JP5066776B2 - Battery packaging materials - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
It is a packaging material used for exterior bodies such as batteries, fuel cells, capacitors, capacitors, etc. that have moisture resistance and content resistance and that have liquid or solid organic electrolytes (polymer polymer electrolytes). The present invention relates to a battery packaging material having a material.
[0002]
[Prior art]
The battery in the present invention includes a device including an element that converts chemical energy into electric energy, for example, a lithium ion battery, a lithium polymer battery, a fuel cell, or a dielectric such as a liquid, a solid ceramic, or an organic substance. Including electrolytic capacitors such as liquid capacitors, solid capacitors, double layer capacitors.
Applications of the battery include personal computers, portable terminal devices (cell phones, PDAs, etc.), video cameras, electric vehicles, energy storage batteries, robots, satellites, and the like.
As the battery exterior body, a metal can obtained by pressing a metal into a cylindrical or rectangular parallelepiped container, or a laminate made of a composite film obtained by laminating a plastic film, a metal foil or the like into a bag shape. (Hereinafter referred to as an exterior body) was used.
There were the following problems as a battery outer package. In a metal can, since the outer wall of the container is rigid, the shape of the battery itself is determined. Therefore, since the hardware side is designed to match the battery, the size of the hardware using the battery is determined by the battery, and the degree of freedom in shape is reduced.
Therefore, it exists in the tendency to use the said bag-shaped exterior body. The material structure of the exterior body is at least a base material layer, a barrier layer, from the necessary physical properties, workability, economy, etc. as a battery.
It consists of an adhesive layer that adheres the sealant layer and each of the above layers, and an intermediate layer may be provided as necessary.
A pouch is formed from the laminated body of the above-described configuration of the battery, or at least one side is press-molded to form a battery storage portion to store the battery body, and the pouch type or embossed type (covering the cover) In the above, a necessary part of each peripheral edge is sealed by heat sealing to obtain a battery.
[0003]
[Problems to be solved by the invention]
In the formation of the exterior body by the laminate, depending on the type of the exterior body, the manufacturing process may be punched with a die set. When the packaging material to be punched is a laminate composed of a flexible material or a combination of materials of flexible different materials, burrs will not occur completely, or an uncut part will be formed in one part. In other words, productivity could be hindered due to failure to separate the extracted portion and the remaining portion.
In the battery packaging material of the present invention, a laminate comprising at least a base material layer, a barrier layer, and a sealant layer may be used.
An object of the present invention is to provide a battery packaging material having a configuration capable of maintaining the performance of a battery over a long period of time, and in particular, having a stable pullability in a manufacturing process of an exterior body.
[0004]
[Means for Solving the Problems]
The above problems can be solved by the following present invention. According to the first aspect of the present invention, a packaging material for forming a battery outer body in which a battery body is inserted and a peripheral portion is sealed by heat sealing is at least a base material layer, an adhesive layer 1, aluminum, a chemical conversion treatment layer, an adhesive layer. 2. A laminate composed of a PE-based sealant layer, wherein at least the PE-based sealant layer includes a blend layer single layer in which medium density polyethylene and linear low density polyethylene are blended, or the blend layer It consists of the packaging material for batteries characterized by having a multilayer structure. The invention described in claim 2, in which the adhesive layer 2 according to claim 1, characterized in that an adhesive layer by dry lamination method. The invention described in claim 3 is characterized in that the adhesive layer 2 described in claim 1 is a coating and baking layer of an acid-modified polyethylene emulsion. The invention described in claim 4 is characterized in that the adhesive layer 2 described in claim 1 is an extruded resin layer of acid-modified polyethylene.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
The battery packaging material of the present invention includes at least a base material layer, an adhesive layer, a chemical conversion treatment layer 1, aluminum, a chemical conversion treatment layer 2, an adhesive layer and a sealant layer in which the sealant layer is an acid-modified polyolefin layer. In the body, at least the sealant layer is made of a multi-layer structure including a medium density polyethylene layer so that the material has good removability. Hereinafter, it will be described in detail with reference to the drawings.
[0006]
1A and 1B are diagrams for explaining a battery packaging material according to the present invention, in which FIG. 1A is a cross-sectional view showing a layer structure, and FIG. 1B is a cross-sectional view showing another layer structure. FIGS. 2A and 2B are diagrams for explaining an embodiment in which a battery outer body is formed, in which FIG. 2A is a perspective view of the battery, and FIG. 2B is a perspective view of the battery body and the outer body before inserting the battery main body. (C) It is a top view which shows the extraction shape of an exterior body. FIG. 3 is a perspective view for explaining a pouch-type exterior body of a battery. FIG. 4 is a perspective view illustrating an embossed type exterior body of a battery. Figure 5 illustrates the molding in embossed type, (a) a perspective view, (b) embossing the molded outer body, (c) X ₂ -X ₂ parts cross-sectional view, with (d) Y ₁ part enlarged view is there. FIG. 6 is a diagram for explaining a method for mounting a lead wire film in bonding a battery packaging material and a lead wire.
[0007]
The battery packaging material forms an exterior body for packaging a main body of a lithium ion battery or the like. Depending on the form of the exterior body, a pouch type as shown in FIG. 3 and FIGS. There is an embossed type as shown in FIG. The pouch type includes three-side seals, four-side seals, and pillow types such as a pillow type. FIG. 3 illustrates a pillow type.
As shown in FIGS. 4A and 4D, the embossed type may be formed with a recess 7 on one side, or as shown in FIG. And may be sealed by heat-sealing the four sides of the periphery. There is also a type in which a concave portion is formed on both sides with a folding portion as shown in FIG. 4 (c), the battery is accommodated, and three sides are heat-sealed.
[0008]
When the battery packaging material is an embossed type, as shown in FIGS. 5 (a) to 5 (d), the laminated packaging material 10 is press-molded to form the recess 7.
[0009]
The battery packaging material is, for example, an embossed type as shown in FIG. 2A, and is made of nylon / adhesive layer / aluminum / adhesive layer / sealant layer, and the sealant layer is made of a polyethylene resin layer. 2 is an embossed type exterior body 5 as shown in FIG. 2 (b), for example, and the tray portion 5V and the lid portion 5F are integrated with each other via the folding line m. As a punching shape as the processing step, a shape T as shown in FIG. 2C is obtained, which is a punching step by a die set type punching die.
If the polyethylene-based resin forming the sealant layer is low-density polyethylene or linear low-density polyethylene, burrs are generated in the punched portion obtained by the die-set punching die, and the product is further defective. There was a case where productivity was hindered without removing the part.
[0010]
As a result of diligent research on the materials that do not cause defective punching, the inventors of the present invention have a good sealability by making the sealant layer of the battery packaging material into a multilayer sealant structure including at least a resin layer made of medium density polyethylene. The inventors have found that the material can be used and have completed the present invention.
[0011]
Examples of the polyethylene resin used as the multilayer sealant layer of the present invention include high density polyethylene, medium density polyethylene, low density polyethylene, linear low density polyethylene, ethylene-vinyl acetate copolymer, acid-modified polyethylene, and the like. Is a multilayer film composed of two or more resin layers including at least a medium density polyethylene layer.
As the acid-modified polypropylene resin, a random type polypropylene grafted with an unsaturated carboxylic acid can be used.
[0012]
More specifically, examples of the configuration of the sealant in the battery packaging material of the present invention include the following configurations.
・ MD + LL
・ MD / MD + LL
・ MD / MD + LL / LL
・ MD / MD + LL / MD
・ MD / LL / MD
・ LL / MD + LL / MD
・ MD + HD
LD and HD may be blended in each layer [abbreviation MD: medium density polyethylene, LL: linear low density polyethylene, LD: low density polyethylene, HD: high density polyethylene, + indicates blend, / indicates layer interface Indicates. ]
By adopting the sealant structure of the battery packaging material of the present invention, even if there is a die-set punching die in the processing step when manufacturing the battery outer package, troubles such as generation of burrs due to defective punching, undrawn parts, etc. Has been resolved.
[0013]
When the outer body of a lithium ion battery is an embossed type, it is formed by press molding in the side wall portion when it is formed by a sandwich lamination method, dry lamination method, coextrusion lamination method, thermal lamination method, etc. Delamination often occurs between the material layers, and delamination also occurs in a portion where the lithium ion battery main body is housed in an exterior body and its periphery is heat sealed.
Moreover, the surface of the inner surface of aluminum may be attacked by hydrogen fluoride generated by the reaction between the electrolyte, which is a component of the battery, and moisture, and delamination may occur.
[0014]
The present inventors have a good embossing formability, a laminated body in which delamination does not occur between the base material layer and the barrier layer at the time of embossing molding or heat sealing, and lithium having content resistance. As a result of diligent research on packaging materials that can be satisfied as an outer package for an ion battery, it has been found that it can be solved by forming a laminate using various laminating methods described below.
In the first method of laminating, delamination is performed by subjecting both surfaces of the barrier layer to chemical conversion and dry laminating the base material layer and the barrier layer, and the barrier layer and the sealant layer with a two-component curable adhesive. I found that it can be avoided. The two-component curable adhesive includes, for example, a main agent and a hardener, and the main agent includes at least two kinds of sebacic acid, isophthalic acid, terephthalic acid, octatanic acid, nonannic acid, undecanoic acid, and palmitic acid. A blend of an acid component, a polyester resin composed of an alcohol component containing at least one of ethylene glycol, hexanediol, and diethylene glycol, and a bisphenol A type epoxy resin, and the curing agent is composed of a polyisocyanate component.
[0015]
In the second laminating method, an acid-modified polyethylene emulsion liquid is applied to the chemical conversion treated surface 15 (2) by a roll coat method or the like, dried and baked at a temperature of 170 to 200 ° C., and then a sealant film. It was confirmed that the adhesive strength of the laminate was improved by laminating by thermocompression bonding.
The acid-modified polyethylene is unsaturated carboxylic acid grafted polyethylene.
[0016]
It was also confirmed that stable adhesive strength could be obtained by the following third laminating method.
For example, the base material layer 11 and one surface of the barrier layer 12 are dry-laminated, and the acid-modified polyolefin 13 is extruded onto the other surface (chemical conversion layer) of the barrier layer 12 as shown in FIG. When the layer 14 is sandwich-laminated or as a fourth laminating method, the acid-modified polyolefin resin 13 and the sealant layer are co-extruded to form a laminate, and the resulting laminate is used as the acid-modified polyolefin resin 13. By heating to a condition that is equal to or higher than the softening point, it was possible to obtain a laminate having a predetermined adhesive strength.
Specific heating methods in the third and fourth laminating methods include methods such as a hot roll contact method, a hot air method, a near or far infrared ray, and any heating method may be used in the present invention. As described above, it is sufficient that the adhesive resin can be heated to the softening point temperature or higher.
[0017]
Further, as another method, in the case of the sandwich lamination or coextrusion lamination, the bonding is also performed by heating to a condition in which the surface temperature of the barrier layer 12 on the sealant layer 14 side reaches the softening point of the acid-modified polyolefin resin. A laminate with stable strength could be obtained.
Although a polyethylene resin can be used as an adhesive resin, in this case, it is desirable to laminate the laminated surface of the extruded polyethylene molten resin film on the aluminum side while performing ozone treatment.
[0018]
In the battery packaging material of the present invention, for each of the layers in the laminate forming the outer package, film forming properties, lamination processing, final product secondary processing (pouching, embossing) suitability are improved and stabilized as appropriate. For this purpose, surface activation treatment such as corona treatment, blast treatment, oxidation treatment, and ozone treatment may be performed.
[0019]
Next, each layer which comprises the battery packaging material of this invention is demonstrated.
As shown in FIG. 1A, the battery packaging material of the present invention is a laminate composed of at least a base material layer 11, an adhesive layer 16, aluminum 12, a chemical conversion treatment layer 15, an adhesive layer 13d, and a multilayer sealant layer 14. When the exterior body to be described later is an embossed type, as shown in FIG. 1B, the laminate is a base material layer 11, an adhesive layer 16, a chemical conversion treatment layer 15 (1), aluminum. 12, the chemical conversion treatment layer 15 (2), the adhesive layer 13 d, and the multilayer sealant layer 14 are desirable.
The base material layer 11 in the outer package is made of stretched polyester or nylon film. At this time, examples of the polyester resin include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, copolymer polyester, polycarbonate, and the like. Can be mentioned. Examples of nylon include polyamide resin, that is, nylon 6, nylon 6,6, a copolymer of nylon 6 and nylon 6,6, nylon 6,10, polymetaxylylene adipamide (MXD6), and the like.
When the base material layer 11 is used as a battery, the base material layer 11 is a part that is in direct contact with the hardware. Considering the existence of pinholes in the film alone and the occurrence of pinholes during processing, the base material layer needs to have a thickness of 6 μm or more, and preferably 12 to 30 μm.
[0020]
The base material layer 11 can also be laminated in order to improve pinhole resistance and insulation when used as a battery outer package.
When the base material layer is laminated, the base material layer includes at least one resin layer of two or more layers, and the thickness of each layer is 6 μm or more, preferably 12 to 30 μm. Examples of laminating the base material layer include the following 1) to 8).
1) Stretched polyethylene terephthalate / stretched nylon 2) Stretched nylon / stretched stretched polyethylene terephthalate In addition, packaging material mechanical suitability (transport stability in packaging machines and processing machines), surface protection (heat resistance, electrolyte resistance) ) When the battery exterior body is made an embossed type as a secondary processing, the base material layer is protected when the embossing is applied for the purpose of reducing the frictional resistance between the mold and the base material layer during embossing. In order to achieve this, the base material layer may be multilayered, and a fluororesin layer, an acrylic resin layer, a silicone resin layer, a polyester resin layer, or a resin layer made of a blend thereof may be provided on the surface of the base material layer. preferable.
For example,
3) Fluorine resin / stretched polyethylene terephthalate (Fluorine resin is a film or formed by drying after liquid coating)
4) Silicone resin / stretched polyethylene terephthalate (silicone resin is a film or formed by drying after liquid coating)
5) Fluorine-based resin / stretched polyethylene terephthalate / stretched nylon 6) Silicone-based resin / stretched polyethylene terephthalate / stretched nylon 7) Acrylic resin / stretched nylon (Acrylic resin is film-like or cured after drying by liquid coating)
8) Acrylic resin + polysiloxane graft acrylic resin / stretched nylon (acrylic resin is film-like or cured by drying after liquid coating)
[0021]
The barrier layer 12 is a layer for preventing water vapor from entering the inside of the battery from the outside, stabilizing the pinhole and processability (pouching, embossing formability) of the barrier layer alone, and being resistant to resistance. In order to have a pinhole, a metal such as aluminum or nickel having a thickness of 15 μm or more, or a film on which an inorganic compound such as silicon oxide or alumina is deposited may be used. The aluminum is 80 μm.
In order to further improve the generation of pinholes and to make the battery exterior body type an embossed type, in order to prevent the occurrence of cracks in the embossing molding, the present inventors have made a material for aluminum used as a barrier layer. However, when the iron content is 0.3 to 9.0% by weight, preferably 0.7 to 2.0% by weight, the extensibility of aluminum is better than that of aluminum not containing iron. The present inventors have found that the occurrence of pinholes due to bending is reduced as a laminate, and the side wall can be easily formed when the embossed type exterior body is formed. When the iron content is less than 0.3% by weight, effects such as prevention of pinholes and improvement of embossing formability are not observed, and the iron content of the aluminum exceeds 9.0% by weight. In such a case, the flexibility as aluminum is hindered, and the bag-making property is deteriorated as a laminate.
[0022]
In addition, aluminum produced by cold rolling changes its flexibility, waist strength and hardness under annealing (so-called annealing treatment) conditions, but the aluminum used in the present invention is harder than the non-annealed hard-treated product. Aluminum that tends to be soft, with some or complete annealing, is preferred.
The degree of flexibility, waist strength and hardness of aluminum, that is, the conditions for annealing, may be appropriately selected in accordance with processability (pouching, embossing). For example, in order to prevent wrinkles and pinholes during embossing, it is desirable to use soft aluminum annealed according to the degree of forming.
[0023]
The present inventors have been able to obtain a laminate that is satisfactory as the packaging material by subjecting the front and back surfaces of aluminum, which is the barrier layer 12 of the battery packaging material, to chemical conversion. Specifically, the chemical conversion treatment is to form an acid-resistant film such as phosphate, chromate, fluoride, triazine thiol compound, etc. Among the acid-resistant film-forming substances, phenol resin, chromium fluoride (3) Phosphoric acid chromate treatment using a compound and three components of phosphoric acid is good. Or the chemical conversion treatment agent which contains metals, such as molybdenum, titanium, a zircon, or a metal salt in the resin component containing a phenol resin at least was favorable. Due to the formation of the acid-resistant film, delamination between aluminum and the base material layer during embossing is prevented, and the aluminum surface is dissolved and corroded by hydrogen fluoride generated by the reaction between the battery electrolyte and moisture. In particular, the aluminum oxide existing on the surface of aluminum is prevented from being dissolved and corroded, and the adhesion (wetting property) of the aluminum surface is improved, and the base material layer 11 and the aluminum 12 at the time of embossing and heat sealing. The effect of preventing delamination on the inner surface of aluminum by hydrogen fluoride generated by the reaction between electrolyte and moisture was obtained.
As a result of conducting a chemical conversion treatment on the aluminum surface using various substances and studying the effect thereof, among the acid-resistant film forming substances, it is composed of three components of a phenol resin, a chromium fluoride (3) compound, and phosphoric acid. The treatment with phosphoric acid chromate using the sample was good.
Or the chemical conversion treatment agent which contains metals, such as molybdenum, titanium, a zircon, or a metal salt in the resin component containing a phenol resin at least was favorable.
[0024]
When the exterior body is a pouch type, the chemical conversion treatment of aluminum may be performed on one side only on the sealant layer side or on both sides of the base material layer side and the sealant layer side. When the battery outer body is an embossed type, delamination between the aluminum and the base material layer during embossing can be prevented by subjecting both surfaces of the aluminum to chemical conversion treatment.
[0025]
The sealant layer in the battery packaging material of the present invention has a multilayer structure including a medium density polyethylene layer as described above.
[0026]
【Example】
The battery packaging material of the present invention will be described more specifically with reference to examples.
(1) Configuration of battery packaging material The following configurations were used in all of the examples, reference examples, and comparative examples.
ON 25 μm / DL 3 μm / double-side chemical conversion treatment ALM 40 μm / adhesive (3 μm) or adhesive resin (15 μm) / sealant: 30 μm
[Abbreviation ON: biaxially stretched nylon film, DL: dry laminate, ALM: aluminum]
When the sealant layer or the layer constituting the sealant layer is made of a blend resin, the blend ratio is expressed in parts by weight.
(2) Chemical conversion treatment In the chemical conversion treatment applied to the barrier layer of the exterior body, in both the Examples, Reference Examples and Comparative Examples, an aqueous solution composed of a phenol resin, a chromium fluoride (3) compound and phosphoric acid is used as a treatment liquid. It was applied by a coating method and baked under conditions where the film temperature was 180 ° C. or higher. The application amount of chromium is 5 mg / m ² (dry weight).
(3) Type of exterior body Each of Examples , Reference Examples and Comparative Examples was evaluated as an embossed exterior body. The shape was a single-sided embossed type, and the shape of the concave portion (cavity) of the mold was 30 mm × 50 mm and the depth was 5.0 mm, and the moldability was evaluated by press molding. When encapsulating the electrolyte solution in the confirmation of leakage, an unmolded laminate was used as the lid.
(4) Abbreviation LL: Linear low density polyethylene HD: High density polyethylene MD: Medium density polyethylene /: Layer interface in the case of multilayer +: Blend [Example 1]
Chemical conversion treatment was performed on both sides of 40 μm aluminum, and a stretched nylon film (thickness 25 μm) was bonded to one side of the chemical conversion treatment by a dry laminating method, and then a sealant film was dried on the other surface of the chemical conversion treatment aluminum. The laminate obtained by laminating was designated as Sample Example 1. The sealant film is a film having a thickness of 30 μm formed by using <LL50 part + MD50 part> as a raw material resin. The obtained laminate was used as a tray by embossing, and an unmolded laminate was used as a cover material as an exterior.
[Example 2]
Chemical conversion treatment was performed on both sides of 40 μm aluminum, and a stretched nylon film (thickness 25 μm) was bonded to one side of the chemical conversion treatment by a dry laminating method, and then a sealant film was dried on the other surface of the chemical conversion treatment aluminum. The laminate obtained by laminating was designated as Sample Example 2. The sealant film is MD [1] / <MD50 part + LL50 part> [3] / LL [1] (in the case where the LL layer side is the innermost resin layer and the multilayer, the layer described later is the innermost resin layer in the same manner below. A film having a thickness of 30 μm. The numerical value in [] after each layer indicates the layer thickness μm in the case of a multilayer. The laminated body was made into a tray by embossing, and the laminated body that was not molded was used as a cover material to make an exterior body.
[Example 3]
Chemical conversion treatment was performed on both sides of 40 μm aluminum, and a stretched nylon film (thickness 25 μm) was bonded to one side of the chemical conversion treatment by a dry laminating method, and then a sealant film was dried on the other surface of the chemical conversion treatment aluminum. The laminate obtained by laminating was designated as Sample Example 3. The sealant film is a film having a thickness of 30 μm composed of three layers of MD [1] / <MD50 parts + LL50 parts> [3] / MD [1]. The obtained laminate was embossed to form a tray, and the unmolded laminate was used as a cover material to form an exterior body.
[ Reference Example 1 ]
Chemical conversion treatment was performed on both sides of 40 μm aluminum, and a stretched nylon film (thickness 25 μm) was bonded to one side of the chemical conversion treatment by a dry laminating method, and then a sealant film was dried on the other surface of the chemical conversion treatment aluminum. The laminate obtained by laminating was used as Sample Reference Example 1 . The sealant film is a film having a thickness of 30 μm formed by using <MD50 part + HD50 part> as a raw material resin. The obtained laminate was embossed to form a tray, and the unmolded laminate was used as a lid to form an exterior.
[ Reference Example 2 ]
Both surfaces of aluminum 40 μm were subjected to chemical conversion treatment, and a stretched nylon film (thickness 25 μm) was bonded to one side of the chemical conversion treatment by a dry laminating method, and then the other surface of the chemical conversion processed aluminum was coated with acid-modified polyethylene. The emulsion was coated and dried, further baked at a temperature of 190 ° C., and a laminate obtained by thermally laminating a sealant film (30 μm) on the baked surface was used as Sample Reference Example 2 . The sealant film is a film having a thickness of 30 μm formed by using <MD50 part + HD50 part> as a raw material resin. The obtained laminate was used as a tray by embossing, and an unmolded laminate was used as a cover material as an exterior.
[ Reference Example 3 ]
Chemical conversion treatment was applied to both sides of 40 μm aluminum, and a stretched nylon film (thickness 25 μm) was bonded to one side of the chemical conversion treatment by a dry laminating method. Next, acid-modified polyethylene resin was applied to the other side of the conversion-treated aluminum. A laminate obtained by sandwiching a sealant film with an adhesive resin of 15 μm and heating it above the softening point of acid-modified polyethylene was designated as Sample Reference Example 3 . The sealant film is a film having a thickness of 30 μm formed by using <MD50 part + HD50 part> as a raw material resin. The laminated body was made into a tray by embossing, and the laminated body that was not molded was used as a cover material to make an exterior body.
[0027]
[Comparative Example 1]
Chemical conversion treatment was performed on both sides of 40 μm aluminum, and a stretched nylon film (thickness 25 μm) was bonded to one side of the chemical conversion treatment by a dry laminating method, and then a sealant film was dried on the other surface of the chemical conversion treatment aluminum. The laminate obtained by laminating was used as Sample Comparative Example 1. The sealant film is a film having a thickness of 30 μm formed by using LL as a raw material resin. The laminated body was made into a tray by embossing, and the laminated body that was not molded was used as a cover material to make an exterior body.
[Comparative Example 2]
Chemical conversion treatment was performed on both sides of 40 μm aluminum, and a stretched nylon film (thickness 25 μm) was bonded to one side of the chemical conversion treatment by a dry laminating method, and then a sealant film was dried on the other surface of the chemical conversion treatment aluminum. The laminate obtained by laminating was used as Sample Comparative Example 2. The sealant film is a film having a thickness of 30 μm formed by using MD as a raw material resin. The obtained laminate was embossed to form a tray, and the unmolded laminate was used as a lid to form an exterior.
[Comparative Example 3]
Both surfaces of aluminum 40 μm were subjected to chemical conversion treatment, and a stretched nylon film (thickness 25 μm) was bonded to one side of the chemical conversion treatment by a dry laminating method, and then the other surface of the chemical conversion processed aluminum was coated with acid-modified polyethylene. The emulsion was coated and dried, further baked at a temperature of 190 ° C., and a laminate obtained by thermally laminating a sealant film (thickness 30 μm) on the baked surface was used as Sample Comparative Example 3. The sealant film is a film having a thickness of 30 μm formed by using LL as a raw material resin. The obtained laminate was used as a tray by embossing, and an unmolded laminate was used as a cover material as an exterior.
[Comparative Example 4]
Chemical conversion treatment was applied to both sides of 40 μm aluminum, and a stretched nylon film (thickness 25 μm) was bonded to one side of the chemical conversion treatment by a dry laminating method. Next, acid-modified polyethylene resin was applied to the other side of the conversion-treated aluminum. A laminate obtained by sandwiching a sealant film with an adhesive resin of 15 μm and heating it above the softening point of acid-modified polyethylene was designated as Sample Comparative Example 4. The sealant film is a film having a thickness of 30 μm formed by using LL as a raw material resin. The laminated body was made into a tray by embossing, and the laminated body that was not molded was used as a cover material to make an exterior body.
[0028]
<Evaluation items>
1) Formability Shows the number of specimens in which pinholes occurred when 50 specimens were molded to a depth of 5.0 mm.
2) Cutability When the die set is removed, the cut amount at which the lower surface of the male mold (upper mold) and the upper surface of the female mold (lower mold) are the same height is regarded as the zero point, and then completely cut into a predetermined shape from there. Indicates the required cutting depth (mm). It means that it is a material which is hard to cut, so that there is much cutting amount.
3) Confirmation of leakage After the electrolyte solution was sealed in the exterior bodies prepared in Examples, Reference Examples and Comparative Examples and stored at 60 ° C. for 2 weeks, the presence or absence of leakage was confirmed.
[0029]
<Result>
In all of Examples 1 to 3 and Reference Examples 1 to 3, the moldability was good and no pinholes were generated. Moreover, the cut property is as follows,
Example 1 0.4 mm
Example 2 0.3 mm
Example 3 0.2 mm
Reference Example 1 0.2mm
Reference example 2 0.1 mm
Reference Example 3 0.4mm
There was no leakage. At least, in the reference example , the cut property was improved as compared with the comparative example in which LL was used as a sealant and was manufactured by the same laminating method. In addition, there was no leakage in the storage test in which the electrolyte was sealed. Comparative Example 1, Comparative Example 3 and Comparative Example 4 have a configuration in which the sealant layer is LL, but the moldability was good, but the cut properties were 0.5 mm, 0.4 mm, and 1.0 mm, respectively. It was a poor fit. On the other hand, Comparative Example 2 had a configuration in which the sealant layer was MD , but the cutability was as good as 0.2 mm, but the moldability was poor, and pinholes were confirmed in 3 samples out of 50 samples. It was. In the comparative example, there was no leakage in the storage test in which the electrolytic solution was sealed.
[0030]
【Effect of the invention】
The at least sealant layer of the battery packaging material of the present invention has a blend layer single layer in which medium density polyethylene and linear low density polyethylene are blended, or a multilayer structure including the blend layer, thereby improving embossability. The die set punching suitability in the exterior body forming process could be improved without damaging.
[Brief description of the drawings]
1A and 1B are diagrams illustrating a battery packaging material of the present invention, in which FIG. 1A is a cross-sectional view showing a layer structure, and FIG. 1B is a cross-sectional view showing another layer structure.
FIGS. 2A and 2B are diagrams for explaining an example of extraction when forming a battery outer package, in which FIG. 2A is a perspective view of the battery, and FIG. 2B is a perspective view of the battery main body and the outer package before the battery main body is inserted; (C) It is a top view which shows the extraction shape of an exterior body.
FIG. 3 is a perspective view for explaining a pouch-type exterior body of a battery.
FIG. 4 is a perspective view illustrating an embossed type exterior body of a battery.
[5] will be described molding in embossed type, (a) a perspective view, (b) embossing the molded outer body, (c) X ₂ -X ₂ parts cross-sectional view, with (d) Y ₁ part enlarged view is there.
FIG. 6 is a diagram for explaining a method for attaching a lead wire film in bonding a battery packaging material and a lead wire.
[Explanation of symbols]
T Disconnected wire m Folded wire 1 Battery 2 Battery body 3 Cell (power storage unit)
4 Lead wire (electrode)
DESCRIPTION OF SYMBOLS 5 Exterior body 5V Tray part 5F Lid part 6 Lead wire film 7 Recessed part 8 Side wall part 9 Seal part 10 Laminated body (battery packaging material)
11 Base material layer 12 Aluminum (barrier layer)
DESCRIPTION OF SYMBOLS 13 Adhesive layer of barrier layer and sealant layer 14 Sealant layer S1 Outer layer S2 of sealant layer Intermediate layer S3 of sealant layer Inner layer 15 of sealant layer Chemical conversion treatment layer 16 Dry laminate layer 20 of base material layer and barrier layer Press forming section 21 Male type 22 Female type 23 Cavity

Claims (4)

The packaging material for forming the battery outer body in which the battery body is inserted and the periphery is sealed by heat sealing is composed of at least a base material layer, an adhesive layer 1, aluminum, a chemical conversion treatment layer, an adhesive layer 2, and a PE sealant layer. The PE-based sealant layer is composed of at least a blend layer in which medium density polyethylene and linear low density polyethylene are blended, or a multilayer structure including the blend layer. Battery packaging material. The battery packaging material according to claim 1, wherein the adhesive layer 2 is an adhesive layer formed by a dry lamination method. The battery packaging material according to claim 1, wherein the adhesive layer (2) is an application-baked layer of an acid-modified polyethylene emulsion. The battery packaging material according to claim 1, wherein the adhesive layer 2 is an extruded resin layer of acid-modified polyethylene.

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