum laminate external body by double-faced tape.

Further, the aluminum foil and the negative electrode tab were connected by ultrasonic welding.

Thus, a non-aqueous electrolyte secondary battery pack according to Comparative Example 3 was produced.

(Measurement of Heat Shrinkage Rate of Micro-porous Film Made of Polyethylene)

On the other hand, a test sheet was prepared by cutting the polyethylene microporous membranes (X, Y, Z) to a size of 5 cm x cm each.

In addition, the test sheet was placed in a slide glass.

Both ends of the slide glass were fixed with a clip. In this state, the test sheet was heat-treated at 120 ° C for 10 minutes.

Then, the area shrinkage ratio of each test sheet was measured.

The results are shown in Table 1.

Made of polyethylene
The microporous membrane (X) Made of polyethylene
The microporous membrane (Y) Made of polyethylene
The microporous membrane (Z) Thickness (μm) 12 12 7 120 degree area shrinkage (%) 16.2 22.4 30.2

 (Nail sting test)

The non-aqueous electrolyte secondary battery packs of Examples 1 to 5 and Comparative Examples 1 to 3 were subjected to the following nail-sticking test.

More specifically, the nonaqueous electrolyte secondary battery pack was charged with CC-CV charging, that is, at a constant current (1800 mA) until the battery voltage reached 4.3 V, and then the constant current (4.3 V) Charged until.

After charging the non-aqueous electrolyte secondary battery pack, a nail having a diameter of 3 mm and a length of 50 mm was punched at the center of the non-aqueous electrolyte secondary battery pack to check whether the battery was ruptured or ignited.

Here, evaluation was carried out on 10 non-aqueous electrolyte secondary battery packs under two conditions of nail-sticking speed, and the results are shown in Table 2.

NG indicates that either rupture or ignition of the battery is confirmed.

 For example, " 9 / 10NG " indicates that either ignition or rupture has been confirmed in nine of the ten non-aqueous electrolyte secondary battery packs.

(Table 2) Nail stuck test result Nail polish test (piercing speed) 10mm / sec 50mm / sec Comparative Example 1 9/10 NG 4/10 NG Comparative Example 2 6/10 NG 2/10 NG Comparative Example 3 6/10 NG 3/10 NG Example 1 3/10 NG 0/10 NG Example 2 1/10 NG 0/10 NG Example 3 1/10 NG 0/10 NG Example 4 0/10 NG 0/10 NG Example 5 2/10 NG 0/10 NG

According to Table 2, by disposing the discharge unit on the outside of the laminate external body, the number of cells which are NG is reduced.

This is because the aluminum thin layer is short-circuited by the heat shrinkage of the polyethylene microporous membrane at 120 ° C, and the number of NG cells is reduced.

In Comparative Example 1 (a nonaqueous electrolyte secondary battery not provided with a discharge unit), if the battery is stuck to a nail, a short circuit occurs in the path of the positive electrode current collector-positive electrode active material layer-nail-negative electrode active material layer.

Since the active material layer has lower conductivity than the current collector made of metal, the resistance heat generation of the active material layer is larger than the resistance heat generation of the current collector.

Accordingly, the high-temperature active material and the electrolytic solution react with each other and the battery may be ruptured or ignited.

According to Comparative Examples 2 and 3 (nonaqueous electrolyte secondary battery having an aluminum foil electrically connected to the positive electrode tab or negative electrode tab), when the battery is nailed, the aluminum foil - the positive electrode collector arranged on the outside of the laminate enclosure - A short circuit occurs in the path of the layer-nail-anode active material layer.

Short-circuiting occurs between the aluminum foil and the positive electrode collector disposed on the outside of the laminate sheath before the positive electrode active material and the negative electrode active material are short-circuited, so that the resistance heat generation of the positive electrode active material and the negative electrode active material can be reduced.

However, the effect of reducing the resistance heat generation of the positive electrode active material and the negative electrode active material according to the above-described Patent Document 1 may not be sufficient as a safety measure.

That is, since the nail first reaches the winding element inside the battery and short-circuit occurs for the first time, the time for sufficiently lowering the battery voltage can not be secured, and resistance heat generation of the positive electrode active material and the negative electrode active material may not be sufficiently reduced.

On the other hand, according to Examples 1 to 5 (nonaqueous electrolyte secondary battery having a discharge unit), if the battery is stuck to the nail, the battery is short-circuited at the aluminum foil disposed outside the laminate external body, A short circuit occurs between the anode active material layers.

Therefore, since the battery voltage is sufficiently lowered when a short circuit occurs outside the laminate external body, the resistance heat generation of the cathode active material and the anode active material is less than in the case where a short circuit is generated in the laminate external body, .

In addition, the safety of the battery can be improved by increasing the heat shrinkage ratio of the microporous polyethylene made of the polyethylene sandwiched between the two aluminum foils disposed on the outside of the laminate casing.

That is, since the separator shrinks due to heat generated when a short circuit occurs in two aluminum foils, the short circuit area is widened, so that the battery voltage can be sufficiently lowered.

As described above, according to the present embodiment, when the conductor passes through the non-aqueous electrolyte secondary battery pack 10, a first short circuit is generated between the positive electrode connection metal plate 20 and the negative electrode connection metal plate 30.

Therefore, according to the present embodiment, the battery voltage is lowered by the first short circuit.

Further, since the first short circuit occurs outside the non-aqueous electrolyte secondary battery, the heat generation of the non-aqueous electrolyte secondary battery due to the first short circuit is suppressed.

Further, according to the present embodiment, the conductor penetrates the laminate external body 100 until the discharge unit 10a is short-circuited and the active materials are short-circuited.

Therefore, according to the present embodiment, the time taken for the active materials to short-circuit after the drop of the battery voltage starts is increased.

Therefore, according to this embodiment, the battery voltage when the active materials are short-circuited can be greatly reduced.

Therefore, according to this embodiment, the safety of the non-aqueous electrolyte secondary battery is further improved.

According to the present embodiment, the insulator 40 has heat shrinkability.

Therefore, the insulator 40 is thermally shrunk by heat generation of the conductor.

An opening is formed in the insulator 40 by heat shrinkage, and the anode connection metal plate 20 and the cathode connection metal plate 30 are brought into contact with each other via the opening.

Therefore, the current flowing between the positive electrode connection metal plate 20 and the negative electrode connection metal plate 30 is increased, and the drop rate of the battery voltage is increased.

The area shrinkage ratio of the insulator 40 at 120 DEG C is 16% or more.

As a result, the insulator 40 shrinks rapidly due to the heat generation of the conductor, so that the drop rate of the battery voltage is further improved.

The insulator 40 is made of one or more kinds of polymers selected from the group consisting of polyethylene, polypropylene, polyvinyl chloride, and mixtures thereof.

As a result, the insulator 40 shrinks rapidly due to the heat generation of the conductor, so that the drop rate of the battery voltage is further improved.

The metal plate for positive electrode connection 20 and the metal plate for negative electrode connection 30 are made of at least one kind of metal selected from the group consisting of copper, aluminum and their alloys.

As a result, the battery voltage is lowered more quickly when the metal plate is short-circuited.

The metal plate for positive electrode connection 20 and the metal plate for negative electrode connection 30 have a thickness of 0.05 mm to 1.0 mm.

As a result, while the light weight of the non-aqueous electrolyte secondary battery pack is maintained, the battery voltage is lowered more quickly at the time of short-circuiting between the metal plates.

In addition, in the second modification, since the positive electrode connection metal plate 20 and the negative electrode connection metal plate 30 are alternately stacked on the outside of the laminate sheath 100, the battery voltage can be lowered Goes.

In the third modification, since the discharge unit 10a is built in the laminate sheath 100, the nonaqueous electrolyte secondary battery pack 10 is miniaturized.

In addition, according to the present embodiment, since the discharge unit 10a is disposed in the laminate sheath 100, the safety of the laminate type secondary battery can be improved.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, And it goes without saying that the invention belongs to the scope of the invention.

10: Non-aqueous electrolyte secondary battery pack 20: Metal plate for positive electrode connection
30: metal plate for cathode connection 40: insulator
100: Laminate sheath 110: Positive electrode current collector tab
120: Negative current collector tab

Claims (8)

An outer shell having a non-aqueous electrolyte secondary battery built therein;
A positive electrode collector tab protruding outside the casing and connected to the positive electrode collector of the non-aqueous electrolyte secondary battery;
A negative electrode current collector tab protruding outside the casing and connected to the negative electrode collector of the non-aqueous electrolyte secondary battery;
A metal plate for positive electrode connection, which is provided outside the external body and connected to the positive electrode current collector tap;
A metal plate for connection to the negative electrode, which is provided outside the casing and connected to the negative current collector tab; And
And an insulator disposed between the positive electrode connection metal plate and the negative electrode connection metal plate. The method according to claim 1,
Wherein the insulator is heat-shrinkable. 3. The method of claim 2,
Wherein the insulator has an area shrinkage ratio at 120 ° C of 16% or more. 4. The method according to any one of claims 1 to 3,
Wherein the positive electrode connection metal plate and the negative electrode connection metal plate are made of one of copper, aluminum, and an alloy thereof. 5. The method of claim 4,
Wherein the metal plate for positive electrode connection and the metal plate for negative electrode connection have a thickness of 0.05 mm to 1.0 mm. The method according to claim 1,
Wherein the metal plate for positive electrode connection or the metal plate for negative electrode connection includes a plurality of metal plates for connecting positive electrodes or a plurality of metal plates for connecting negative electrodes,
Wherein the positive electrode connection metal plate and the negative electrode connection metal plate are alternately stacked on the outside of the outer casing. The method according to claim 1,
Wherein the outer body comprises an inner sheath housing the non-aqueous electrolyte secondary cell and an outer sheath covering the inner sheath,
The metal plate for anode connection, the metal plate for cathode connection, and the insulator are provided outside the inner casing,
Wherein the outer sheath is provided outside the metal plate for positive electrode connection, the metal plate for negative electrode connection, and the insulator. The method according to claim 1,
Wherein the outer body is a laminate type outer shell.

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