JP2001102016A - Lead wire for non-aqueous electrolyte cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lead wire for a non-aqueous electrolyte electric cell, that, in the non-aqueous electrolyte cell, can sufficiently ensure insulating property between a lead conductor and a metallic layer of an envelope. SOLUTION: The lead wire 18a for the non-aqueous electrolyte electric cell is fused on the inner surface of envelope 14. The envelope 14 has a metallic layer 22 therein and is filled with a non-aqueous electrolyte medium 20, a positive electrode 30, and a negative electrode 32. The lead wire 18a comprises a lead conductor 19a electrically connected to the positive electrode 30, and an insulator 21a cladding the lead conductor 19a and fused on the inner surface of the envelope 14. The insulator 21a includes at least a cross-linked layer 23a made of cross-linked polyolefin resin. According to this invention, as the insulator 21a includes the cross-linked layer 23a made of the cross-linked polyolefin resin, when the lead wire 18a is attached by thermal fusion, a short between the lead conductor 19a and the metallic layer 22 of envelope 14 is sufficiently prevented due to the fusion of the insulator.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lead wire used for a non-aqueous electrolyte battery as a power supply of an electronic device, and more particularly, to a bag for enclosing a positive electrode, a negative electrode, a non-aqueous electrolyte medium and the like. The present invention relates to a lead wire used for a non-aqueous electrolyte battery.

[0002]

2. Description of the Related Art In accordance with the demand for miniaturization of electronic devices, there is an increasing demand for miniaturization and weight reduction of batteries used as power sources for such devices. On the other hand, higher energy density and higher energy efficiency for batteries are also required. In order to satisfy such demands, expectations for a non-aqueous electrolyte battery (for example, a Li-ion battery or the like) in which an electrode, an electrolytic solution, and the like are sealed in a bag mainly made of a synthetic resin or the like are increasing.

In such a non-aqueous electrolyte battery, a lead wire generally extends from the bag to take out current, and the lead is attached to the bag as follows. That is, a part of the lead wire is inserted from the opening into the bag body having the opening, and the opening end portion is heat-sealed while the lead wire is sandwiched by the inner surface of the opening end portion of the bag body, and thus the lead wire is Is attached to the bag. In such a non-aqueous electrolyte battery, since the sealing performance of the bag determines the reliability of the battery, a bag having a structure in which a metal layer is sandwiched between plastic films is often used. .

Conventionally, as a lead wire used in such a non-aqueous electrolyte battery, for example, Japanese Unexamined Patent Publication No.
No. 7, Japanese Patent Application Laid-Open No. Sho 57-115820, as disclosed in Japanese Patent Application Laid-Open No. Hei 9-265974, and as disclosed in Japanese Patent Application Laid-Open No. 9-265974, a thermoplastic resin is used for the lead conductor. An insulator coated with an insulator is known.

[0005]

However, the above-mentioned Japanese Patent Application Laid-Open No. 3-62447 and Japanese Patent Application Laid-Open No. 57-1158
In the non-aqueous electrolyte battery described in Japanese Patent Application Publication No. 20-200, when the lead conductor is attached to the bag, the resin between the bag and the lead conductor is melted by heat fusion, and the lead conductor becomes a metal layer of the bag. Could be short-circuited. Also, in the nonaqueous electrolyte battery described in JP-A-9-265974, when the lead conductor is attached to the bag, the insulator between the lead conductor and the metal layer of the bag melts, and The conductor and the metal layer of the bag may be short-circuited.

Accordingly, it is an object of the present invention to provide a lead wire for a non-aqueous electrolyte battery which can ensure sufficient insulation between a lead conductor and a metal layer of a bag in a non-aqueous electrolyte battery.

[0007]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the present inventors have found that a lead conductor is covered with an insulator, and the insulator is a crosslinked layer made of a crosslinked polyolefin resin. By configuring to include
The present inventors have found that a short circuit between a lead conductor and a metal layer of a bag can be sufficiently prevented in a nonaqueous electrolyte battery, and have completed the present invention.

That is, the present invention relates to a lead wire for a non-aqueous electrolyte battery which includes a metal layer and is fused to the inner surface of a bag enclosing a non-aqueous electrolyte medium, a positive electrode and a negative electrode. A lead conductor that is electrically connected, and an insulator that covers the lead conductor and is fused to the inner surface of the bag body, wherein the insulator includes at least a crosslinked layer made of a crosslinked polyolefin resin.

According to the present invention, since the insulator includes a cross-linked layer made of a cross-linked polyolefin resin, when the lead wire is attached to the bag by heat fusion, the lead conductor and the metal of the bag are melted by the melting of the insulator. Short circuit between the layers is sufficiently prevented.

In the above lead wire, the insulator preferably includes a thermoplastic layer adhered to the lead conductor and made of a thermoplastic polyolefin resin. In this case, since the thermoplastic polyolefin resin has adhesiveness by heating, the adhesion between the lead conductor and the thermoplastic layer is ensured.

The adhesive strength of the thermoplastic layer to the lead conductor is preferably at least 4.9 N / cm. When the adhesive strength is less than 4.9 N / cm, when the non-aqueous electrolyte medium used for the non-aqueous electrolyte battery is a non-aqueous electrolyte, the electrolyte tends to leak from the bag.

The gel fraction of the crosslinked polyolefin resin is 20
It is preferably about 90%. If the gel fraction is less than 20%, the degree of cross-linking is insufficient and the cross-linked polyolefin resin is melted when the insulator of the lead wire is thermally fused to the inner surface of the bag, and the lead conductor and the metal layer of the bag are melted. And tend to short out. When the gel fraction exceeds 90%,
The degree of cross-linking is so large that the adhesiveness between the insulator and the bag deteriorates, and the electrolyte tends to leak in a non-aqueous electrolyte battery using a non-aqueous electrolyte as a non-aqueous electrolyte medium.

The crosslinked polyolefin resin is preferably crosslinked by irradiation with ionizing radiation from the viewpoint of productivity.

Further, the thermoplastic polyolefin resin is preferably one or a mixture of two or more selected from the group consisting of polyethylene, acid-modified polyethylene and ionomer. The above thermoplastic polyolefin resin,
It can be melted by heating and easily adhere to the lead conductor.

Further, it is preferable that the thermoplastic polyolefin resin is polypropylene or acid-modified polypropylene.

According to this lead wire, when fused to a bag made of polypropylene having excellent heat resistance as a material constituting the inner surface of the bag of the nonaqueous electrolyte battery, polyethylene or ethylene is used as the thermoplastic polyolefin resin. Compared with the case where a vinyl acetate copolymer is used, the adhesiveness between the insulator and the bag and the heat resistance of the nonaqueous electrolyte battery can be improved.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the lead wire for a non-aqueous electrolyte battery according to the present invention will be described below. In the drawings, the same or equivalent components are denoted by the same reference numerals.

FIG. 1 is a perspective view showing a preferred embodiment of the lead wire of the present invention. The lead wire of the present invention is incorporated in, for example, a thin nonaqueous electrolyte battery 10 as shown in FIG. The non-aqueous electrolyte battery 10 includes a single electrochemical cell including a non-aqueous electrolyte (non-aqueous electrolyte medium) in which an electrolyte (eg, a lithium compound) is dissolved in a non-aqueous solvent (eg, an organic solvent). Is sealed in a sealing bag (bag body) 14 in which a portion 12 to be heat-sealed and heat-sealed is formed. In this non-aqueous electrolyte battery 10, one ends of the first lead wire 18a and the second lead wire 18b extend upward from the upper part of the encapsulation bag 14 to enable electrical connection with the outside. The first lead wire 18
a and the second lead wire 18b have a first lead conductor 19a and a second lead conductor 19b, respectively, and their outer circumferences are covered with insulators 21a and 21b, respectively.

FIG. 2 is a sectional view of the non-aqueous electrolyte battery 10 shown in FIG.
It is sectional drawing along the A line or the BB line. As shown in FIG. 2, from the viewpoint of suppressing the permeation of the nonaqueous electrolytic solution 20, the sealing bag 14 is formed, for example, by sandwiching a metal foil or metal layer 22 made of aluminum with layers 24 to 28 made of a plastic layer. It consists of a formed multilayer film.

More specifically, the sealing bag 14 is formed by heat-sealing the periphery of the innermost layer 24 of the multilayer film that comes into contact with the non-aqueous electrolyte 20.
Here, the innermost layer 24 is the inner layer 2 of the multilayer film.
From the viewpoint of preventing the leakage of the non-aqueous electrolyte 20 in the heat seal portion 12 formed on the peripheral portion of the outer bag 4, for example, the outermost of the enclosing bag 14 is made of maleic acid-modified polyolefin (for example, maleic acid-modified low-density polyethylene). The layer 28 is provided to protect the metal layer 22 from damage, and is made of, for example, PET (polyethylene terephthalate).

The non-aqueous electrolyte 20 contained in the enclosing bag 14 is, for example, propylene carbonate, γ-
Organic solvents such as butyrolactone, LiClO ₄ , LiB
A solution in which a solute composed of a lithium compound such as F ₄ is dissolved is used. Further, a positive electrode plate 30 and a negative electrode plate 32 immersed in the non-aqueous electrolyte 20 are sealed in the sealing bag 14,
The positive electrode plate 30 and the negative electrode plate 32 are made of a metal base (not shown) made of a metal foil or expanded metal called a current collector, and an active material layer (not shown) formed on the metal base.
Consists of Further, a separator 34 for preventing diffusion of the non-aqueous electrolyte 20 is disposed between the positive electrode plate 30 and the negative electrode plate 32.

Further, the metal substrate of the positive electrode plate 30
6 through the first lead conductor 1 of the first lead wire 18a.
9a, and the other end of the first lead conductor 19a extends outside the encapsulation bag 14. The metal base material of the negative electrode plate 32 is also the second lead conductor 19b of the second lead wire 18b.
Of the second lead conductor 19b extends to the outside of the encapsulating bag 14. Also, a first lead conductor 19a and a second lead conductor 19b
Are covered by insulators 21a and 21b, respectively. Then, the first lead wire 18a and the second lead wire 18b are attached to the encapsulation bag 14 by thermally fusing the insulators 21a and 21b to the innermost layer 24 which is the inner surface of the encapsulation bag 14. I have.

Here, the first lead wire 18a and the second lead wire 18b will be described in detail.

As the first lead conductor 19a connected to the positive electrode plate 30, one that does not dissolve during discharge, for example, one made of aluminum, titanium, or an alloy thereof is preferably used. Further, as the second lead conductor 19b connected to the negative electrode plate 32, a precipitate such as lithium is generated at the time of overcharging, or a lithium alloy or the like is hardly formed and dissolved at the time of overdischarging where the potential difference becomes large. For example, nickel or copper or an alloy thereof is used.

The insulator 21a is connected to the first lead conductor 19a
And a thermoplastic layer 23a bonded to the outer periphery of the thermoplastic resin. The thermoplastic layer 23a is made of a thermoplastic polyolefin resin. As such a thermoplastic polyolefin resin, a resin that can be bonded to the first lead conductor 19a is used. Among them, the thermoplastic polyolefin resin tends to be melted by heating and to be more easily bonded to the first lead conductor 19a. Therefore, reactive resins such as polyethylene, acid-modified polyethylene, polypropylene, acid-modified polypropylene (for example, maleic anhydride-modified polypropylene), ionomers, and the like, or a mixture thereof are preferable. Here, when polypropylene having excellent heat resistance is used as a material of the innermost layer 24 of the enclosing bag 14, it is preferable to use polypropylene or acid-modified polypropylene among the above thermoplastic polyolefin resins. In this case, the adhesiveness between the insulators 21a and 21b and the innermost layer 24 of the encapsulating bag 14 is improved, as compared with the case where polyethylene or ethylene-vinyl acetate copolymer is used as the thermoplastic polyolefin resin. High heat resistance. In addition, as the above-mentioned ionomer, a homopolymer such as polyethylene or polypropylene or a copolymer obtained by cross-linking a copolymer such as ethylene and methacrylic acid with Na, Mg, K or the like is used.

The first lead conductor 1 of the thermoplastic layer 23a
The adhesive strength to 9a is preferably 4.9 N / cm or more. If the adhesive strength is less than 4.9 N / cm, the sealing property between the thermoplastic layer 23a and the first lead conductor 19a becomes insufficient, and the non-aqueous electrolyte 20 tends to leak out of the sealing bag 14. Here, the adhesive strength is the first lead conductor 1
The insulator 21a coated on the first lead conductor 19a
A force required to separate from the first lead conductor 19a, and is represented by a force per unit width (1 cm) of the first lead conductor 19a.

The insulator 21a includes a cross-linking layer 25a outside the thermoplastic layer 23a. The crosslinked layer 25a is made of a crosslinked polyolefin resin. The polyolefin resin may be any resin that can be heat-fused with the innermost layer 24 of the encapsulating bag 14, but it is preferable to use the same resin as the above-mentioned thermoplastic polyolefin resin. This is because, if a resin different from the above-mentioned thermoplastic polyolefin resin is used, the adhesive force between the thermoplastic layer 23a and the crosslinked layer 25a tends to decrease. Here, the sealing bag 14
When polypropylene having excellent heat resistance is used as the material constituting the innermost layer 24, it is preferable to use polypropylene or acid-modified polypropylene as the above-mentioned polyolefin resin. In this case, compared to the case where polyethylene or ethylene-vinyl acetate copolymer is used as the polyolefin resin, the insulators 21a and 21
The adhesiveness between b and the innermost layer 24 of the sealing bag 14 and the heat resistance of the nonaqueous electrolyte battery 10 are further improved.
As a method for crosslinking the polyolefin resin, crosslinking by irradiation with ionizing radiation such as an electron beam or gamma ray, chemical crosslinking by peroxide or the like, silane crosslinking, and the like are used. When the above polyolefin resin is crosslinked by ionizing radiation, a crosslinking assistant is added to the polyolefin resin as needed. As the crosslinking aid, for example, trimethylolpropane methacrylate, pentaerythritol triacrylate, ethyne glycol dimethacrylate, triallyl cyanurate, triallyl isocyanurate and the like are used. The cross-linked polyolefin resin has excellent heat deformation resistance even when heated to a temperature higher than its melting point. Further, even when the insulator 19a of the first lead wire 18a is thermally fused to the inner surface of the encapsulation bag 14, the first polyolefin resin can be used as the first polyolefin resin. Short circuit between the lead conductor 18a and the metal layer 22 of the sealing bag 14 can be sufficiently prevented.

The crosslinked polyolefin resin preferably has a gel fraction of 20% to 90%. The gel fraction is an index indicating the degree of crosslinking, and refers to the ratio of gel (insoluble polymer chains) in a crosslinked polyolefin resin insoluble in a solvent such as xylene. If the gel fraction is less than 20%, the degree of cross-linking is insufficient, and when the inner surface of the encapsulation bag 14 and the cross-linking layer 25a are thermally fused, the metal layer 22 of the encapsulation bag 14 and the first lead conductor 19a are not bonded. Tend to short out. On the other hand, if the gel fraction exceeds 90%, the degree of cross-linking is too large,
Adhesion between the non-aqueous electrolyte 5a and the non-aqueous electrolyte 20 tends to leak.

The insulator 21b coated on the second lead conductor 19b also has a thermoplastic layer 23b and a cross-linking layer 25b, and forms a thermoplastic polyolefin resin and a cross-linking layer 25b forming the thermoplastic layer 23b. As the crosslinked polyolefin resin, a thermoplastic polyolefin resin and a crosslinked polyolefin resin used in the insulator 19a are used, respectively.

Next, a method of manufacturing the first lead wire 18a will be described.

First, a first lead conductor 19a for a positive electrode plate having a rectangular cross section and made of, for example, aluminum is used.
Prepare On the other hand, the thermoplastic layer 2 made of a polyolefin resin such as maleic anhydride-modified low density polyethylene
3a and a cross-linked layer 25a made of a polyolefin resin such as low-density polyethylene.
Are produced using a T-die or an inflation extruder. And the crosslinked layer 25a
Crosslinking treatment is performed for the thermoplastic film to be constituted. As a method of the crosslinking treatment, irradiation crosslinking by ionizing radiation such as γ-ray or electron beam, chemical crosslinking by peroxide or the like, silane crosslinking, etc. are used. From the viewpoint of improving productivity, crosslinking is performed in a short time. Irradiation cross-linking is most preferred. And the crosslinked layer 25 thus obtained
The crosslinked thermoplastic film constituting a and the above-mentioned thermoplastic layer 23a are bonded to each other by thermal lamination to obtain an insulator 21a composed of two layers, a thermoplastic layer 23a and a crosslinked layer 25a.

Next, the insulator 21a thus obtained is
Is brought into close contact with the first lead conductor 19a with the thermoplastic layer 23a facing the first lead conductor 19a. Thereafter, the insulator 21a is heated and the thermoplastic layer 23a of the insulator 21a and the first
Is thermally fused with the lead conductor 19a. Thus, the first
Lead wire 18a is obtained.

The second lead 18b is also manufactured in the same manner as described above. However, the second lead wire 18b
Of the first lead conductor 19a
May be used, but for example, a material made of copper is preferably used.

The method of manufacturing the first lead wire 18a is not limited to the above-described method. For example, a one-layer thermoplastic film made of a polyolefin resin is prepared, and the thermoplastic film is heat-sealed to the first lead wire 19a. Then, the transmission distance from the outside of the thermoplastic film is smaller than the thickness of the film. By irradiating an electron beam controlled to be smaller, the first lead wire 19
a can be obtained. In this case, the portion of the thermoplastic film that has been exposed to the electron beam becomes the crosslinked layer 25a, and the portion that has not been exposed to the electron beam becomes the thermoplastic layer 23a.

Next, an example of a method of attaching the first lead wire 18a and the second lead wire 18b to the encapsulating bag 14 will be described.

The encapsulating bag 14 to which the first lead wire 18a and the second lead wire 18b are attached is manufactured as follows. That is, first, a pair of rectangular multilayer films including a layer made of maleic acid-modified polyolefin on the surface and a metal foil or a metal layer inside is prepared.
Next, these multilayer films were overlapped so that the layers of the maleic acid-modified polyolefin faced each other.
The sides are heat-sealed with a desired sealing width under a predetermined heating condition using a sealing machine. In this way, an enclosing bag 14 having an opening is obtained.

A part of the first lead wire 18a and a part of the second lead wire 18b are accommodated in the sealing bag 14 through the opening of the sealing bag 14. At this time, the insulator 21a of the first lead wire 18a and the insulator 21b of the second lead wire 18b are accommodated so as to be arranged between the innermost layers 24 of the enclosing bag 14, respectively. Then, the insulator 21a,
21b is sandwiched between the open ends of the enclosing bag 14, and the crosslinked layers 25a, 25b of the insulators 19a, 19b are sealed using a sealing machine.
25b and the innermost layer 24 of the encapsulating bag 14 are thermally fused. At this time, the insulating layers 19a and 19b are
a, 25b are included, and the insulating layers 21a, 21b are hardly melted. Therefore, heating between the first lead conductor 19a and the metal layer 22 of the encapsulation bag 14, and Short between the second lead conductor 19b and the metal layer 22 of the encapsulation bag 14 is sufficiently prevented.

The non-aqueous electrolyte battery to which the lead wire of the present invention is applied is not limited to the embodiment described above. That is, the nonaqueous electrolyte battery to which the lead wire of the present invention is applied is not particularly limited as long as the encapsulating bag includes a metal foil or a metal layer. For example, a solid electrolyte made of polyethylene oxide, polypropylene oxide, or the like may be used as the nonaqueous electrolyte medium of the nonaqueous electrolyte battery. As described above, even when the solid electrolyte is used as the non-aqueous electrolyte medium, in the non-aqueous electrolyte battery, the first lead conductor 19a, the second lead conductor 19b, and the sealing bag 1
4 is sufficiently prevented from being short-circuited with the fourth metal layer 22.

Hereinafter, the contents of the present invention will be described more specifically with reference to examples.

Example (Example 1) (Production of lead wire)

First, a first lead wire 18a for the positive electrode,
A second lead wire 18b for the negative electrode was manufactured. The first lead conductor 19a has a thickness of 0.1 mm and a width of 5 mm,
An aluminum plate having a length of 100 mm was prepared, and a copper plate having the same dimensions as the first lead conductor 19a was prepared as the second lead conductor 19b.

On the other hand, a maleic anhydride-modified low-density polyethylene film having a thickness of 50 μm (density: 0.92 g / c
m ³ , melt flow rate (MFR): 1.0 g / 10
min, melting point: 123 ° C.) and a low-density polyethylene film having a thickness of 50 μm (density: 0.92 g / cm ³ , M
FR: 1.0 g / 10 min, melting point: 123 ° C.), of which the low-density polyethylene film is irradiated with an electron beam at an accelerating voltage of 200 kV using an electron beam irradiation apparatus so that the absorbed dose becomes 30 kGy. Irradiated to crosslink. At this time, when the gel fraction of the crosslinked low density polyethylene was measured, the gel fraction was 25%. The MFR of the maleic anhydride-modified low-density polyethylene film and the low-density polyethylene film is JIS
K-6760 (test temperature: 190 ° C, load: 21.17)
N).

Then, the maleic anhydride-modified low density polyethylene film and the low density polyethylene film
Lamination was performed by heat lamination at 50 ° C.
Next, this laminated film was cut into 10 mm ×
Two 10 mm square insulators were obtained.

Thereafter, the two insulators 21a are overlapped so as to face each other via the first lead conductor 19a (FIG. 3).
(See FIG. 3A.) In this state, the insulator 21a was thermally fused to the first lead conductor 19a by hot pressing at 150 ° C. for 10 seconds (see FIG. 3B). Similarly, a second lead wire 18b was obtained. First lead conductor 19a and insulator 2
1a, the adhesive strength between the second lead conductor 19b and the insulator 21b was 5.4 N / cm.

The gel fraction of the low-density polyethylene was determined as follows. That is, low-density polyethylene was dissolved in a xylene solvent at 120 ° C. and allowed to stand for 24 hours, then the weight of the insoluble portion was measured, and the gel fraction was determined by the following equation. Gel fraction (%) = (insoluble weight / initial weight) × 100

The adhesive strength was determined as follows. That is, first, an aluminum plate having a thickness of 0.1 mm, a width of 5 mm, and a length of 100 mm was prepared. On the other hand, the above-mentioned laminated film was cut to have a width of 5 mm and a length of 50 mm.
Two rectangular insulators of mm were prepared. Then, the two insulators were overlapped so as to sandwich the aluminum plate. Thereafter, a portion having a length of 20 mm of the insulator was pressed and heat-sealed to obtain a sample for measuring the adhesive strength. Then, a portion of the insulator that was not pressed was held, and the insulator was pulled so as to be folded, and the strength at that time was obtained. (Preparation of sealed bag)

An aluminum laminate film having an aluminum layer 40 having a thickness of 25 μm and a polyethylene layer 42 having a thickness of 30 μm was cut to prepare two rectangular films 44 of 100 mm × 150 mm square. Thereafter, the two films 44 are overlapped with the surface of the polyethylene layer 42 facing inward, and heat sealed (150 ° C. × 1 minute) on three sides with a width of 5 mm, thus enclosing only one side with an opening. A bag 46 was obtained (see FIG. 4). (Production of simulated battery)

In the obtained enclosing bag 46, the volume ratio of ethylene carbonate / diethyl carbonate is 1/1.
After 5 cc of the mixed solvent is added, the obtained first lead wire 18a for the positive electrode and the second lead wire 18 for the negative electrode are obtained.
A part of b was set inside the enclosing bag 46. Then, the remaining one side of the enclosing bag 46 is connected to the first lead wire 18a and the second
In a state where the insulators 21a and 21b of the lead wire 18b were sandwiched, heat sealing was performed with a width of 5 mm to obtain a simulated battery 48 (see FIG. 5).

According to the above procedure, ten simulated batteries 48 were prepared.
For each of them, it was evaluated whether the insulation properties of the lead wires 18a and 18b were secured. Specifically, the aluminum layer 40 of the encapsulation bag 46 and the first lead conductor 19
a, It was determined whether or not a short circuit occurred between the second lead conductor 19b and the second lead conductor 19b by measuring the number of short circuits. Table 1 shows the results.

[Table 1]

As shown in Table 1, no short circuit occurred in the simulated battery according to this example. (Example 2)

When fabricating a cross-linked layer of the insulator of the first lead wire and the second lead wire, the amount of electron beam irradiation to the low-density polyethylene is adjusted so that the absorbed dose becomes 150 kGy, whereby the cross-linked low-density polyethylene is absorbed. Gel fraction of high density polyethylene of 8
A simulated battery was set to 10 in the same manner as in Example 1 except that it was set to 5%.
The first lead wire 18a and the second lead wire 18b were each evaluated for insulation. Table 1 shows the results. As shown in Table 1, no short circuit occurred in the simulated battery according to this example, as in Example 1. (Example 3)

When fabricating a crosslinked layer of the insulator of the first lead wire and the second lead wire, the low-density polyethylene is irradiated with an electron beam so that the absorbed dose is 20 kGy, whereby the low crosslinked low-density polyethylene is absorbed. Gel fraction of high density polyethylene is 17
%, And simulated batteries were manufactured in the same manner as in Example 1 except that the first lead wire 18a and the second
Of the lead wire 18b was evaluated. Table 1 shows the results.
Shown in As shown in Table 1, in the simulated battery according to the present example, a short circuit occurred in some cases, but the number was small. (Example 4)

The bridge layers 25a, 25b of the insulators 21a, 21b of the first lead wire 18a and the second lead wire 18b.
When preparing the same, the same procedure as in Example 1 was carried out except that the amount of electron beam irradiation on the low-density polyethylene was adjusted so that the absorbed dose was 200 kGy, so that the gel fraction of the crosslinked low-density polyethylene was 92%. Make 10 simulated batteries,
The insulation properties of the first lead wire 18a and the second lead wire 18b were evaluated for each. Table 1 shows the results.
As shown in Table 1, no short circuit occurred in the simulated battery according to this example. (Example 5)

By reducing the pressing time for hot pressing the insulators 21a and 21b to 5 seconds, the lead conductor 1
Ten simulated batteries were produced in the same manner as in Example 1 except that the bonding strength between the insulators 9a and 19b and the insulators 21a and 21b was 4.1 N / cm, and the first lead wires 18a and the second The insulation of the lead wire 18b was evaluated. Table 1 shows the results. As shown in Table 1, no short circuit occurred in the simulated battery according to this example, as in Example 1. (Example 6) (Production of lead wire)

As the first lead wire 18a for the positive electrode and the second lead wire 18b for the negative electrode, the same ones as in Example 1 were used.

On the other hand, a maleic anhydride-modified polypropylene film having a thickness of 50 μm (density: 0.89 g / c
m ³ , MFR: 2.8 g / 10 min, melting point: 140
C.) and a film made of a polypropylene mixture having a thickness of 50 μm. Here, the polypropylene mixture is a random type polypropylene (density: 0.9 g).
/ Cm ³ , MFR: 1.2 g / 10 min, melting point: 13
(0 ° C.) 1 part by weight of trimethylolpropane trimethacrylate was added to 100 parts by weight, and the mixture was mixed by a roll mixer. Further, a film composed of a polypropylene mixture was prepared by extruding the polypropylene mixture with a film extruder. In addition,
The maleic anhydride-modified polypropylene and polypropylene have an MFR of JIS K-6758 (test temperature: 23
0 ° C., load: 21.17 N).

Among these, the film made of the polypropylene mixture was cross-linked by irradiating an electron beam with an accelerating voltage of 200 kV using an electron beam irradiation apparatus so that the absorbed dose became 150 kGy. At this time, when the gel fraction of the film thus obtained was measured in the same manner as in Example 1, the gel fraction was 55%.

Then, two 10 mm × 10 mm square insulators were obtained in the same manner as in Example 1 except that the maleic anhydride-modified polypolypropylene film and the film made of the crosslinked polypropylene mixture were heat-laminated at 180 ° C. Was.

Thereafter, the first lead wire 18 was formed in the same manner as in Example 1 except that the thermal fusion between the two insulators 21a and the first lead conductor 19a was performed at 180 ° C. for 10 seconds.
a was produced. Similarly, a second lead wire 18b was manufactured. Then, the first lead conductor 19a and the insulator 21
a, The adhesive strength between the second lead conductor 19b and the insulator 21b was measured in the same manner as in Example 1, and was 4.9 N / cm. (Preparation of sealed bag)

In place of the polyethylene layer 42 having a thickness of 30 μm, an aluminum laminated film having a polypropylene layer having a thickness of 30 μm is prepared, and two rectangular films 44 cut out from the aluminum laminated film and superposed are provided.
In the same manner as in Example 1 except that the three sides were heat-sealed at 180 ° C., an enclosing bag 46 having only one side open was obtained. (Production of simulated battery)

Using the thus obtained first lead wire 18a for the positive electrode, the second lead wire 18b for the negative electrode, and the encapsulating bag 46, a simulated battery 48 was prepared in the same manner as in Example 1.
This was produced. Then, for each of the simulated batteries 48, whether or not the insulation of the lead wires 18a and 18b was ensured was evaluated in the same manner as in Example 1. Table 1 shows the results. As shown in Table 1, no short circuit occurred in the simulated battery according to this example, as in Example 1. (Example 7)

Instead of the polypropylene in the polypropylene mixture, maleic anhydride-modified polypropylene (density:
0.89 g / cm ³ , MFR: 2.8 g / 10 min,
Ten simulated batteries were produced in the same manner as in Example 6 except that the melting point was 140 ° C.). In addition, the first lead conductor 1
9a, insulator 21 covering second lead conductor 19b
When the gel fraction of each of the crosslinked maleic anhydride-modified polypropylene films of a and 21b was measured in the same manner as in Example 1, the gel fraction was 62%. Further, the first lead conductor 19a and the insulator 21
a, The adhesive strength between the second lead conductor 19b and the insulator 21b was measured in the same manner as in Example 1, and was 4.9 N / cm.

Then, the simulated battery 1 obtained as described above
For each of 0, the insulation properties of the first lead wire 18a and the second lead wire 18b were evaluated in the same manner as in Example 1. Table 1 shows the results. As shown in Table 1, no short circuit occurred in the simulated battery according to this example, as in Example 1.

[0063]

As described above, according to the present invention, since the insulator includes the cross-linked layer made of the cross-linked polyolefin resin, when the lead wire is attached to the bag body by heat fusion, the insulator is melted. Short circuit between the lead conductor and the metal layer of the bag is sufficiently prevented, and the insulation of the lead wire can be sufficiently ensured.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a nonaqueous electrolyte battery to which a lead wire for a nonaqueous electrolyte battery of the present invention is applied.

FIG. 2 is a sectional view taken along line AA or BB in FIG. 1;

FIG. 3A is a plan view illustrating a first lead wire according to the first embodiment, and FIG. 3B is a cross-sectional view of the first lead wire.

FIG. 4 is a vertical cross-sectional view of the sealing bag according to the first embodiment.

FIG. 5 is a front view of the simulation battery according to the first embodiment.

[Explanation of symbols]

14: Bag body, 18a, 18b: Lead wire for non-aqueous electrolyte battery, 19a, 19b: Lead conductor, 20: Non-aqueous electrolyte medium, 21a, 21b: Insulator, 22: Metal layer, 23a,
23b: thermoplastic layer, 25a, 25b: crosslinked layer, 30: positive electrode, 32: negative electrode.

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[Procedure amendment]

[Submission date] July 24, 2000 (2007.2
4)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0007

[Correction method] Change

[Correction contents]

[0007]

Means for Solving the Problems The inventors of the present invention have made intensive studies to achieve the above object, and as a result, covered a lead conductor with an insulator, and the insulator was crosslinked with a predetermined gel fraction. By comprising a crosslinked layer made of a polyolefin resin and a thermoplastic layer made of a thermoplastic polyolefin resin, it is possible to sufficiently prevent a short circuit between the lead conductor and the metal layer of the bag in a nonaqueous electrolyte battery. At the same time, they have found that the adhesion between the lead conductor and the insulator and the adhesion between the insulator and the bag can be ensured to prevent the leakage of the electrolytic solution, thereby completing the present invention.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction contents]

That is, the present invention relates to a lead wire for a non-aqueous electrolyte battery which includes a metal layer and is fused to the inner surface of a bag enclosing a non-aqueous electrolyte medium, a positive electrode and a negative electrode. A lead conductor that is electrically connected, and an insulator that covers the lead conductor and is fused to the inner surface of the bag body, and the insulator is made of a crosslinked polyolefin resin having a gel fraction of 20 to 90%. It is characterized by including a crosslinked layer and a thermoplastic layer adhered to the lead conductor and made of a thermoplastic polyolefin resin.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction contents]

According to the present invention, the gel fraction is 20 to 90%
Since the insulator includes a cross-linked layer made of a cross-linked polyolefin resin, when the lead wire is attached to the bag by heat fusion, a short circuit occurs between the lead conductor and the metal layer of the bag due to the melting of the insulator. In addition to being sufficiently prevented, adhesion between the insulator and the bag is ensured, and leakage of the electrolyte is prevented.

[Procedure amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction contents]

In the above lead wire, the insulator includes a thermoplastic layer adhered to the lead conductor and made of a thermoplastic polyolefin resin. Since the thermoplastic polyolefin resin has adhesiveness by heating, the adhesiveness between the lead conductor and the thermoplastic layer is ensured.

[Procedure amendment 6]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction contents]

The gel fraction of the crosslinked polyolefin resin is 20
It needs to be ~ 90%. If the gel fraction is less than 20%, the degree of cross-linking is insufficient and the cross-linked polyolefin resin is melted when the insulator of the lead wire is thermally fused to the inner surface of the bag, and the lead conductor and the metal layer of the bag are melted. And tend to short out. On the other hand, when the gel fraction exceeds 90%, the degree of crosslinking is too large, and the adhesion between the insulator and the bag deteriorates. In a non-aqueous electrolyte battery using a non-aqueous electrolyte as a non-aqueous electrolyte medium, Electrolyte leakage tends to occur.

[Procedure amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0013

[Correction method] Change

[Correction contents]

Such a crosslinked polyolefin resin is preferably crosslinked by irradiation with ionizing radiation from the viewpoint of productivity. Further, it is preferable that the crosslinked layer is made of a crosslinked polyolefin resin obtained by irradiating ionizing radiation to the same resin as the thermoplastic polyolefin resin constituting the thermoplastic layer to crosslink.

[Procedure amendment 8]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction contents]

Further, the polyolefin resin is preferably one or a mixture of two or more selected from the group consisting of polyethylene, acid-modified polyethylene and ionomer. The above thermoplastic polyolefin resin can be melted by heating and easily adhere to the lead conductor.

[Procedure amendment 9]

[Document name to be amended] Statement

[Correction target item name] 0015

[Correction method] Change

[Correction contents]

Preferably, the polyolefin resin is polypropylene or acid-modified polypropylene.

[Procedure amendment 10]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction contents]

According to this lead wire, when fused to a bag made of polypropylene having excellent heat resistance as a material constituting the inner surface of the bag of the nonaqueous electrolyte battery, polyethylene or ethylene vinyl acetate is used as the polyolefin resin. As compared with the case where a copolymer is used, the adhesiveness between the insulator and the bag and the heat resistance of the nonaqueous electrolyte battery can be improved. Therefore, when the bag to which the lead wire for a non-electrolyte battery is to be fused has an inner layer made of polypropylene, the crosslinked polyolefin resin is a crosslinked polypropylene or a crosslinked acid-modified polypropylene, and a thermoplastic polyolefin. Preferably, the resin is polypropylene or acid-modified polypropylene.

[Procedure amendment 11]

[Document name to be amended] Statement

[Correction target item name] 0028

[Correction method] Change

[Correction contents]

The crosslinked polyolefin resin must have a gel fraction of 20% to 90%. The gel fraction is an index indicating the degree of crosslinking, and refers to the ratio of gel (insoluble polymer chains) in a crosslinked polyolefin resin insoluble in a solvent such as xylene. If the gel fraction is less than 20%, the degree of crosslinking is insufficient,
When the inner surface of the encapsulation bag 14 and the cross-linking layer 25a are thermally fused, the metal layer 22 of the encapsulation bag 14 and the first lead conductor 19a tend to be short-circuited. On the other hand, when the gel fraction exceeds 90%, the degree of crosslinking is too large, the adhesion between the encapsulating bag 14 and the crosslinked layer 25a is deteriorated, and the nonaqueous electrolyte 20 tends to leak.

[Procedure amendment 12]

[Document name to be amended] Statement

[Correction target item name] 0029

[Correction method] Change

[Correction contents]

The insulator 21b coated on the second lead conductor 19b also has a thermoplastic layer 23b and a cross-linking layer 25b, and forms a thermoplastic polyolefin resin and a cross-linking layer 25b forming the thermoplastic layer 23b. As the crosslinked polyolefin resin, a thermoplastic polyolefin resin and a crosslinked polyolefin resin used in the insulator 21a are used, respectively.

[Procedure amendment 13]

[Document name to be amended] Statement

[Correction target item name] 0048

[Correction method] Change

[Correction contents]

According to the above procedure, ten simulated batteries 48 were prepared.
For each of them, it was evaluated whether the insulation properties of the lead wires 18a and 18b were secured. Specifically, the aluminum layer 40 of the encapsulation bag 46 and the first lead conductor 19
a, It was determined whether or not a short circuit occurred between the second lead conductor 19b and the second lead conductor 19b by measuring the number of short circuits. Table 1 shows the results.

[Table 1]

[Procedure amendment 14]

[Document name to be amended] Statement

[Correction target item name] 0050

[Correction method] Change

[Correction contents]

When fabricating a cross-linked layer of the insulator of the first lead wire and the second lead wire, the amount of electron beam irradiation to the low-density polyethylene is adjusted so that the absorbed dose becomes 150 kGy, whereby the cross-linked low-density polyethylene is absorbed. Gel fraction of high density polyethylene of 8
A simulated battery was set to 10 in the same manner as in Example 1 except that it was set to 5%.
The first lead wire 18a and the second lead wire 18b were each evaluated for insulation. Table 1 shows the results. As shown in Table 1, no short circuit occurred in the simulated battery according to this example, as in Example 1. (Comparative Example 1)

[Procedure amendment 15]

[Document name to be amended] Statement

[Correction target item name] 0051

[Correction method] Change

[Correction contents]

When fabricating a crosslinked layer of the insulator of the first lead wire and the second lead wire, the low-density polyethylene is irradiated with an electron beam so that the absorbed dose is 20 kGy, whereby the low crosslinked low-density polyethylene is absorbed. Gel fraction of high density polyethylene is 17
%, And simulated batteries were manufactured in the same manner as in Example 1 except that the first lead wire 18a and the second
Of the lead wire 18b was evaluated. Table 1 shows the results.
Shown in As shown in Table 1, the simulated battery according to the present comparative example sometimes had a short circuit. (Comparative Example 2)

[Procedure amendment 16]

[Document name to be amended] Statement

[Correction target item name] 0052

[Correction method] Change

[Correction contents]

The bridge layers 25a, 25b of the insulators 21a, 21b of the first lead wire 18a and the second lead wire 18b.
When preparing the same, the same procedure as in Example 1 was carried out except that the amount of electron beam irradiation on the low-density polyethylene was adjusted so that the absorbed dose was 200 kGy, so that the gel fraction of the crosslinked low-density polyethylene was 92%. Make 10 simulated batteries,
The insulation properties of the first lead wire 18a and the second lead wire 18b were evaluated for each. Table 1 shows the results.
As shown in Table 1, no short circuit occurred in the simulated battery according to this comparative example, but the adhesive strength between the crosslinked layer and the enclosing bag was 3.4 N / cm. (Example 3)

[Procedure amendment 17]

[Document name to be amended] Statement

[Correction target item name] 0053

[Correction method] Change

[Correction contents]

By reducing the pressing time for hot pressing the insulators 21a and 21b to 5 seconds, the lead conductor 1
Ten simulated batteries were produced in the same manner as in Example 1 except that the bonding strength between the insulators 9a and 19b and the insulators 21a and 21b was 4.1 N / cm, and the first lead wires 18a and the second The insulation of the lead wire 18b was evaluated. Table 1 shows the results. As shown in Table 1, no short circuit occurred in the simulated battery according to this example, as in Example 1. (Example 4) (Production of lead wire)

[Procedure amendment 18]

[Document name to be amended] Statement

[Correction target item name] 0060

[Correction method] Change

[Correction contents]

Using the thus obtained first lead wire 18a for the positive electrode, the second lead wire 18b for the negative electrode, and the encapsulating bag 46, a simulated battery 48 was prepared in the same manner as in Example 1.
This was produced. Then, for each of the simulated batteries 48, whether or not the insulation of the lead wires 18a and 18b was ensured was evaluated in the same manner as in Example 1. Table 1 shows the results. As shown in Table 1, no short circuit occurred in the simulated battery according to this example, as in Example 1. (Example 5)

[Procedure amendment 19]

[Document name to be amended] Statement

[Correction target item name] 0061

[Correction method] Change

[Correction contents]

Instead of the polypropylene in the polypropylene mixture, maleic anhydride-modified polypropylene (density:
0.89 g / cm ³ , MFR: 2.8 g / 10 min,
Ten simulated batteries were produced in the same manner as in Example 4 except that the melting point was 140 ° C.). In addition, the first lead conductor 1
9a, insulator 21 covering second lead conductor 19b
When the gel fraction of each of the crosslinked maleic anhydride-modified polypropylene films of a and 21b was measured in the same manner as in Example 1, the gel fraction was 62%. Further, the first lead conductor 19a and the insulator 21
a, The adhesive strength between the second lead conductor 19b and the insulator 21b was measured in the same manner as in Example 1, and was 4.9 N / cm.

[Procedure amendment 20]

[Document name to be amended] Statement

[Correction target item name] 0063

[Correction method] Change

[Correction contents]

[0063]

As described above, according to the present invention, the insulator comprises a cross-linked layer made of a cross-linked polyolefin resin having a gel fraction of 20 to 90%, and a cross-linked layer made of a thermoplastic polyolefin resin adhered to a lead conductor. When the lead wire is attached to the bag body by thermal fusion, a short circuit between the lead conductor and the metal layer of the bag body due to melting of the insulator is sufficiently prevented, and the lead wire Can be sufficiently ensured, and the adhesion between the lead conductor and the insulator and the adhesion between the insulator and the bag can be ensured to prevent leakage of the electrolyte.

 ────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Satoshi Sukushima 1-3-1 Shimaya, Konohana-ku, Osaka-shi, Osaka F-term in Sumitomo Electric Industries, Ltd. Osaka Works 5H011 EE04 FF04 GG01 HH02 KK00 KK05 5H022 AA09 CC11 EE06 KK03 5H024 CC04 DD11 EE09 5H029 AJ12 DJ05

Claims (7)

[Claims] 1. A lead wire for a non-aqueous electrolyte battery including a metal layer and fused to an inner surface of a bag body enclosing a non-aqueous electrolyte medium, a positive electrode and a negative electrode, wherein the lead wire is electrically connected to the positive electrode or the negative electrode. A lead conductor to be connected, an insulator covering the lead conductor and being fused to the inner surface of the bag body, wherein the insulator includes a cross-linked layer made of a cross-linked polyolefin resin. Lead wire for water electrolyte battery. 2. The lead wire for a non-aqueous electrolyte battery according to claim 1, wherein the insulator includes a thermoplastic layer adhered to the lead conductor and made of a thermoplastic polyolefin resin. 3. The lead wire for a non-aqueous electrolyte battery according to claim 2, wherein the adhesive strength of the thermoplastic layer to the lead conductor is 4.9 N / cm or more. 4. The lead wire for a non-aqueous electrolyte battery according to claim 1, wherein the gel fraction of the crosslinked polyolefin resin is 20 to 90%. 5. The non-aqueous electrolyte battery lead wire according to claim 1, wherein the cross-linked polyolefin resin is cross-linked by irradiation with ionizing radiation. 6. The thermoplastic polyolefin resin according to claim 2, wherein the thermoplastic polyolefin resin is one or a mixture of two or more selected from the group consisting of polyethylene, acid-modified polyethylene and ionomer. The lead wire for a non-aqueous electrolyte battery according to the above. 7. The lead wire for a non-electrolyte battery according to claim 2, wherein the thermoplastic polyolefin resin is polypropylene or acid-modified polypropylene.