KR101381598B1 - Aluminium pouch film for the secondary battery, the pack containing the same, the secondary battery containing the same and the manufacturing method of the same - Google Patents

Abstract

The present invention relates to an aluminum pouch film for a secondary battery and a method of manufacturing the same. The aluminum pouch film for a secondary battery includes an aluminum layer; an outer resin layer formed on the first surface of the aluminum; a first bonding layer bonded to the outer resin layer and the aluminum; an inner resin layer formed in the second surface of the aluminum layer; and a copolymer layer formed between the inner resin layer and the aluminum; and a second bonding layer bonding the copolymer layer to the inner resin layer. [Reference numerals] (1) Outer resin layer; (2) First bonding layer; (3) Aluminum layer; (4) Copolymer layer; (5) Second bonding layer; (6) Inner resin layer

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum pouch film for a secondary battery, a packaging material containing the same, a secondary battery including the same, and a method for manufacturing the same.

The present invention relates to an aluminum pouch film for a secondary battery and a method for manufacturing the same, and more particularly, compared to the conventional technology, in spite of omitting an aluminum surface treatment step with respect to a conventional secondary battery pouch film. It is related with manufacture of the aluminum pouch film for secondary batteries which improves electrolyte resistance and insulation.

The secondary battery refers to a lithium secondary battery, and is a battery used for an electric vehicle including a portable terminal device such as a notebook, a smart phone, a tablet PC, a video camera, a hybrid vehicle, a smart grid for energy storage, At the same time, research is under way to overcome various environmental factors such as harsh thermal environment and mechanical impact. Unlike a can-type packaging material used in conventional packaging materials, a packaging material used for such a lithium battery has a multilayer structure (for example, an inner resin layer, an aluminum layer, and an outer layer A resin layer) is used as a pouch for a secondary battery. A commonly used secondary battery pouch film is made of polyethylene (PE), casted polypropylene (cPP), polypropylene (PP), or the like, which has a heat- An inner resin layer composed of an adhesive layer made of a polyolefin or a copolymer thereof, an aluminum layer serving as a metal foil layer serving as a base layer for maintaining mechanical strength and a barrier layer for moisture and oxygen, A functional polymer film such as polyethylene terephthalate (PET) resin, polyethylene naphthalate (PEN), nylon resin or liquid crystal polymer (LCP) forms an outer resin layer, Structure.

The pouch type secondary battery has flexibility in shape and has an advantage that a secondary battery of the same capacity can be realized with a smaller volume and mass. Unlike the can type, however, the pouch type uses a soft pouch as a container, which can be damaged in various processes for various reasons. For example, in the process of housing the electrode assembly in the pouch, protruding portions such as electrode tabs and electrode leads may damage the internal PP and CPP layers of the pouch, such as cracks, Layer is exposed, and in this case, a side reaction occurs due to reactivity with the electrolyte solution. The aluminum layer exposed to the electrolytic solution may be corroded by causing a chemical reaction with oxygen or moisture, which is penetrated or diffused into the inside of the battery, and a corrosive gas is generated, thereby causing a swelling phenomenon There is a problem that will occur. More specifically, LiPF ₆ reacts with water and oxygen to produce hydrofluoric acid (HF), which is a corrosive gas. Such hydrofluoric acid may react with aluminum to cause a rapid exothermic reaction. When the aluminum is adsorbed on the aluminum surface due to the secondary reaction and penetrates into the inside of the structure, the brittleness of the structure is increased and cracks of the pouch film occur even in a fine impact. The reaction between lithium and the atmosphere may cause ignition. Therefore, in order to prevent contact with aluminum even if corrosive hydrofluoric acid is generated as described above, various aluminum surface modification techniques have been researched.

As a conventional aluminum surface modification method, a method of performing a conversion treatment on an aluminum foil as disclosed in Korean Patent Publication No. 10-2001-7010231 is known, and an example of a conversion treatment is a chromate treatment. In particular, there are many chromate treatment methods such as a coating type chromate treatment and a chromate treatment by a dipping method. However, in the chromate treatment as described above, materials using hexavalent chromium as a main component have good functions. However, in terms of environmental aspects, it is necessary to use Cd, Pb and Hg, which are toxic environmental pollutants harmful to human and living organisms, It is one of the four heavy metals that have problems to be removed, which is an undesirable material. In addition, due to worldwide strong regulations on the use of hexavalent chromium, economic factors such as its manufacture, use, processing and disposal have been continuously increasing, and research and development has been made on alternative materials and alternative processes. As a result of research and development, it has been generalized to perform chromate treatment using trivalent chromium that is relatively safe for living organisms compared to hexavalent chromium. However, since the function equivalent to hexavalent chromium is hardly obtained, There is a problem that the chromate treatment is not preferable as an environmental aspect. Further, the treating agent used in the chemical conversion treatment often accompanies corrosion of the coating apparatus, which not only limits the coating apparatus but also tends to lead to deterioration of the working environment. Furthermore, in order to improve the adhesion of the treatment agent, a step of immersing the substrate with acid or alkali and performing degreasing and etching must be provided during the manufacturing process. However, the cost of these steps is high and the manufacturing cost of the cell- It is necessary to find a way to maintain the performance as a secondary battery packaging material while omitting the aluminum surface treatment process.

KR10-2001-7010231

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide an aluminum pouch manufacturing process in which an aluminum surface treatment process is omitted to provide an environmentally friendly and economical advantage and a battery is exposed to physical, chemical, Cracking of the adhesive layer inside the pouch is suppressed even when the pouch is used, and the moldability, the insulating property and the electrolytic solution resistance are excellent.

The present invention is an aluminum layer; An outer resin layer formed on the first surface of the aluminum layer; A first adhesive layer for bonding the aluminum and the external resin layer; An inner resin layer formed on the second surface of the aluminum layer; A copolymer layer formed between the aluminum layer and the internal resin layer; And it provides a secondary battery aluminum pouch film comprising a second adhesive layer for bonding the copolymer layer and the internal resin layer.

The present invention also relates to a method of manufacturing a semiconductor device comprising the steps of: a) preparing an aluminum layer; b) forming an outer resin layer on the first surface of the aluminum layer; c) forming a copolymer layer on the second surface of the aluminum layer; d) provides a method of manufacturing an aluminum pouch film for a secondary battery comprising the step of forming an inner resin layer on the copolymer layer.

The present invention also provides a packaging material comprising an aluminum pouch for a secondary battery.

The present invention also encompasses a secondary battery comprising an aluminum pouch film for a secondary battery.

The use of the aluminum pouch film for a secondary battery according to the present invention can prevent delamination by suppressing cracks in the adhesive layer inside the pouch even if exposed to physical, chemical, or electrical stress, Therefore, it is possible to reduce the risk of explosion of the battery due to the generation of gas in the inside of the battery or the explosion due to the high temperature. In addition, the aluminum surface treatment process, which does not involve the chemical surface treatment of aluminum foil, is applied to the film by applying an adhesive containing a part of a special monomer modified with a monomer component, Can be omitted, which is preferable from the viewpoint of environment friendliness and economy.

1 illustrates a structure of an aluminum pouch film for secondary batteries according to a preferred embodiment of the present invention.
2 illustrates the mechanism of the present invention.

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

In the aluminum pouch film for secondary batteries of the present invention, as shown in Figure 1, the aluminum layer 3, the outer resin layer (1) formed on the first surface of the aluminum layer, the first bonding the aluminum layer and the outer resin layer The adhesive layer 2, the copolymer layer 4 formed on the second surface of the aluminum layer, the inner resin layer 6 located on the innermost side of the film, and the second adhesive layer 5 for bonding the copolymer layer and the inner resin layer 5 ) There is a strong bond between the aluminum layer and the copolymer layer 4 by phosphate groups.

The phosphate mechanism between the group and the aluminum layer is an initial defect is formed by hydrogen bonding between the layer of aluminum oxide and aluminum phosphate on the surface as in the second, here applied to the column main surface in the water out (H ₂ O) is located This forms a strong bond leading to RPO-Al. At this time, since there is a hydroxyl group between the copolymer layer and the inner resin layer, in particular, a strong bond with the polyurethane-based adhesive is formed.

Hereinafter, each constitution of the aluminum pouch for a secondary battery of the present invention will be described in detail.

Aluminum layer

In the aluminum pouch film for a secondary battery of the present invention, the aluminum layer (3) can be preferably a soft aluminum foil, more preferably, an aluminum foil containing iron Use a foil. The iron-containing aluminum foil may contain 0.1 to 9.0% by mass, more preferably 0.5 to 2.0% by mass, based on 100% by mass of the total aluminum foil. When the content of iron in the aluminum foil is less than 0.1 mass%, the ductility of the aluminum layer is deteriorated. When the content of aluminum exceeds 9.0 mass%, the formability is deteriorated. The aluminum foil to be used for the aluminum layer can be etched or degreased on its surface in order to improve the adhesion with the internal resin layer, but it can be omitted for the purpose of reducing the processing speed. The thickness of the aluminum layer is preferably 10 to 100 占 퐉, more preferably 30 to 50 占 퐉 in consideration of workability, oxygen and moisture barrier properties. If the above range is not satisfied, if it is less than 10 탆, it tears easily, and the electrolytic resistance and insulating property are deteriorated, and if it exceeds 100 탆, the moldability is deteriorated.

The outer resin layer

In the aluminum pouch film for a secondary battery of the present invention, the outer resin layer (1) corresponds to a portion in direct contact with hardware, and therefore is preferably a resin having insulating properties. Therefore, as the resin used as the external resin layer, a polyester resin such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, copolymer polyester and polycarbonate is used, or a nylon film is used , And it is particularly preferable to use a nylon film. The nylon film is excellent in heat resistance, cold resistance and mechanical strength as well as excellent in rupture strength, pinhole property, gas barrier property and the like, and thus is mainly used as packaging film. Specific examples of the nylon film include polyamide resins such as nylon 6, nylon 66, copolymers of nylon 6 and nylon 66, nylon 610, and polymetaxylene imine amide (MXD6). When the external resin layer is laminated, the thickness of the laminated external resin layer is preferably 10 to 30 탆 or more, particularly preferably 12 to 25 탆. If it is less than 10 탆, the physical property tends to be lost and tear easily. If it is more than 30 탆, the moldability is deteriorated.

The first adhesive layer

In the aluminum pouch film for a secondary battery of the present invention, as the first adhesive layer, a polyurethane-based adhesive containing a polyol component as a main component and further containing an isocyanate compound or a derivative thereof as a curing agent component may be used. The first adhesive layer is preferably 2 to 10 占 퐉, more preferably 3 to 5 占 퐉 in consideration of adhesiveness to the external resin layer and thickness after molding. When the range is not satisfied, when the thickness is less than 2 탆, the tackiness is poor. When the thickness is more than 10 탆, cracks may occur.

The inner resin layer

In the aluminum pouch film for a secondary battery of the present invention, a polyolefin such as polyethylene (PE) or polypropylene (PP) or a copolymer thereof may be used as the internal resin layer. When polyolefin such as PE or PP or a copolymer thereof is used for the polymer layer, not only the physical properties required as a packaging material for a secondary battery such as good heat-seizing property, moisture-proofing property and heat resistance, but also good workability such as lamination Do. The thickness of the polymer layer of the internal resin layer is preferably 20 to 60 占 퐉, more preferably 30 to 50 占 퐉 in consideration of moldability, insulation property, electrolyte resistance, and the like. If the above range is not satisfied, there may arise a problem that moldability, insulation, and electrolytic solution resistance are deteriorated.

The copolymer layer

In the aluminum pouch film for secondary batteries of the present invention, the copolymer layer may be a copolymer comprising a monomer composed of a hydroxy group on one side and a phosphate, and preferably VPA (Vinyl Phosphonic Acid). ) And AA (Acrulic Acid) can be used. In the case of containing the monomer, the aluminum thin layer and PO ₄ ^{2 −} of the phosphate group form a strong bond, and the hydrophilic group, the hydroxyl group, induces a firm bond with the inner resin layer through the adhesive. Adhesion can be further improved compared to the chromate method. In addition, since the monomer forms a copolymer layer, water resistance and penetration from the electrolytic solution are suppressed, thereby improving the electrolyte resistance. Therefore, since the aluminum pouch film for secondary batteries of this invention contains the said copolymer layer, although the aluminum chromate surface treatment which is a prior art is omitted, the performance of electrolytic resistance and adhesiveness does not fall. It is preferable that it is 2-30 micrometers, and, as for the said copolymer layer in consideration of adhesiveness with an internal resin layer, the thickness after shaping | molding, etc., it is more preferable. If the above range is not satisfied, the adhesiveness and the electrolyte resistance are inferior in the case of less than 2 μm, and the flexibility of the film may be in the case of exceeding 30 μm.

The second adhesive layer

In the aluminum pouch film for secondary batteries of the present invention, the second adhesive layer may be polyester, polyether, urethane, polyesterurethane, polyolefin, polyethyleneimine, cyanoacrylate, isocyanate, imide, Adhesives made of silicone resins or modified substances thereof and mixtures thereof can be used. It is preferable that it is 2-30 micrometers, and, as for the said 2nd adhesive layer in consideration of adhesiveness with an inner layer, thickness after shaping | molding, etc., it is more preferable that it is 3-15 micrometers. If the above range is not satisfied, adhesiveness is poor when the thickness is less than 2 탆, and flexibility is low when the thickness is more than 30 탆. When the inner resin layer and the aluminum layer are laminated on the second adhesive layer, there is no particular limitation, but lamination can be preferably performed by using a dry lamination method or an extrusion lamination method.

The present invention also relates to a method of manufacturing a semiconductor device comprising the steps of: a) preparing an aluminum layer; b) forming an outer resin layer on the first surface of the aluminum layer; c) forming a copolymer layer on the second surface of the aluminum layer; d) may be prepared, including forming an inner resin layer on the copolymer layer.

Further, the present invention can provide a packaging material comprising the aluminum pouch film for a secondary battery.

The present invention also provides a secondary battery comprising the aluminum pouch film for the secondary battery.

Hereinafter, a specific example in which an aluminum pouch film for a secondary battery is manufactured will be described.

Example  1 and Comparative Example  One, Comparative Example  2: Fabrication of aluminum pouch film

The aluminum pouch film for a secondary battery of the present invention will be described in more detail with reference to Examples.

[Example 1]

An aluminum foil (manufactured by the same aluminum company) having a thickness of 40 mu m was slit into an area of 30 cm x 20 cm, and then subjected to water washing to remove dust on the surface.

First, to form a copolymer layer on the second surface of the aluminum foil, a 5: 1 mixture of VPA (Vinyl Phosphonic Acid) (Rhodia) and AA (Acrylic Acid) was applied to a thickness of 5 μm, and then 3 at 120 ° C. Daily heat treatment was performed.

Subsequently, in order to laminate the outer resin layer on the first surface of the aluminum foil, a 4 μm-thick polyurethane adhesive resin (manufactured by Hichem Co., Ltd.) was applied, followed by dry laminating the nylon 6 (manufactured by Hyosung Co., Ltd.) having a thickness of 25 μm. The nylon was laminated on the aluminum layer, and then aged at 40 ° C. for 7 days.

Thereafter, a polyurethane adhesive (manufactured by Mitsui) was applied to a thickness of 4 μm in order to laminate the inner resin layer on the second surface of the aluminum foil on which the copolymer layer was formed, and then 40 μm thick polypropylene (manufactured by Okamoto) Dry lamination was performed to laminate polypropylene on aluminum and then aged at 40 ° C. for 5 days.

[Comparative Example 1]

An aluminum foil (manufactured by the same aluminum company) having a thickness of 40 mu m was slit into an area of 30 cm x 20 cm, and then subjected to water washing to remove dust on the surface.

First, a polyurethane adhesive resin (manufactured by HiChem Co., Ltd.) having a thickness of 4 탆 was applied to laminate the outer resin layer on the first surface of the aluminum foil, and then a nylon 6 (manufactured by Hyosung Co., Ltd.) having a thickness of 25 탆 was subjected to dry lamination Nylon was laminated on the aluminum layer, and then aged at 40 DEG C for 7 days.

Thereafter, in order to laminate the inner resin layer on the second surface of the aluminum foil, a polyurethane adhesive (manufactured by Mitsui) was applied at a thickness of 4 μm, followed by dry laminating of polypropylene having a thickness of 40 μm (manufactured by Okamoto). Polypropylene was laminated on aluminum and then aged at 40 ° C. for 5 days.

[Comparative Example 2]

An aluminum foil (manufactured by the same aluminum company) having a thickness of 40 mu m was slit into an area of 30 cm x 20 cm, and then subjected to water washing to remove dust on the surface. Subsequently, the washed aluminum foil was immersed in 5% sulfuric acid solution and then degreased, and then the surface was activated by immersion in 5% sodium hydroxide solution. Thereafter, the aluminum foil was immersed in an immersion liquid containing an aluminum trivalent chromium film-forming agent (manufactured by ATOTECH Co.) and subjected to chemical treatment for 5 minutes.

First, a polyurethane adhesive resin (manufactured by HiChem Co., Ltd.) having a thickness of 4 탆 was applied to laminate the outer resin layer on the first surface of the aluminum foil, and then a nylon 6 (manufactured by Hyosung Co., Ltd.) having a thickness of 25 탆 was subjected to dry lamination Nylon was laminated on the aluminum layer, and then aged at 40 DEG C for 7 days.

Thereafter, in order to laminate the inner resin layer on the second surface of the aluminum foil, an adhesive (manufactured by Mitsui Co., Ltd.) using only a polyurethane base was coated in a thickness of 4 mu m as compared with Example 1, Propylene (manufactured by Okamoto) was subjected to dry lamination treatment, and polypropylene was laminated on aluminum, followed by aging at 40 占 폚 for 5 days.

Electrolytic solution resistance  evaluation

The aluminum pouch films for secondary batteries according to Example 1 and Comparative Examples 1 and 2 were each cut into 2 cm x 4 cm pieces. The test pieces were sealed with a LiPF ₆ electrolyte solution (manufactured by RICHM Co., Ltd.) The film was taken every 4 hours until after 24 hours, and whether the film was peeled off was visually observed to evaluate the electrolyte resistance.

4 hours 8 hours 12 hours 16 hours 20 hours 24 hours Example 1 ○ ○ ○ ○ ○ ○ Comparative Example 1 ○ △ △ × × × Comparative Example 2 ○ ○ ○ ○ ○ ○

○: No peeling occurred

DELTA: Partial peeling occurred

×: Peeling occurred

As shown in Table 1, in Example 1, peeling did not occur as well as in Comparative Example 1 that does not include a copolymer layer, and peeling did not occur at a level equivalent to that of Comparative Example 2 which was subjected to a separate chemical conversion treatment.

Adhesive evaluation

The aluminum pouch films for secondary batteries according to Example 1 and Comparative Examples 1 and 2 were molded into 20 cm x 1.5 cm (width x length), respectively, and the adhesion strength between the inner resin layer and the aluminum layer was measured by a texture analyzer of Stable Micro Systems. It was.

Adhesive evaluation Example 1 ◎ Comparative Example 1 △ Comparative Example 2 ○

◎: 12-15 N

○: 8-11 N

△: 4-7 N

As shown in Table 1, Example 1 has a higher adhesive strength than Comparative Example 1 does not include a copolymer layer, it can be seen that has a superior adhesive strength than Comparative Example 2 subjected to a separate chemical conversion treatment.

Claims (15)

Aluminum layer;
An outer resin layer formed on the first surface of the aluminum layer;
A first adhesive layer for bonding the aluminum and the external resin layer;
An inner resin layer formed on the second surface of the aluminum layer;
A copolymer layer formed between the aluminum layer and the internal resin layer; And
A second adhesive layer for bonding the copolymer layer and the internal resin layer,
The copolymer layer is a secondary battery aluminum pouch film, characterized in that one side comprises a monomer modified with a phosphate group. The method of claim 1, wherein the outer resin layer is any one or more selected from the group consisting of polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, copolymerized polyester, polycarbonate and nylon film The aluminum pouch film for secondary batteries characterized by the above-mentioned. The method of claim 2, wherein the nylon film is nylon 6, nylon 66, a copolymer of nylon 6 and nylon 66, nylon 610, polymethacylsilane amidamide (MXD6) any one or more selected from the group consisting of The aluminum pouch film for secondary batteries characterized by the above-mentioned. The aluminum pouch film for secondary batteries of claim 1, wherein the first adhesive layer comprises a polyol component, and further comprises a polyurethane-based adhesive further comprising an isocyanate compound or a derivative thereof as a curing agent component. delete The aluminum pouch film for secondary batteries of claim 1, wherein the monomer comprises a monomer on which the other side thereof is modified with a hydroxyl group. The aluminum pouch film for secondary batteries of claim 1, wherein the monomer component is VPA (Vinyl Phosphonic Acid) and AA (Acrulic Acid). The aluminum pouch film for secondary batteries of claim 1, wherein the inner resin layer is made of polyolefin or a copolymer of polyolefin. The aluminum pouch film for secondary batteries of claim 8, wherein the polyolefin is polyethylene (PE) or polypropylene (PP). The method of claim 1, wherein the second adhesive layer is polyester, polyether, polyurethane, polyesterurethane, polyolefin, polyethyleneimine, cyanoacrylate, isocyanate, imide, silicone resin or the like An aluminum pouch film for secondary batteries comprising any one or more of a modified substance and a mixture thereof. a) preparing an aluminum layer;
b) forming an outer resin layer on the first surface of the aluminum layer;
c) forming a copolymer layer on the second surface of the aluminum layer; And
d) forming an inner resin layer on the copolymer layer,
The copolymer layer is a method of manufacturing an aluminum pouch film for secondary batteries, characterized in that one side comprises a monomer modified with a phosphate group. delete 12. The method of claim 11, wherein the monomer comprises a monomer on which the other side is modified with a hydroxyl group. The packaging material containing the aluminum pouch film for secondary batteries of any one of Claims 1-4 and 6-10. A secondary battery comprising the aluminum pouch film for secondary battery according to any one of claims 1 to 4 and 6 to 10.

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