KR20120023538A - Laminate for cell exterior - Google Patents

Abstract

PURPOSE: A laminate for battery exterior is provided to reduce the generation of delamination between layers, and the decrease of laminating strength of an inner-most layer and an aluminum foil due to deterioration of electrolyte of a lithium ion secondary battery. CONSTITUTION: A laminate for battery exterior(10) comprises a base material layer(11), an aluminum foil, and an inner-most layer consisting of a polypropylene or polyethylene layer laminated in order. A thin film coating layer, which consists of a resin having polyvinylalcohol structure containing hydroxyl group or a copolymer thereof, is laminated on a side of at least the inner-most layer of the aluminum foil. The tensile fracture elongation of the laminate measured by the method ruled in JIS K7127, is 50% or more at any direction of MD directions and TD directions.

Description

Battery exterior laminated body {LAMINATE FOR CELL EXTERIOR}

TECHNICAL FIELD This invention relates to the battery exterior laminated body used for the exterior material of secondary batteries, such as a lithium ion battery, and an electric double layer capacitor (henceforth "capacitor").

This application claims priority based on Japanese Patent Application No. 2010-172265 for which it applied to Japan on July 30, 2010, and uses the content here.

In recent years, with the rise of global environmental problems, the use of natural energy, such as the spread of electric vehicles and wind power and solar power generation, has become a problem. Accordingly, in these technical fields, attention has been paid to secondary batteries such as lithium ion batteries and capacitors as storage batteries for storing electrical energy. Moreover, in the outer container which accommodates lithium ion batteries used for an electric vehicle etc., the envelope-type container manufactured using the battery exterior laminated body which laminated | stacked aluminum foil and the resin film, drawing-molding or unloading, The molding container by shaping | molding is used, and thin weight reduction is aimed at.

By the way, the electrolyte of a lithium ion battery has the property which is weak to moisture and light. Therefore, the base material layer (resin film) which consists of polyamide and polyester, and aluminum foil are laminated | stacked on the lithium ion battery exterior material, and the battery exterior laminated body (aluminum laminating film) excellent in waterproofness, light-shielding properties, etc. It is used.

In order to store a lithium ion battery in the storage container manufactured using such a battery exterior laminated body, for example, as shown in FIG.3 (A), the recessed part (using a battery exterior laminated body is used previously). A tray-shaped mounting container 30 having a 31 is molded by drawing molding or the like, and a lithium ion battery (not shown) and an electrode (not shown) are formed in the recess 31 of the tray (mounting container 30). 36) Accessories (refer FIG. 3 (B)) are stored. Subsequently, as shown in FIG. 3 (B), the battery is wrapped by overlapping the cover material 33 made of the battery packaging laminate from above, and the sides of the tray flange 32 and the cover material 33 are surrounded on all sides. The part 34 is heat sealed to seal the battery. In the storage container 35 manufactured by the method of mounting a battery in the recessed part 31 of such a tray, since a battery can be accommodated from the top, productivity is high.

In the container 30 for mounting the lithium ion battery shown in FIG. 3A, the depth of the tray (hereinafter, the depth of the tray may be referred to as "drawing") is conventionally used for a small lithium ion battery. It was about 5-6 mm. By the way, in recent years, the use of large battery storage containers is calculated | required larger than ever before in the use of electric vehicles. In order to manufacture a large-sized battery storage container, the tray of deeper drawing must be shape | molded, and the technical difficulty is increasing.

Moreover, when moisture invades the inside of a lithium ion battery, electrolyte solution and moisture will react, an electrolyte solution will decompose | disassemble, and strong acid (hydrofluoric acid etc.) will generate | occur | produce. In this case, the generated strong acid penetrates into the battery packaging laminate from the inside thereof, and the aluminum foil may corrode with the strong acid and deteriorate. As a result, liquid leakage of electrolyte occurs, and not only battery performance falls but also a lithium ion battery may ignite.

As a countermeasure against the corrosion of the aluminum foil constituting the battery exterior laminate with a strong acid, Japanese Patent Application Laid-open No. 2000-357494 discloses a chromium treatment coating by performing chromate treatment on the surface of an aluminum foil. The countermeasure which forms and improves corrosion resistance is disclosed.

Japanese Patent Application Publication No. 2000-357494

However, since chromate treatment uses chromium which is a heavy metal, it is not preferable in view of environmental measures. In addition, in the chemical conversion treatment other than the chromate treatment, the effect of improving the corrosion resistance is low.

In addition, when a conventional aluminum laminating film is molded or bent by deep drawing and overlaps, corner portions or bent portions may be stretched, and the stretching may eventually reach a limit, and may break, causing pinholes or tearing. . Moreover, there exists a possibility that the adhesive surface of an aluminum foil and a base material layer may yield and peel by the stress at the time of increase. Since such defects at the time of molding occur, the production efficiency of a storage container such as a lithium ion battery is lowered.

This invention is made | formed in view of the above-mentioned situation, and can reduce the fall of lamination | strength strength of an aluminum foil and an innermost layer by the deterioration of the electrolyte solution of a lithium ion battery, and the occurrence of interlayer peeling, and An object of the present invention is to provide a laminate for battery packaging that can manufacture an outer container with a high yield.

According to the present invention, in the battery packaging laminate in which an aluminum foil and a resin layer are sequentially stacked, an innermost layer made of a base material layer, an aluminum foil, and a polypropylene or polyethylene layer is sequentially stacked, and the aluminum The thin film coating layer which consists of resin which has frame | skeleton of polyvinyl alcohol containing a hydroxyl group, or its copolymer resin is laminated | stacked at least on the surface of the innermost layer side among foils.

The thin film coating layer is made of a metal fluoride or a derivative thereof and crosslinks a resin having a skeleton of a polyvinyl alcohol containing a hydroxyl group contained in the thin film coating layer or a copolymer resin thereof, and further floats the surface of the aluminum foil. It is preferred that a passivation material is included.

Moreover, it is preferable that it is measured by the measuring method prescribed | regulated to JISK7127, and it is preferable that the tensile breaking elongation of the said laminated body is 50% or more in any direction of MD direction and TD direction.

Moreover, it is preferable that the said thin film coating layer is crosslinked or amorphous, and has been water-resistant by heat processing. That is, it is preferable that it is the structure which suppressed the ingress of water from the cross section of the battery exterior laminated body.

Moreover, it is preferable that the said base material layer and the said aluminum foil adhere | attach through a urethane type adhesive agent, and the said aluminum foil and the said innermost layer are adhere | attached via any one of a urethane type adhesive agent, an acid-modified polyolefin resin, and an epoxy-group containing polyolefin resin.

Moreover, the thickness of the said innermost layer is 20 micrometers or more and 50 micrometers or less, and the adhesive strength of the said aluminum foil and the innermost layer is based on the measuring method prescribed | regulated by the peeling measuring method A prescribed | regulated to JIS C6471. It is preferable that it is 20 N / inch or more by measuring. This is because the pressure resistance strength of the heat sealing portion is maintained, while the thinner the cross-section sealant is, the more water is submerged.

According to this invention, since the thin film coating layer is laminated | stacked on at least one surface (surface used as innermost layer side) of an aluminum foil, the adhesive strength of an aluminum foil and an innermost layer becomes very high. Therefore, when a tray is shape | molded by drawing shaping | molding or elongation shaping | molding using the battery exterior laminated body, generation | occurrence | production of a pinhole can be prevented and peeling of a base material layer and aluminum foil can be prevented. Therefore, the occurrence of defects in molding the storage container is reduced.

In addition, since the breakdown strength of the battery packaging laminate is high for the same reason, the breakdown strength can be maintained even if the thickness of the innermost layer of the polypropylene layer or the polyethylene layer is reduced. Therefore, the immersion of water from the edge portion (side circumference) of the storage container into the lithium ion battery becomes less, and the deterioration of the electrolyte solution of the lithium ion battery with time decreases, resulting in a longer product life of the battery.

BRIEF DESCRIPTION OF THE DRAWINGS It is a perspective view of the storage container for batteries manufactured using the battery exterior laminated body in embodiment of this invention.
2 is a schematic cross-sectional view of a battery exterior laminate in an embodiment of the present invention.
3A is a perspective view showing a first step of accommodating a lithium ion battery in a storage container.
FIG. 3B is a perspective view illustrating a second step of storing a lithium ion battery in a storage container.
4 is a measurement result of measuring the thermal change of the thin film coating layer by the differential thermal analysis device.

The battery exterior laminate according to the present invention will be described with reference to FIGS. 1 to 4. And it demonstrates taking the storage container for lithium ion batteries manufactured using the battery exterior laminated body as an example.

As shown in FIG. 1, the battery packaging container 20 manufactured using the battery packaging laminate of the present invention is bent and overlapped with the battery packaging laminate 10 to overlap the lithium ion battery 17 and the electrode 18. Is encapsulated and heat-sealed in three directions of the side circumferential portions 19 of the battery packaging container 20 to produce an envelope. In addition, the storage method of the lithium ion battery in the battery storage container manufactured using the battery exterior laminated body which concerns on this invention was referred to FIG. 3A and FIG. 3B, and is the same as the method mentioned above. .

As shown in FIG. 2, the battery packaging laminate 10 is bonded to the base material layer 11, the aluminum foil 12, and the innermost layer 13 through the adhesive layers 15 and 16, respectively. .

Moreover, the thin film coating layer 14 which consists of resin which has a skeleton of polyvinyl alcohol containing a hydroxyl group, or its copolymer resin is laminated | stacked on at least one surface (surface used as the innermost layer 13 side) of the aluminum foil 12, have.

Further, the thin film coating layer 14 is made of a metal fluoride or a derivative thereof, and crosslinks a resin having a skeleton of a polyvinyl alcohol containing a hydroxyl group contained in the thin film coating layer 14 or a copolymer resin thereof, and further contains an aluminum foil ( It contains a material that passivates the surface of 12).

In addition, this battery exterior laminated body 10 is measured by the measuring method prescribed | regulated to JISK7127, and tensile breaking elongation of the battery exterior laminated body 10 is MD direction (flow direction) and TD direction (vertical direction). It is 50% or more in either direction.

Tensile breaking elongation is the tensile breaking elongation calculated | required based on JISK7127 and measured by 50 mm / min of tensile velocity. If the tensile elongation at break of the battery packaging laminate 10 is 50% or more in any of the MD and TD directions, even when the battery packaging laminate 10 is bent and overlapped or molded by deep drawing, the corner portion ( The bent portion) stretches sufficiently and does not break, so no pinhole occurs.

In addition, the base material layer 11 and the aluminum foil 12 are bonded through a urethane adhesive, and the innermost layer 13 made of the aluminum foil 12 and polypropylene or polyethylene is bonded through a urethane adhesive or an acid-modified polyolefin. It is.

In addition, the adhesive strength of the aluminum foil 12 and the innermost layer 13 which consists of a polypropylene or polyethylene layer is measured by the measuring method prescribed | regulated to JIS C6471, and is 20 N / inch or more.

The base material layer 11 is not particularly limited as long as it has a high mechanical strength, and for example, a laminated structural material of a biaxially stretched nylon film (ONy), a polyethylene terephthalate (PET) film, and a PET / polyamide (nylon) film Etc. are used. It is preferable that it is 12-60 micrometers, and, as for the thickness of the base material layer 11, it is more preferable that it is 25-50 micrometers. If the thickness of the base material layer 11 is 12-60 micrometers, the balance of elasticity modulus and strength is excellent.

The aluminum foil 12 is used to provide waterproofness and light blocking property to a battery outer container and is an insulating layer for insulating from the outside. The aluminum foil 12 used is not particularly limited. On the inner surface of the battery foil (lithium ion battery 17) side of the aluminum foil 12, a thin film coating layer 14 made of a resin having a skeleton of polyvinyl alcohol containing a hydroxyl group or a copolymer resin thereof is laminated.

Resin which has a skeleton of polyvinyl alcohol containing a hydroxyl group, or its copolymerization resin is resin obtained by saponifying the polymer of a vinyl ester monomer or its copolymer.

Examples of the vinyl ester monomers include fatty acid vinyl esters such as vinyl formate, vinyl acetate and vinyl butyrate, and aromatic vinyl esters such as vinyl benzoate. Examples of the monomer to be copolymerized include unsaturated acids such as ethylene, propylene, α-olefins, acrylic acid, methacrylic acid and maleic anhydride, and vinyl halides such as vinyl chloride and vinylidene chloride. As a commercial item, G polymer resin (brand name) which is a product of Nippon Synthetic Chemical Co., Ltd. is mentioned.

Further, the thin film coating layer 14 is made of a metal fluoride or a derivative thereof, and crosslinks a resin having a skeleton of a polyvinyl alcohol containing a hydroxyl group contained in the thin film coating layer 14 or a copolymer resin thereof, and further contains an aluminum foil ( It is preferable to contain a substance which passivates the surface of 12). The metal fluoride or a derivative thereof is a substance containing F ^- ions which form a fluoride of passivated aluminum, and for example, chromium fluoride, iron fluoride, zirconium fluoride, titanium fluoride, hafnium fluoride, zircon hydrofluoric acid and salts thereof Fluorides such as titanium hydrofluoric acid and salts thereof.

In order to form the thin film coating layer 14 on the surface of the innermost layer 13 side of this aluminum foil 12, for example, an amorphous polymer having a skeleton of polyvinyl alcohol having a hydroxyl group [Japan Synthetic Chemical Co., Ltd.] Product, brand name: G polymer resin] and an aqueous solution in which 0.2 to 6 wt% of chromium (III) fluoride was dissolved by 0.1 to 3 wt% were applied so that the thickness after drying was about 0.1 to 5 mu m, and then The thin film coating layer 14 can be formed by performing heat drying.

At this time, when heat-processing to 180 degreeC or more which is the melting | fusing point of resin which has a skeleton of polyvinyl alcohol which has a hydroxyl group, or its copolymerization resin, a polymer will crosslink and water resistance improves. This is determined by whether the crosslinking is performed by measuring the melting point of the thin film coating layer before and after the heat treatment at a temperature higher than the melting point by a differential thermal analysis device, but the thin film coating layer heat treated at a temperature higher than the melting point has a peak of melting point. Since there is no, it can be seen that it is crosslinked. Moreover, even if it was immersed in hot water, the change of this heat-treated thin film coating layer was not observed.

When the thin film coating layer 14 is laminated on at least one surface (surface which becomes the innermost layer 13 side) of the aluminum foil 12, since the pressure resistance strength of the battery exterior laminate is improved, the polypropylene which is the innermost layer 13 is Even if the thickness of the layer or polyethylene layer is made thin, the breakdown strength can be maintained. Therefore, water immersion from the edge portion (side circumferential portion) of the battery packaging container 20 to the inside of the lithium ion battery decreases, and the deterioration of the electrolyte solution of the lithium ion battery with time decreases, resulting in a long product life of the battery.

In addition, according to the present invention, since the thin film coating layer 14 is laminated on at least one surface (innermost layer 13 side surface) of the aluminum foil 12, adhesion between the aluminum foil 12 and the innermost layer 13 is achieved. The strength is very high. Therefore, when the tray is molded by drawing molding or elongate molding using the battery packaging laminate, pinholes are prevented from occurring and peeling of the base layer 11 and the aluminum foil 12 can be prevented. Therefore, the occurrence of defects in molding the storage container is reduced.

In addition, even when a small amount of water is immersed in the battery, the electrolyte and water react to decompose the electrolyte, and hydrofluoric acid is generated, it contains a hydroxyl group laminated on the surface of the innermost layer 13 side of the aluminum foil 12. The thin film coating layer 14 made of a resin having a polyvinyl alcohol skeleton or a copolymer resin thereof has a low free volume (empty pores and voids in the layer), and thus has a high gas barrier property and is also an innermost layer which is also a sealant layer. Along with (13), it is possible to prevent the hydrofluoric acid from diffusing to the outside. In addition, even when a trace amount of hydrofluoric acid contacts the surface of the aluminum foil 12, the corrosion of the aluminum foil 12 is prevented by the passivation film formed on the surface of the aluminum foil 12. Therefore, the interlayer adhesion strength between the aluminum foil 12 and the sealant layer is maintained and the breakdown voltage strength is kept high, so that battery performance is also not deteriorated.

The thickness of the aluminum foil 12 is 20-100 micrometers. When the thickness of the aluminum foil 12 is 30-60 micrometers, since sufficient waterproofness and light-shielding property are expressed and workability is also favorable, it is preferable. 0.2-10 micrometers is preferable and, as for the thickness of the thin film coating layer 14 which consists of resin which has a skeleton of polyvinyl alcohol containing a hydroxyl group, or its copolymerization resin, 0.5-3 micrometers is more preferable. If the thickness of the thin film coating layer 14 is 0.2-10 micrometers, the performance of moisture proof property or adhesive strength will increase.

The innermost layer 13 made of polypropylene or polyethylene is a layer mainly containing polypropylene or polyethylene, and becomes the innermost layer when the battery packaging container 20 is manufactured using the battery packaging laminate 10. And a layer in contact with the lithium ion battery 17. The reason why the innermost layer 13 made of polypropylene or polyethylene is in contact with the lithium ion battery 17 is that the polypropylene or polyethylene is excellent in corrosion resistance to the electrolyte solution of the lithium ion battery and good heat sealing property. Because. In addition, heat sealing property shows the stability (or the property which can be bonded or bonded by applying heat) of sealing in high temperature.

When the innermost layer 13 is polypropylene, the polypropylene used for the innermost layer 13 may be a propylene homopolymer or a copolymer with ethylene. The copolymer with ethylene may be a random copolymer or a block copolymer. When the innermost layer 13 is polyethylene, LLDPE is preferable as polyethylene used for the innermost layer 13, and may be a copolymer of HDPE, LDPE, maleic anhydride, acrylic acid, or the like.

It is preferable that the thickness of the innermost layer 13 which consists of polypropylene is 20-100 micrometers. In the case where the innermost layer 13 is made of polypropylene, the corrosion resistance and heat sealing resistance to the electrolyte solution and sufficient breakdown strength are achieved even if the innermost layer 13 is not excessively thick, such as having a thickness of 100 µm or more. Since it can keep constant, it is preferable. In particular, it is very preferable to use polypropylene as the material of the innermost layer 13, since the immersion of water from the heat-sealed point can be prevented and the deterioration of the non-aqueous battery and capacitor can be prevented.

The adhesive bond layer 15 is a layer which adheres the base material layer 11 and the aluminum foil 12. As an adhesive agent contained in the adhesive bond layer 15, if the base material layer 11 and the aluminum foil 12 can be adhere | attached, it will not specifically limit, For example, an epoxy adhesive, a urethane type adhesive, etc. are mentioned. When the adhesive bond layer 15 consists of an epoxy adhesive, a urethane adhesive, etc., normally, the adhesive bond layer 15 is laminated | stacked on the base material layer 11 or the aluminum foil 12 by dry laminating.

The thickness of the adhesive bond layer 15 is 3-10 micrometers. Since the thickness of the adhesive bond layer 15 is 3-10 micrometers, the base material layer 11 and the aluminum foil 12 can be bonded by a sufficiently high adhesive force. Therefore, even when the battery exterior laminate 10 is draw-molded or elongated-molded, adhesion at the bent portion and the deformed portion is maintained, and the base layer 11 and the aluminum foil 12 are not separated from each other.

An adhesive may or may not be used for adhesion between the thin film coating layer 14 of the aluminum foil 12 and the innermost layer 13 made of polypropylene or polyethylene. However, when an adhesive agent is used, since the electrolyte solution of a lithium ion battery may reduce the adhesive strength of an adhesive agent, it is preferable not to use an adhesive agent for adhesion of the aluminum foil 12 and the innermost layer 13.

When no adhesive is used, it is preferable to use a resin having a skeleton of polyvinyl alcohol containing a hydroxyl group or a copolymer resin thereof for bonding the thin film coating layer 14 of the aluminum foil 12 to the innermost layer 13. desirable. In this case, since heat adhesiveness with maleic anhydride modified polyolefin resin, an epoxy group containing polyolefin resin, etc. and innermost layer 13 is high, it is a heat | fever of moving maleic acid modified polyolefin resin and an epoxy group containing polyolefin resin by extrusion lamination or thermal laminating. Through the sealing agent, the thin film coating layer 14 and the innermost layer 13 of the aluminum foil 12 can be adhered.

Moreover, as an adhesive agent in the case of using an adhesive agent for bonding the thin film coating layer 14 and the innermost layer 13 of the aluminum foil 12, a urethane type adhesive agent, an epoxy type adhesive agent, an acid-modified polyolefin, etc. can be used, for example. Can be. As the acid-modified polyolefin, it is preferable to use maleic anhydride-modified polypropylene. The use of maleic anhydride-modified polypropylene is preferable because the adhesiveness and long-term adhesion performance are increased.

In the battery packaging container 20, the tensile breaking elongation of the battery packaging laminate 10 being used is 50% or more, and the thickness of the aluminum foil 12 of the battery packaging laminate 10 and the adhesive layer 15 are shown. , 16) is optimized. Therefore, when the tray for forming the battery exterior laminate 10 is formed by drawing molding or elongation molding, the corner portion and the bent portion are sufficiently stretched, so that no break occurs, and no pinhole occurs. Moreover, since the adhesive force between the base material layer 11 and the aluminum foil 12 is sufficiently high, and does not yield to the stress at the time of extension, peeling can be prevented.

[Example]

(How to measure)

Measurement method of tensile fracture elongation of laminated body: It measured by the measuring method prescribed | regulated to JISK7127 "Test method of plastic-tensile property-Part 3: Test conditions of film and sheet."

-Measuring method of adhesive strength between aluminum foil and innermost layer: It measured by the peeling measuring method A (90 degreeC direction peeling) prescribed | regulated to JIS C6471 "The copper clad laminated board test method for flexible printed wiring boards."

Measuring method of pinhole breakage incidence: 50 drawing molded articles by cold forming at a predetermined depth within a range of 6 to 10 mm in a size of 50 × 50 mm, and pinholes are measured by visual observation. It was.

? Electrolyte measurement method of strength retention rate: Using the prepared cell exterior laminate, 50 × 50 mm and made of 4-room bags (bags of the rectangle of the heat-seal width of 5mm), 1mol of LiPF ₆ in his / A solution in which 0.5 wt% of pure water was added to the propylene carbonate (PC) / diethyl carbonate (DEC) electrolyte solution added was weighed at 2 cc, filled and packed. After storing this four bag in a 60 degreeC oven for 100 hours, the interlayer adhesive strength (k2) of aluminum foil and a polypropylene (PP) film (innermost layer) was measured.

And the ratio of the interlayer adhesive strength (k1) of the aluminum foil and polypropylene (PP) film before exposure to electrolyte solution measured beforehand, and the interlayer adhesive strength (k2) after exposing to electrolyte solution is electrolyte solution. Strength retention ratio K = (k2 / k1) x100 (%) was taken.

(Measuring device)

Tensile breaking elongation measuring device: Manufacturer name: Shimadzu Corporation, Model: AUTOGRAPH AGS-100A Tensile test device

Adhesion strength measuring device: Manufacturer name: Shimadzu Corporation, Model: AUTOGRAPH AGS-100A Tensile test device

(Example 1)

A 25-micrometer-thick base material layer made of polyamide (nylon) resin and an aluminum foil having a thickness of 40 μm were laminated with an adhesive layer made of a urethane-based adhesive (containing an epoxy clock adhesive) 7 μm therebetween.

3 wt% of an amorphous polymer having a skeleton of a polyvinyl alcohol having a hydroxyl group on the surface of the innermost layer side of this aluminum foil (made by Nippon Synthetic Chemical Co., Ltd., trade name: G polymer resin), and 1 wt% of chromium (III) fluoride The aqueous solution which melt | dissolved% was apply | coated to the thickness of 1 micrometer, the thin film coating layer was laminated | stacked, and the heat drying process was performed by the oven of 200 degreeC.

Further, an acid-modified polypropylene heat sealing agent was applied at 3 g / m ² on the thin film coating layer of aluminum foil, and a polypropylene layer 30 μm was laminated thereon to laminate the battery exterior laminate 10 of Example 1 Prepared.

The test piece for measuring the tensile elongation at break was taken from the battery packaging laminate 10 of Example 1, and the tensile elongation at break in the MD direction and the TD direction was measured. In addition, in the battery exterior laminate 10 of this Example 1, drawing molding was performed 50 times in a depth of 6 mm and 8 mm, the number of pinhole breaks was measured, and the pinhole breakage incidence rate was determined. Moreover, the test piece for adhesive strength measurement of an aluminum foil and an innermost layer was extract | collected from the battery exterior laminated body 10 of this Example 1, and the adhesive strength of an aluminum foil and an innermost layer was measured. These measurement results are shown in Table 1.

Moreover, it was K = 85% when the electrolyte solution strength retention ratio K was measured about the battery exterior laminated body of Example 1.

(Example 2)

3 wt% of an amorphous polymer [product made by Nippon Synthetic Chemical Co., Ltd., brand name: G polymer resin] having a skeleton of polyvinyl alcohol having a hydroxyl group on the surface of the innermost layer side of the aluminum foil, and 1 wt% of chromium (III) fluoride The melted aqueous solution was apply | coated to the thickness of 3 micrometers, the thin film coating layer was laminated | stacked, and the heat drying process was performed by the oven of 200 degreeC.

The heat change of the thin film coating layer subjected to this heat treatment was measured by a differential thermal analysis device, and the melting point of the thin film coating layer was confirmed. As a result, there was no peak of melting point, indicating that the resin was crosslinked. The result of having measured the thin film coating layer by the differential thermal analysis apparatus in FIG. 4 is shown. And as shown in FIG. 4, as a comparison object, the heat change of the thin film coating layer which did not heat-process by oven was measured similarly.

Further, an acid-modified polypropylene heat sealing agent was applied at 3 g / m ² on a thin film coating layer of aluminum foil, and a 30 μm polypropylene layer was laminated thereon to laminate the battery exterior laminate 10 of Example 2. About the obtained battery exterior laminated body 10 of Example 2, the measurement of tensile breaking elongation, the measurement of a pinhole break occurrence rate, and the adhesive strength of aluminum foil and an innermost layer were performed. These measurement results are shown in Table 1. Moreover, the result of having measured electrolyte solution strength maintenance ratio K with respect to the battery exterior laminated body of Example 2 was K = 78%.

(Comparative Example 1)

Except not having laminated | stacked the thin film coating layer on the aluminum foil, it carried out similarly to Example 1, and obtained the battery exterior laminated body 10 of the comparative example 1, the measurement of tensile breaking elongation, the measurement of a pinhole break occurrence rate, and aluminum foil And the adhesive strength with the innermost layer were measured. These measurement results are shown in Table 1.

Moreover, the result of having measured electrolyte solution strength maintenance ratio K with respect to the battery exterior laminated body of the comparative example 1 was K = 10% or less, and the aluminum foil and the innermost layer produced the peeling phenomenon (delaminating).

(Comparative Example 2)

3 wt% of an amorphous polymer having a skeleton of polyvinyl alcohol having a hydroxyl group on the surface of the innermost layer side of the aluminum foil (product of Nippon Synthetic Chemical Co., Ltd., trade name: G polymer resin), and 1 wt% of chromium (III) fluoride The mixed coating material was applied in a thickness of 1 μm, the thin film coating layer was laminated, and then the same as in Example 1 except that the heat-drying treatment was not performed. ) For the battery packaging laminate 10 of Comparative Example 2, the tensile elongation at break was measured, the pinhole break incidence rate was measured, and the adhesive strength between the aluminum foil and the innermost layer was measured. These measurement results are shown in Table 1.

[Table 1]

Examples 1 and 2 were mixed with 3 wt% of an amorphous polymer having a skeleton of polyvinyl alcohol having a hydroxyl group (manufactured by Nippon Synthetic Chemical Co., Ltd., trade name: G polymer resin), and 1 wt% of chromium fluoride (III). Since one paint is applied to the surface of the innermost layer side of the aluminum foil and the thin film coating layer is laminated, the adhesive strength between the aluminum foil and the innermost layer is 20 N / inch or more, and the tensile elongation at break is increased in both the MD direction and the TD direction. It exceeds 50%. Therefore, the incidence of pinhole breakage was low, resistant to electrolytes of lithium batteries, and high withstand pressure strength.

On the other hand, in Comparative Example 1, the adhesive strength between the aluminum foil and the innermost layer was 20 N / inch or more, the tensile breaking elongation was high, and no pinhole fracture occurred, but there was no electrolyte resistance and peeling phenomenon (delaminating) was observed. Looks like

Moreover, in the comparative example 2, since the adhesive strength of an aluminum foil and an innermost layer is less than 20 N / inch, tensile elongation at break is low, electrolyte solution tolerance is low, and pinhole fracture also generate | occur | produced.

(Example 3)

Epoxy-based base material layer and aluminum foil formed by laminating a polyethylene terephthalate (PET) film having a thickness of 5 µm and a polyamide (nylon) film layer having a thickness of 25 µm through a urethane-based adhesive layer coated at 3 g / m ² The urethane-based adhesive layer containing the adhesive was adhered with a thickness of 7 μm. Next, 3 wt% of an amorphous polymer having a skeleton of polyvinyl alcohol having a hydroxyl group on the surface opposite to the base layer of aluminum foil (manufactured by Nippon Synthetic Chemical Co., Ltd., trade name: G polymer resin), and chromium (III) fluoride (III) Was applied to an aqueous solution of 1wt% dissolved in a thickness of 3㎛, heat-treated at a temperature of 200 ℃ to form a thin film coating layer, and an acid-modified polypropylene heat sealing agent was applied at 3g / m ² thereafter, 40 micrometers of polypropylene layers were thermally laminated, and the battery exterior laminated body of Example 3 of a four-layered constitution was manufactured.

The test piece for measuring the tensile breaking elongation was taken from the battery-clad laminate of Example 3, and the tensile breaking elongation in the MD direction and the TD direction was measured. In addition, in the battery packaging laminate of Example 3, 8 mm and 10 mm depth drawing moldings were performed 50 times, and the number of pinhole breaks was measured to determine the pinhole breakage occurrence rate. In addition, the electrolyte solution strength maintenance ratio was measured. These measurement results are shown in Table 2.

(Example 4)

Except having made the thickness of the innermost polypropylene layer into 30 micrometers, it carried out similarly to Example 3, and obtained the battery exterior laminated body of Example 4, the measurement of tensile elongation at break, the measurement of pinhole break occurrence rate, and electrolyte solution The strength retention ratio was measured. These measurement results are shown in Table 2.

(Comparative Example 3)

After carrying out similarly to Example 3 except having formed the thin film coating layer using the coating liquid which does not add the chromium fluoride which is the substance which gives the passivation performance of aluminum, after obtaining the battery exterior laminated body of the comparative example 3, , The tensile elongation at break was measured, the pinhole break incidence was measured, and the electrolyte strength retention ratio was measured. These measurement results are shown in Table 2.

TABLE 2

Since Example 3 and Example 4 have high adhesive strength of aluminum foil and a sealant (innermost layer), tensile elongation at break is high. Moreover, since the value of the electrolyte solution strength maintenance ratio was high, it was excellent in electrolyte resistance, and also the pressure-resistant strength was enough, and the pinhole break occurrence rate was low.

On the other hand, in the comparative example 3, since the thin film coating layer was formed using the coating liquid which does not add the chromium fluoride which is the substance which gives the passivation performance of aluminum, the value of electrolyte strength retention ratio was low and the electrolyte resistance performance was not enough. .

Claims (6)

In a battery packaging laminate formed by sequentially laminating an aluminum foil and a resin layer,
The base layer, the said aluminum foil, and the innermost layer which consists of a polypropylene or polyethylene layer are laminated | stacked one by one, and a hydroxyl group is contained in the surface of at least the innermost layer side among the said aluminum foils. The laminated body for battery packaging in which the thin film coating layer which consists of resin which has frame | skeleton of polyvinyl alcohol, or its copolymerization resin is laminated | stacked. The method of claim 1,
The thin film coating layer is made of a metal fluoride or a derivative thereof and crosslinks a resin having a skeleton of a polyvinyl alcohol containing a hydroxyl group contained in the thin film coating layer or a copolymer resin thereof, and passivating the surface of the aluminum foil ( A laminate for battery packaging, comprising a material for passivation). The method of claim 1,
The laminated body for battery packaging, which is measured by the measuring method specified in JIS K7127, wherein the tensile breaking elongation of the laminate is 50% or more in either the MD direction or the TD direction. The method of claim 1,
The said thin film coating layer is a battery exterior laminated body which is crosslinked or amorphous, and has been water-resistant by heat processing. The method of claim 1,
The base material layer and the aluminum foil are bonded through a urethane adhesive, and the aluminum foil and the innermost layer are bonded through any one of a urethane adhesive, an acid-modified polyolefin resin, and an epoxy group-containing polyolefin resin. The method of claim 1,
The thickness of the said innermost layer is 20 micrometers or more and 40 micrometers or less, and also the adhesive strength of the said aluminum foil and the said innermost layer is 20 N / inch or more as measured by the peeling measuring method A prescribed | regulated to JIS C6471. , Battery laminate.

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