KR20190101482A - Lead wire for nonaqueous electrolyte battery and nonaqueous electrolyte battery having same - Google Patents

Abstract

A lead wire for a nonaqueous electrolyte battery having a lead conductor, a first insulating layer directly covering at least a portion of the lead conductor, and a second insulating layer covering the first insulating layer, wherein the second insulating layer is an olefin crystal. A lead wire for nonaqueous electrolyte batteries, which is a crosslinked product of an ethylene octene-olefin crystal block polymer and a resin composition containing polypropylene in a mass ratio of 10:90 to 40:60.

Description

Lead wire for nonaqueous electrolyte battery and nonaqueous electrolyte battery having same

The present disclosure relates to a lead wire for a nonaqueous electrolyte battery and a nonaqueous electrolyte battery having the same. This application claims priority based on Japanese Patent Application No. 2017-235005 for which it applied on December 7, 2017, and uses all the description of the said Japanese application.

With miniaturization and weight reduction of electronic devices, miniaturization and weight reduction are required for electric parts such as batteries and capacitors used in these devices. For this reason, the nonaqueous electrolyte battery which uses the sealing body as a sealing container, for example, and encloses a nonaqueous electrolyte (electrolyte solution), a positive electrode, and a negative electrode in its inside is employ | adopted. As the nonaqueous electrolyte, an electrolyte solution in which lithium salts containing fluorine such as LiPF ₆ and LiBF ₄ are dissolved in propylene carbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate and the like is used.

The sealed container is required to have a property of preventing permeation of electrolyte or gas and penetration of moisture from the outside. For this reason, the laminated film which coat | covered metal layers, such as aluminum foil, with resin is used as a material of a sealing container, and the edge part of two laminate films is heat-sealed, and a sealing container is formed.

One end of the sealing container is an opening, and a nonaqueous electrolyte, a positive electrode plate, a negative electrode plate, a separator, and the like are sealed therein. Moreover, the lead conductor which one end connected to the positive electrode plate and the negative electrode plate is arrange | positioned so that it may extend outward from the inside of a sealing container, and finally the opening part of a sealing container will be closed by heat-sealing (heat-sealing) an opening, and a sealing container and a lead conductor To seal the opening. This last heat-sealed portion is called a sealing portion.

The part corresponding to the sealing part of a lead conductor is coat | covered with the insulating layer, and what provided with the insulating layer and the lead conductor is called the lead wire for nonaqueous electrolyte batteries. The sealed container and the lead conductor are bonded (heat-sealed) through this insulating layer. Therefore, this insulating layer is required to have a property of maintaining adhesion between the lead conductor and the sealed container without generating a short circuit between the metal layer of the sealed container and the lead conductor.

Patent Literature 1 discloses a lead wire for a nonaqueous electrolyte battery having an insulating layer having a two-layer structure and including a crosslinking layer made of a crosslinked polyolefin resin having a gel fraction of 20 to 90% and a thermoplastic layer made of a thermoplastic polyolefin resin. It is. Since the crosslinking layer which consists of a crosslinking olefin resin whose gel fraction is 20 to 90% has a high melting point, it can prevent the short circuit between the lead conductor and the metal layer by melting of an insulator at the time of thermal fusion. In addition, since the thermoplastic layer made of thermoplastic polyolefin has high adhesiveness with the conductor, the thermoplastic layer is melted at the time of thermal fusion to ensure the adhesiveness between the conductor and the encapsulation body, and leakage of the electrolyte solution is prevented.

Patent Literature 2 discloses a lead member having a pair of insulating films attached to both sides of a lead conductor, wherein the insulating film has a two-layer structure of a crosslinking layer and an adhesive layer. The crosslinking layer uses polypropylene as the base resin and contains 0.5 wt% or more and 10 wt% or less of crosslinking aids. The adhesive layer has a polypropylene resin having a melt flow rate of 4 g / 10 minutes or more and 7 g / 10 minutes or less as a base resin.

Japanese Patent Laid-Open No. 2001-102016 Japanese Patent Laid-Open No. 2011-103245

A lead wire according to one aspect of the present disclosure is a lead wire for a nonaqueous electrolyte battery having a lead conductor, a first insulation layer directly covering at least a portion of the lead conductor, and a second insulation layer covering the first insulation layer, The said 2nd insulating layer is a lead wire for nonaqueous electrolyte batteries which is a crosslinked body of an olefin crystal ethylene octene olefin crystal block polymer, and the resin composition which contains a polypropylene by mass ratio 10: 90-40: 60.

A nonaqueous electrolyte battery according to another aspect of the present disclosure is a nonaqueous electrolyte battery including the lead wire for the nonaqueous electrolyte battery.

1 is a front view of a nonaqueous electrolyte battery according to one embodiment of the present disclosure.
2 is a partial cross-sectional view of a nonaqueous electrolyte battery according to one embodiment of the present disclosure.
3 is a partial cross-sectional view of a lead wire according to one embodiment of the present disclosure.

[Problem that this disclosure is about to solve]

As described in Patent Literature 1 and Patent Literature 2, in a lead wire for a nonaqueous electrolyte battery, a short-circuit between the metal layer and the lead conductor of the encapsulation container can be prevented at the time of thermal fusion by using a crosslinking layer as part of the insulating layer. As a crosslinking layer, the crosslinked body of polypropylene is used normally.

Since polypropylene is a material which is difficult to crosslink compared with polyethylene, it is mixed and used with a crosslinking adjuvant as described in patent document 2. Specifically, the mixture of the polypropylene and the crosslinking aid is molded into a sheet, and then crosslinked by irradiation with an electron beam or the like. Since crosslinking adjuvant has low molecular weight, melting | fusing point is low and may volatilize by the heat at the time of shaping | molding process. The volatilized vapor of the crosslinking aid is cooled in a separate place of the molding facility and adhered to the molding facility or the product, which may adversely affect the product. This is not the case when the amount of the crosslinking aid is reduced. However, the crosslinking of the polypropylene is insufficient, and the metal layer and the lead conductor of the encapsulation container are thermally fused between the lead wire and the encapsulation container during the manufacture of the nonaqueous electrolyte battery. There is a possibility of short circuit.

Therefore, the present disclosure can be manufactured without adversely affecting molding equipment and products, and can maintain the adhesiveness between the lead conductor and the encapsulation container without causing a short circuit between the metal layer of the encapsulation container and the lead conductor. An object of the present invention is to provide a lead wire and a nonaqueous electrolyte battery having the same.

[Effect of this disclosure]

According to the present disclosure, a nonaqueous electrolyte battery can be manufactured without adversely affecting a molding facility or a product, and can maintain adhesion between the lead conductor and the sealed container without generating a short circuit between the metal layer of the sealed container and the lead conductor. A lead wire and a nonaqueous electrolyte battery having the same can be provided.

Description of Embodiments of the Present Disclosure

A nonaqueous electrolyte battery lead wire according to one embodiment of the present disclosure has a lead conductor, a first insulating layer directly covering at least a portion of the lead conductor, and a second insulating layer covering the first insulating layer. As a lead wire, a said 2nd insulating layer is a crosslinked body of an olefin crystal ethylene octene olefin crystal block polymer, and the resin composition which contains polypropylene by mass ratio 10: 90-40: 60. According to this aspect, it can manufacture without adversely affecting a molding facility or a product, and can maintain the adhesiveness of a lead conductor and a sealing container, without generating the short circuit of the metal layer of a sealing container and a lead conductor.

In another embodiment of the present disclosure, the difference between the melting point of the olefin crystal, ethylene octene and olefin crystal block polymer and the melting point of the polypropylene is 50 ° C. or less. According to this aspect, film formability improves because the compatibility of resins improves.

In another embodiment of the present disclosure, the first insulating layer includes an acid-modified polyolefin. According to this aspect, the adhesiveness of a 1st insulating layer and a metal improves.

In another embodiment of the present disclosure, the polypropylene is random polypropylene or acid-modified polypropylene. According to this aspect, the compatibility of the olefin crystal ethylene octene olefin crystal block polymer with the polypropylene is excellent.

In other embodiment of this indication, the thickness of the sum total of a said 1st insulating layer and a said 2nd insulating layer is 30 micrometers or more and 200 micrometers or less.

In another embodiment of the present disclosure, the acid modified polyolefin is maleic anhydride modified polyolefin. According to this aspect, the adhesiveness of a 1st insulating layer and a metal improves.

In another embodiment of the present disclosure, the first insulating layer includes maleic anhydride modified polyolefin, and the polypropylene is random polypropylene or acid-modified polypropylene. According to this aspect, the adhesiveness of a 1st insulating layer and a metal improves, and it is excellent in the compatibility of the said olefin crystal ethylene octene olefin crystal block polymer with the said polypropylene.

Another embodiment of the present disclosure is a nonaqueous electrolyte battery including the lead wire for the nonaqueous electrolyte battery. According to this aspect, the lead wire can be produced without adversely affecting the molding equipment and the product, and the adhesiveness of the lead conductor and the sealed container can be maintained without generating a short circuit between the metal layer and the lead conductor of the sealed container.

[Details of Embodiments of the Present Disclosure]

FIG. 1 is a front view schematically showing an embodiment of a nonaqueous electrolyte battery, and FIG. 2 is a partial cross sectional view taken along the line AA ′ of FIG. 1. This nonaqueous electrolyte battery 1 has a substantially rectangular sealed container 2 and a lead conductor 3 extending from the inside of the sealed container 2 to the outside. The lead conductor 3 and the sealing container 2 are connected by the sealing part 9 via the 1st insulating layer 4b and the 2nd insulating layer 4a.

As shown in FIG. 2, the sealing container 2 consists of the metal layer 5, the resin layer 6 which coat | covers the metal layer 5, and the laminated film 8 of three layers which consist of the resin layer 7. . The metal layer 5 is formed of metal, such as aluminum foil. As the resin layer 6 located outside the sealing container, polyamide resins such as 6,6-nylon and 6-nylon, polyester resins, polyimide resins, and the like can be used. Moreover, it is preferable to use the insulating resin which does not melt | dissolve in a nonaqueous electrolyte, and heats and melt | dissolves in the resin layer 7 located inside the sealing container 2, A polyolefin resin, an acid-modified polyolefin resin, and an acid-modified styrene Len-based elastomers are exemplified. The encapsulation container 2 superimposes two laminate films 8, and heat-excludes three sides other than the side which a lead conductor penetrates, and is produced. In the outer peripheral part of the sealing container, the two metal layers 5 are bonded through the resin layer 7.

In the sealing part 9, the lead conductor 3 is adhere | attached (heat-sealed) with the sealing container (laminate film 8) through the 1st insulating layer 4b and the 2nd insulating layer 4a. Inside the nonaqueous electrolyte battery, a positive electrode current collector 10 and a negative electrode current collector 11, a nonaqueous electrolyte 13, and a separator 12 connected to the ends of the lead conductor 3 are further enclosed.

3 is a schematic cross-sectional view of a lead wire. The 1st insulating layer 4b is coat | covered on the surface of the plate-shaped lead conductor 3, and the 2nd insulating layer 4a coat | covers the outer side further. You may provide an insulating layer further outside the 2nd insulating layer 4a. The insulating layer 4a and the insulating layer 4b are melted by the heat | fever at the time of heat sealing, and adhere | attach a sealing container and a lead conductor. On the other hand, a lead wire may be called a tab lead.

Resin which can be melted by the heat | fever at the time of heat-sealing, and adhesiveness with respect to a metal (lead conductor) and an olefin resin (2nd insulating layer 4a) can be used for the 1st insulating layer 4b. Polyethylene, polypropylene, ethylene-based elastomers, styrene-based elastomers, ionomer resins and the like can be used as resins having good adhesion to olefin-based resins. Moreover, if these resins are acid-modified, adhesiveness with a metal will improve and it is preferable. For example, maleic acid, acrylic acid, methacrylic acid, maleic anhydride, polyethylene, polypropylene, ethylene-based elastomers, propylene-based elastomers, styrene-based elastomers, ionomer resins and the like modified with epoxy groups may be used. Maleic acid modified polyolefins may be preferably used.

The 2nd insulating layer 4a uses the olefin crystal ethylene octene olefin crystal block polymer, and the crosslinked body of the resin composition containing polypropylene in mass ratio 10: 90-40: 60. The olefin crystal, ethylene octene, and olefin crystal block polymers are excellent in compatibility with polypropylene and also excellent in crosslinkability. For this reason, the resin composition which comprises the 2nd insulating layer 4a becomes crosslinkable, even if it reduces the quantity of crosslinking adjuvant, and can manufacture it without adversely affecting the molding equipment or a product at the time of processing a resin composition into a sheet form. Can be. As the olefin crystal portion, a crystalline polyethylene copolymer is preferably used. As the polypropylene, random polypropylene, block polypropylene, acid-modified polypropylene, epoxy-modified propylene and the like can be used.

The 2nd insulating layer 4a is bridge | crosslinked and used by irradiation of ionizing radiation, such as an accelerating electron beam and a gamma ray. By bridge | crosslinking, heat resistance can be improved and the fall of the adhesive force at the time of the temperature at the time of use, and the short circuit of a lead conductor and a metal layer can be prevented.

As for the mass ratio of an olefin crystal ethylene octene olefin crystal block polymer (CEOC), and a polypropylene, 10: 90-40: 60 are preferable. If the amount of polypropylene is larger than this range, the crosslinking property is deteriorated, and there is a possibility that the lead wire and the metal layer are short-circuited due to melting during thermal fusion. In addition, when the amount of polypropylene is smaller than this range, the amount of flexible and tackily CEOC is relatively increased, whereby the insulating layer 4a may adsorb particles such as dust.

As for the difference of melting | fusing point of an olefin crystal ethylene octene olefin crystal block polymer (CEOC) and a polypropylene, 50 degrees C or less is preferable. More preferably, it is 40 degrees C or less, More preferably, it is 25 degrees C or less. If the difference in melting point is small, the film formability will improve by improving compatibility of resins. Moreover, since olefin crystal ethylene octene olefin crystal block polymer (CEOC) with high melting | fusing point is easy to crosslink compared with low melting | fusing point, the heat resistance of an insulating layer can be improved.

You may mix a crosslinking adjuvant with the resin composition which comprises the 2nd insulating layer 4a in the range which does not impair the meaning of this indication. A crosslinking adjuvant consists of a compound containing at least 2 or more unsaturated groups in a molecule | numerator. Examples of the crosslinking aid include triallyl isocyanurate (TAIC®), trimethylolpropane trimethacrylate, tris (2-acryloyloxyethyl) isocyanurate, and the like. 4 mass parts or less are preferable with respect to 100 mass parts of resin components, and, as for the quantity of a crosslinking adjuvant, 2 mass parts or less are more preferable.

In addition to these resins, various additives, such as a flame retardant, a ultraviolet absorber, a light stabilizer, a heat stabilizer, a lubricating agent, and a coloring agent, can be mixed with a 1st insulating layer and a 2nd insulating layer. These resin materials and additives are mixed using known mixing apparatuses such as open rolls, pressurized kneaders, single screw mixers, and twin screw mixers, and then a film-like insulating layer is produced by extrusion molding or the like. Although the thickness of a 1st insulating layer and a 2nd insulating layer depends on the thickness of a lead conductor, 30 micrometers-200 micrometers are preferable in total.

As the lead conductor 3, metals, such as aluminum, an aluminum alloy, nickel, a nickel alloy, copper, a copper alloy, nickel plating copper, are used. In the case of a lithium ion battery, aluminum is often used for a positive electrode and nickel or nickel plating copper is used for a negative electrode. The shape of the lead conductor is not particularly limited, but a flat metal having a thickness of 50 μm to 2 mm, a width of 1 mm to 200 mm, and a length of 5 mm to 200 mm can be preferably used.

Example

Next, the present disclosure will be described in more detail based on examples. The examples do not limit the scope of the invention.

Experimental Examples 1 to 18

[Production of Resin Composition for Insulating Layer Formation]

The compound used for adjustment of the resin composition for insulating layer formation is shown below.

(Resin ingredient)

Random PP (PP: Polypropylene): Novatec® FX4G (melting point 130 ° C, MFR 5g / 10min)

Acid Denatured Random PP Mixture: Admer® QF551 (Melting Point 135 ° C, MFR 6g / 10min)

Olefin crystal, ethylene butene, olefin crystal block polymer (CEBC) (melting point 95 degrees Celsius)

Olefin crystal, ethylene octene, olefin crystal block polymer (CEOC) 1 (melting point 122 degrees Celsius)

Olefin crystal, ethylene octene, olefin crystal block polymer (CEOC) 2 (melting point 118 degrees Celsius)

Ethylene Butene Copolymer 1: Tarpmer® DF640 (Melting Point 55 ° C, MFR 6g / 10min)

Ethylene octene copolymer 2: Tarpmer (registered trademark) DF610 (melting point 55 ° C., MFR 3 g / 10 min)

Ethylene Propylene Copolymer: Tarpmer® P280 (Melting Point 55 ° C, MFR 5g / 10min)

Ethylene octene copolymer: Engage® 8150 (melting point 55 ° C., MFR 1 g / 10 min)

(Cross-linking preparation)

Crosslinking Preparation 1: Triallyl Isocyanurate

Crosslinking Preparation 2: Trimethylolpropane Trimethacrylate

(Antioxidant)

Antioxidant 1: Ilganox® 1076

[Formation of Insulation Layer and Evaluation of Film Formability]

Using the said material, each material was mixed by the compounding shown in Table 1 and Table 2, and the resin composition for insulating layer formation was obtained. The obtained resin composition was shape | molded in the sheet form using the T-die method. Using the nip roll system, the die thickness of the T die was set to 0.05 mm and the air gap between the die-cooling rolls to 50 mm to form an insulating layer having a thickness of 0.05 mm. The film-forming speed was raised gradually and the film-forming speed which can produce a sheet favorably was measured. The film-forming speed | rate was 20 m / min or more as the pass value. On the other hand, the room temperature at the time of film-forming was 10 degreeC, and the vapor generation amount of the crosslinking adjuvant at the time of film-forming was visually observed.

[crosslinking by irradiation of gamma rays]

120 kGy (gamma) rays were irradiated and bridge | crosslinked the obtained insulating layer.

[Bleed out attribute (time period until bleed reaches certain amount)]

The crosslinked insulating layer sheet was cut out to a regular size and stored at room temperature for a certain period. The amount of crosslinking aid bleeded out on the surface of this sheet was quantified by ATR-IR (Attenuated Total Reflectance-Infrared Spectroscopy). Specifically, in the peak (1700 cm ^-1 ) characteristic of the crosslinking aid, the peak height (A%) when the film is measured as it is and the peak height (B%) when the film surface is measured after wiping off the film surface with ethanol It measured and calculated | required the period until AB became 4%. Passed more than four weeks. About the experiment example which does not contain a crosslinking adjuvant, it displayed with "None" in the table.

[Evaluation of Heat Strain Residuals]

The heat deformation residual ratio of the crosslinked insulating layer sheet was evaluated. Specifically, the sheet sample was placed in a TMA (Thermal Mechanical Analysis) apparatus, and the temperature was raised while a load of 0.1 MPa was applied to the probe, and the thickness at room temperature and the thickness at 200 ° C. were measured. The ratio of thickness in 200 degreeC with respect to thickness in room temperature was made into the heat distortion residual rate (%). 40% or more were made into the pass. The above results are shown in Table 1 and Table 2.

Experimental examples 1-8 are the sheet | seat which mixed olefin crystal ethylene octene olefin crystal block polymer (CEOC) with polypropylene resin or acid-modified polypropylene resin, and bridge | crosslinked by (gamma) ray irradiation. Although Experimental Examples 1-5 and Experimental Example 7, 8 did not add a crosslinking adjuvant, the heat deformation residual ratio which is an index of crosslinkability is 40% or more, and it turns out that it crosslinks favorably. In addition, although 1 part of crosslinking adjuvant was mixed with respect to 100 mass parts of resin components in Experimental example 6, generation | occurrence | production of the crosslinking adjuvant at the time of film-forming is few, and the bleed out characteristic of a crosslinking adjuvant exceeds four weeks which are a pass value. In addition, any sheet can be formed at a speed of 20 m / min or more, so that the productivity is also good.

In Experimental Example 9, an olefin crystal ethylene butene olefin crystal block polymer (CEBC) is used instead of the olefin crystal ethylene octene olefin crystal block polymer (CEOC). Although the generation | occurrence | production of the crosslinking adjuvant vapor | vapor at the time of film-forming is small, and the bleed out characteristic of a crosslinking adjuvant is also passed, the upper limit of the film-forming speed | rate is 15 m / min, and it is inferior to film forming properties compared with Experimental Examples 1-8. It is thought that this is because the melting point of CEBC is low at 95 ° C and the difference with the melting point (130 ° C) of the polypropylene resin is large. Moreover, compared with the experiment example 2 with the same mixture ratio, the heat distortion residual rate which is an index of crosslinkability is low. From this, it is estimated that CEOC is easy to bridge | crosslink compared with CEBC.

Experimental example 10-12 is a sheet | seat which mixed and bridge | crosslinked the crosslinking adjuvant to polypropylene resin or acid-modified polypropylene resin, without using an olefin crystal ethylene octene olefin crystal block polymer (CEBC). Although the heat deformation residual ratio is a good result at 95%, generation | occurrence | production of the crosslinking adjuvant steam at the time of shaping | molding is large, and bleeding out of a crosslinking adjuvant is also increasing.

Experimental Example 13 uses a single polypropylene resin. Compared with others, the heat distortion residual rate is low and it is guessed that a crosslinking reaction does not fully occur. Experimental example 14 mixes 1 part of crosslinking adjuvant with respect to 100 mass parts of polypropylene resins. Although generation | occurrence | production of a crosslinking preparation vapor | steam is few and heat distortion residual is also favorable, the upper limit of the film-forming speed | rate is slightly slowing down to 15 m / min.

Experimental examples 15-18 are sheets which mixed resin other than olefin crystal ethylene butene olefin crystal block polymer (CEBC), and polypropylene resin, and bridge | crosslinked by (gamma) ray irradiation. It is speculated that the crosslinking reaction has occurred because the heat deformation residual ratio exceeds the pass value, but the film formation rate is low, resulting in poor workability.

The disclosed embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the present invention is not limited to the configuration of the above embodiment, but is indicated by the claims, and is intended to include all modifications within the meaning and range equivalent to the claims.

1: nonaqueous electrolyte battery
2: encapsulation container
3: lead conductor
4a: second insulating layer
4b: first insulating layer
5: metal layer
6: resin layer
7: resin layer
8: laminate film
9: sealing part
10: anode current collector
11: cathode current collector
12: separator
13: nonaqueous electrolyte

Claims (8)

A lead wire for a nonaqueous electrolyte battery having a lead conductor, a first insulating layer directly covering at least a portion of the lead conductor, and a second insulating layer covering the first insulating layer,
The said 2nd insulating layer is a lead wire for nonaqueous electrolyte batteries which is a crosslinked body of an olefin crystal ethylene octene olefin crystal block polymer, and the resin composition which contains a polypropylene by mass ratio 10: 90-40: 60. The method of claim 1,
The lead wire for nonaqueous electrolyte batteries whose difference of melting | fusing point of the said olefin crystalline ethylene octene olefin crystal block polymer and melting | fusing point of the said polypropylene is 50 degrees C or less. The method according to claim 1 or 2,
A lead wire for nonaqueous electrolyte batteries, wherein the first insulating layer contains an acid-modified polyolefin. The method according to any one of claims 1 to 3,
The polypropylene is a random polypropylene or acid-modified polypropylene, a lead wire for a nonaqueous electrolyte battery. The method according to any one of claims 1 to 4,
The thickness of the sum total of a said 1st insulating layer and a said 2nd insulating layer is 30 micrometers or more and 200 micrometers or less, The lead wire for nonaqueous electrolyte batteries. The method of claim 3, wherein
The acid-modified polyolefin is a maleic anhydride-modified polyolefin. The method of claim 1,
The first insulating layer comprises maleic anhydride-modified polyolefin,
The polypropylene is a random polypropylene or acid-modified polypropylene, a lead wire for a nonaqueous electrolyte battery. The nonaqueous electrolyte battery provided with the lead wire for nonaqueous electrolyte batteries in any one of Claims 1-7.

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