KR101712990B1 - Flexible cell pouch and secondary battery including the same - Google Patents

Abstract

Innermost layer; An intermediate layer formed on the innermost layer; A barrier layer formed on the intermediate layer; An extrusion resin layer formed on the barrier layer; And an outermost layer formed on the extruded resin layer, wherein the outermost layer comprises a nylon resin, and the extruded resin layer is provided with a flexible cell pouch including a polyethylene-based resin and an adhesive.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a flexible cell pouch and a secondary battery including the flexible cell pouch.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flexible cell pouch and a secondary battery including the same. More particularly, the present invention relates to a flexible cell pouch having excellent bendability and barrier properties, and a secondary battery including the same.

In general, a cell such as a lithium ion secondary battery is embedded in a metal can. The metal can is mainly made of aluminum (Al), and has a cylindrical shape or a rectangular shape (rectangular parallelepiped shape) through press working.

However, the metal can has a restriction that the outer wall is rigid and the shape of the cell itself is determined by the shape of the metal can. In order to overcome such a limitation, a flexible cell pouch has been developed and used. Generally, flexible cell pouches are manufactured in a multi-layered structure in consideration of gas barrier property, electrolyte resistance, heat adhesion, and the like. Fig. 1 shows a cross-sectional structural view (laminated structure) of a flexible cell pouch according to the prior art.

Referring to FIG. 1, generally, a flexible cell pouch comprises an innermost layer 2; An intermediate layer 4; A barrier layer (6) for gas barrier; And an outermost layer (8). The innermost layer 2 is located at the innermost portion of the flexible cell pouch and contacts the contents, that is, the cell. The intermediate layer 4 is formed to stabilize the heat resistance and cold resistance of the battery, and a polypropylene resin is mainly used. The barrier layer 6 is intended to block gas entering and out along with mechanical strength, and an aluminum foil (Al foil) is mainly used. The outermost layer 8 is for protecting the barrier layer 6 and it is mainly composed of a polyethylene terephthalate (PET) resin and / or a nylon resin in consideration of heat resistance, pinhole resistance and abrasion resistance Is used.

On the other hand, in recent years, attention has been paid to flexible pouches having excellent trends in miniaturization and bending properties, and ultra-thin flexible cellular pouches are required. In order to form a thin flexible flexible cell pouch, the thickness of the barrier layer 6 is reduced. When the thickness of the barrier layer 6 is thin, not only the barrier property is lowered but also the external force is continuously applied to the flexible cell pouch Holes may be formed in the barrier layer 6 and even cell pouches may be torn.

In addition, secondary batteries applied to flexible devices currently require higher bending properties than general cell phones. This is because a secondary battery used in a flexible device generally needs to be repeatedly bent and flattened after being mounted on a flexible device.

In addition, a flexible cell pouch mainly used for a cell phone, an electric automobile, etc., is formed to a maximum extent in order to improve the capacity of a battery, and an electrode group is accommodated in the formed cell pouch to manufacture a secondary battery have. However, holes are formed in the barrier layer 6 in the above-described molding process, so that barrier properties are deteriorated and problems such as loss of function as a battery occur.

Korean Patent Registration No. 10-0645607

The present invention relates to a flexible cell pouch for forming an extruded resin layer containing an extruded polyethylene resin between an outermost layer of a flexible cell pouch and a barrier layer to improve bendability and barrier property of the extruded resin cell, Battery.

In one embodiment to achieve the object of the present invention, the innermost layer; An intermediate layer formed on the innermost layer; A barrier layer formed on the intermediate layer; An extrusion resin layer formed on the barrier layer; And an outermost layer formed on the extruded resin layer, wherein the outermost layer includes nylon resin, and the extruded resin layer is provided with a flexible cell pouch including a polyethylene resin and an adhesive.

In an exemplary embodiment, the extrusion resin layer may comprise 70 to 80 parts by weight of a polyethylene-based resin and 20 to 30 parts by weight of an adhesive based on the total weight of the extrusion resin layer.

In an exemplary embodiment, the barrier layer comprises aluminum and may have a thickness of 9-15 [mu] m.

In an exemplary embodiment, the polyethylene-based resin is at least one selected from the group consisting of low density polyethylene (LDPE), linear low density polyethylene (LDPE), and high density polyethylene (HDPE) . ≪ / RTI >

In an exemplary embodiment, the adhesive may be at least one copolymer selected from the group consisting of ethylene monomers, propylene monomers, modified ethylene monomers and modified propylene monomers.

In an exemplary embodiment, the adhesive may be a tie resin.

In an exemplary embodiment, the extrusion resin layer may have a thickness of 10 to 20 占 퐉.

In an exemplary embodiment, the innermost layer comprises a casting polypropylene (CPP) or polyethylene (PE) resin, and the intermediate layer comprises a polypropylene (PP) resin .

In an exemplary embodiment, the flexible cell pouch may be bendable.

In one embodiment of the present invention, a secondary battery including the flexible cell pouch may be provided.

The flexible cell pouch according to embodiments of the present invention includes an extruded resin layer formed between an outermost layer and a barrier layer. The extruded resin layer is excellent in barrier property and has improved adhesion to a flexible polyethylene resin and / or barrier layer Lt; / RTI > Accordingly, even when the thickness of the barrier layer is about 15 탆 or less, the bendability and the gas barrier property of the battery including the barrier layer can be improved.

1 is a cross-sectional view of a flexible cell pouch according to the prior art.
2 is a cross-sectional view of a flexible cell pouch according to an embodiment of the present invention.
3 is a photograph showing the results of an experiment of bending test of a battery including outermost layers made of a PET resin and a nylon resin, respectively.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Although the embodiments of the present invention have been described with reference to the accompanying drawings, it is to be understood that the same is by way of illustration and example only and is not to be construed as limiting the scope of the present invention.

As used herein, the term "cell " refers to a battery, and includes all kinds of batteries such as a secondary battery such as a lithium ion battery, a lithium polymer battery, and a portable battery.

In the present specification, the term "cell pouch" refers to a structure in which a cell component such as an anode, a cathode, and a separator is impregnated with an electrolyte solution. The cell pouch includes gas barrier properties, Thermal adhesiveness and the like are processed in the form of a bag or a box.

As used herein, " barrier " means the ability to block underwater from outside the cell.

In this specification, " flexibility " means a degree of warpage of the cell and / or the cell pouch, and the cell and / or flexible cell pouch can be easily bent as the bendability is better.

Flexible cell pouch

2 is a cross-sectional view of a flexible cell pouch according to an embodiment of the present invention.

Referring to FIG. 2, the flexible cell pouch according to an embodiment of the present invention includes an innermost layer 12 sequentially stacked; An intermediate layer 14; A barrier layer 16; An extruded resin layer 17; And an outermost layer (18).

The innermost layer 12 may include a sealing resin for heat bonding as a cell is housed (embedded) and then adhered (thermally fused) by heat to provide sealing.

The sealing resin is not limited as long as it can be fused (thermally adhered) by heat, and it may preferably be a resin having heat resistance, insulation property, electrolyte resistance and / or cold resistance.

The sealing resin may preferably be selected from low melting point resins which can be thermally fused at a low temperature.

In the exemplary embodiment, polyethylene (PE) based resin may be coated on the innermost layer 12 for adhesion to each other, and a casted polypropylene (CPP) film may be used as the sealing resin. . The intermediate layer 14 serves to assist the innermost layer 14 adjacent to the innermost layer 12, and the heat resistance and cold resistance of the battery can be stabilized.

 In an exemplary embodiment, the intermediate layer 14 may comprise a polypropylene (PP) based resin. More specifically, the intermediate layer 14 may comprise at least one polypropylene (PP) system selected from homo-PP, PP co-polymer and PP ter-polymer, And may include a material formed by mixing polyethylene (PE) or ethylene vinyl acetate (EVA) or the like in the polypropylene (PP) system. In general, polypropylene (PP) based resins are excellent in thermal adhesiveness (sealability) and insulation, and are excellent in mechanical properties such as tensile strength, rigidity and surface hardness, and chemical resistance such as electrolyte resistance, Lt; / RTI >

In an exemplary embodiment, the intermediate layer 14 may have a thickness of about 5 to 20 [mu] m.

The barrier layer 16 is not limited as long as it is a metal having gas barrier properties. The barrier layer 16 can block external moisture, air, and gas generated therein. The barrier layer 16 may include at least one selected from a metal thin film and a metal deposition layer. The metal thin film may be a metal foil or the like and the metal vapor deposition layer may be a separate plastic film such as a film made of polyethylene terephthalate (PET), polyethylene (PE), or polypropylene (PP) For example, by vacuum evaporation.

The metal constituting the barrier layer 16, specifically, the metal constituting the metal thin film or the metal deposition layer may be aluminum (Al), iron (Fe), copper (Cu), nickel (Ni) (A single metal or a mixture of single metals) selected from the group consisting of tin (Sn), zinc (Zn), indium (In) and tungsten (W), or two or more alloys selected therefrom . The metal may be selected from aluminum (Al) or aluminum alloy (Al alloy). In addition, for the corrosion resistance, the barrier layer 16 may be surface treated with phosphoric acid, chromium, or the like.

In an exemplary embodiment, the barrier layer 16 may have a thickness of 15 [mu] m or less.

Preferably, the barrier layer 16 may have a thickness of 9 to 15 占 퐉. When the thickness of the barrier layer 16 is 9 mu m or less, the secondary battery is not easily realized as a cell pouch. When the thickness of the barrier layer 16 is 15 mu m or more, .

The extruded resin layer 17 contains a polyethylene-based resin and an adhesive and can improve the bendability of the flexible cell pouch.

The extruded resin layer 17 may include 70 to 80 parts by weight of a polyethylene resin and 20 to 30 parts by weight of an adhesive based on the total weight of the extruded resin layer.

In an exemplary embodiment, the polyethylene-based resin may specifically be a low density polyethylene (LDPE), a linear low density polyethylene (LDPE), a high density polyethylene (HDPE), or the like. The polyethylene-based resin generally has a softening property than that of a polypropylene-based resin, and is known to have excellent impact resistance, low temperature-resistant brittleness, flexibility and the like. Accordingly, the barrier layer 16 can be protected when the polyethylene-based resin is used in the extrusion resin layer 17.

In an exemplary embodiment, the adhesive may be excellent in adhesion to the barrier layer 16 and / or the outermost layer 18, and specifically may be formed from a group consisting of an ethylene monomer, a propylene monomer, a modified ethylene monomer and a modified propylene monomer ≪ / RTI > and at least one selected from the group consisting of the copolymer.

Preferably, a tie resin can be used as the adhesive. Generally, adhesion between a metal and a polymer material having a different polarity from that of a film is not excellent. On the other hand, the tie resin is a polymer composed of a main chain made of propylene monomers and a side chain composed of ethylenic monomers bonded thereto, or a polymer composed of a main chain made of ethylenic monomers and a side chain made of propylene- Structure. ≪ / RTI > That is, the tie resin may have both characteristics of a polypropylene resin and a polyethylene resin. Accordingly, when the extruded resin layer 17 includes a polyethylene-based resin and a tie resin, the properties of the polypropylene-based resin of the tie resin can improve the adhesion with the polyethylene-based resin. In addition, the characteristics of the polyethylene resin and the polypropylene resin of the tie resin can contribute to improving the adhesion between the barrier layer 16 and the outermost layer 18. In addition, since the tie resin is generally excellent in durability, it can protect the barrier layer 16 and / or the outermost layer 18 when used together with the polyethylene-based resin. In addition, the tie resin is excellent in properties such as chemical resistance and electrical insulation, and can improve the electrical characteristics of the cell pouch when used as a component of the cell pouch.

In an exemplary embodiment, the extrusion resin layer 17 may have a thickness of about 10 to 20 占 퐉.

The outermost layer 18 can protect the barrier layer 16. The outermost layer 18 is preferably made of a material having excellent abrasion resistance and heat resistance, cold resistance, pinhole resistance, insulation property, solvent resistance and / or moldability (a shape when a flexible cell pouch is processed into a predetermined shape Retainability), and the like. Specifically, the outermost layer 18 may include one or more resins selected from nylon resin, polyethylene terephthalate (PET) resin, polyolefin resin, and the like. Here, the polyolefin-based resin may be exemplified by polyethylene (PE) and polypropylene (PP).

In an exemplary embodiment, the outermost layer 18 may preferably comprise a nylon resin.

In an exemplary embodiment, the outermost layer 18 may have a thickness of about 5 to 25 [mu] m.

In the exemplary embodiment, an adhesive layer may be additionally formed between the outermost layer 18 and the extrusion resin layer 17. [ At this time, the adhesive layer may include a commonly used adhesive, and the thickness of the adhesive layer may be about 2 to 3 mu m.

The flexible cell pouch according to an embodiment of the present invention may include an extrusion resin layer 17 including a polyethylene resin and an adhesive between the barrier layer 16 and the outermost layer 18. [ Since the extruded resin layer 17 contains a flexible polyethylene-based resin, the bendability of the flexible cell pouch finished product including the extruded resin layer 17 can be improved. In addition, when the bending property of the flexible cell pouch finished product is improved, a problem that a pinhole due to insufficient bending property of the cell may be improved.

In addition, since the extruded resin layer 17 contains a polyethylene-based resin having excellent barrier properties, barrier properties of the flexible cell pouch including the extruded resin layer 17 can also be improved.

Manufacturing method of flexible cell pouch

A method of fabricating a flexible cell pouch according to an embodiment of the present invention includes forming an outermost layer and a barrier layer; Extruding a polyethylene resin and an adhesive to form an extruded resin layer interposed between the outermost layer and the barrier layer; Forming an innermost layer; And extruding a polyethylene resin between the surface of the exposed barrier layer and the surface of the innermost layer to form an intermediate layer interposed between the innermost layer and the barrier layer. The detailed constituent components of the outermost layer, the extruded resin layer, the barrier layer, the intermediate layer and the innermost layer are the same as those of the above-described flexible cell pouches, and thus a detailed description thereof will be omitted.

First, an outermost layer is formed by using a nylon resin, a polyethylene terephthalate (PET) resin, a polyolefin resin, or the like. It is also possible to use a metal such as aluminum (Al), iron (Fe), copper (Cu), nickel (Ni), tin (Sn), zinc (Zn), indium (In) and tungsten .

Thereafter, a resin mixed with a polyethylene resin and an adhesive is extruded between the outermost layer and the barrier layer to form an extruded resin layer.

That is, the extrusion resin layer is formed through an extrusion coating process using a resin mixed with a polyethylene-based resin and an adhesive, and the outermost layer and the barrier layer are laminated via the extrusion resin layer.

Then, the surface of the barrier layer on which the outermost layer is not laminated is surface-treated. Specifically, the barrier layer can be surface-treated with phosphoric acid, chromium, or the like. This can improve the corrosiveness of the surface of the barrier layer exposed in the air.

Thereafter, an innermost layer is formed by using a non-oriented polypropylene film, a polyethylene resin, or the like.

Subsequently, a polypropylene resin is extruded between the innermost layer and the surface-treated barrier layer to form an intermediate layer interposed between the innermost layer and the barrier layer. Accordingly, the barrier layer and the innermost layer can be laminated via the intermediate layer.

Accordingly, the cell pouch including the innermost layer, the intermediate layer, the barrier layer, the extruded resin layer, and the outermost layer sequentially stacked can be manufactured through the above-described processes.

Hereinafter, the present invention will be described in more detail with reference to Examples. It is to be understood by those skilled in the art that these embodiments are only for illustrating the present invention and that the scope of the present invention is not construed as being limited by these embodiments.

Example 1

An outermost layer having a thickness of about 12 mu m was formed using nylon resin, and a barrier layer having a thickness of about 9 mu m was formed using aluminum.

Thereafter, an adhesive is coated on the surface of the outermost layer, and the outermost layer and the barrier layer are laminated together to form a laminate. Thereafter, the surface of the barrier layer not lapped with the outermost layer was subjected to surface treatment using chromium. Thereafter, a non-oriented polypropylene film was used to form an innermost layer having a thickness of about 25 to 28 mu m. Thereafter, a polypropylene resin was extruded between the innermost layer and the laminate to form an intermediate layer interposed between the innermost layer and the laminate, and the laminate and the innermost layer were laminated together. At this time, the intermediate layer was formed to have a thickness of about 15 mu m. Thus, a cell pouch having a flat shape including an innermost layer, an intermediate layer, a barrier layer, and an outermost layer sequentially stacked and unformed was produced. Then, an electrode group was inserted into the cell pouch to prepare a secondary battery.

Example 2

An outermost layer having a thickness of about 15 mu m was formed using nylon resin, and a barrier layer having a thickness of about 9 mu m was formed using aluminum. Thereafter, a resin mixed with a polyethylene resin and a tie resin was extruded between the outermost layer and the barrier layer to form an extruded resin layer having a thickness of about 15 μm. Thus, a laminate in which a barrier layer, an extruded resin layer and an outermost layer were sequentially laminated was formed.

Thereafter, the exposed surface of the barrier layer was surface-treated with chromium. Thereafter, a non-oriented polypropylene film was used to form an innermost layer having a thickness of about 28 μm. Thereafter, a polypropylene resin was extruded between the innermost layer and the laminate to form an intermediate layer interposed between the innermost layer and the laminate, and the laminate and the innermost layer were laminated together. At this time, the thickness of the intermediate layer was made to have a thickness of 15 μm. Thus, a cell pouch having a flat shape including an innermost layer, an intermediate layer, a barrier layer, an extruded resin layer, and an outermost layer sequentially laminated and in a non-forming state was produced. Then, an electrode group was inserted into the cell pouch to prepare a secondary battery.

Comparative Example 1

In Example 1, a cell pouch was fabricated under the same conditions except that an outermost layer having a thickness of about 15 mu m was formed using PET resin instead of nylon resin, and then a secondary battery including the cell pouch was manufactured.

Comparative Example 2

In Example 2, a cell pouch was produced under the same conditions except that an extruded resin layer was not formed, and then a secondary battery including the same was manufactured.

Comparative Example 3

In Example 2, a cell pouch was fabricated under the same conditions except that the barrier layer was formed to have a thickness of about 20 탆, and a secondary battery including the cell pouch was fabricated.

Experimental Example 1: Measurement of bending property and cell capacity according to use of nylon resin

The secondary batteries prepared according to Example 1 and Comparative Example 1 were each fixed to a bendability tester, bent at an angle of 25R, and then bent and repeatedly bendability tested. Here, 25R means the radius of curvature of a sphere having a radius of 2.5 cm. The results are shown in FIG. 3 and Table 1. Particularly, in the battery capacity test in Table 1, after setting the secondary battery capacity before the bendability test to 100% (standard), the battery capacity at the bendability test was measured and displayed.

Number of bendability tests performed Battery Capacity Test Results (%) PET resin (Comparative Example 1) Nylon resin (Example 1) 50 95 95 1,000 51.9 85.2 2,000 37.1 84.1 3,000 1.6 85 4,000 0 83.2 5,000 0 84.6 6,000 0 86 7,000 0 85.3 8,000 0 84 9,000 0 84.8 10,000 0 0

Referring to FIG. 3, in the case of a secondary battery including a cell pouch manufactured according to Comparative Example 1, it was confirmed that the inside of the cell was broken as a result of performing the bending test 2,000 times or 3,000 times. On the other hand, it was confirmed that the secondary battery including the cell pouch manufactured according to Example 1 was not broken even after 10,000 times bending test, and the external shape was maintained. Accordingly, when the outermost layer includes a nylon layer, it is confirmed that the outermost layer is more excellent in bending property than the case where the outermost layer contains PET resin.

In addition, as shown in Table 1, in the case of the secondary battery manufactured according to Comparative Example 1, the battery capacity was 1.6% in the bending test of about 3,000 times, which is very insufficient. In addition, when the bendability test was performed about 4,000 times, the battery was disconnected and the battery capacity could not be measured. In contrast, in the case of the secondary battery manufactured according to Example 1, when the bendability test was performed about 9,000 times, the battery capacity was about 84.8%, which is excellent. Thus, when the outermost layer contains nylon resin, it was found that both the bendability test and the battery capacity test showed excellent results.

Experimental Example 2: Measurement of bending property and cell capacity according to presence or absence of extruded resin layer

The secondary batteries prepared according to Example 2 and Comparative Example 2 were each fixed to a bendability tester, bent and bent at an angle of 25R, and then bending test was repeatedly performed. Here, 25R means the radius of curvature of a sphere having a radius of 2.5 cm. Table 2 shows the cell capacity values according to the number of times of the bendability tests. At this time, after setting the battery capacity of the secondary battery before the bendability test to 100% (standard), the battery capacity at the bendability test was measured and displayed.

Number of bendability tests performed Battery Capacity Test Results (%) Example 2 Comparative Example 2 50 98 95 1,000 95.4 85.2 2,000 91 84.1 3,000 88.3 85 4,000 86.4 83.2 5,000 85 84.6 8,000 84 86 9,000 85.8 85.3 10,000 84.5 84 12,000 83.2 0 15,000 83.6 0 17,000 82.1 0 20,000 81.4 0

As can be seen from Table 2, in the case of the secondary battery manufactured according to Comparative Example 2, the battery capacity was smaller than that of the secondary battery manufactured according to Example 2 after the bending test of about 50 times or more. In addition, in the case of the secondary battery manufactured according to Comparative Example 2, after the bending test of about 10,000 times or more, the battery was broken and the battery capacity could not be measured. In contrast, in the case of the secondary battery manufactured according to Example 2, even when the bendability test was performed about 20,000 times, the battery did not break and showed a battery capacity of about 80% or more before the bendability test. As a result, it was confirmed that the secondary battery including the extruded resin layer showed excellent results in both the bendability test and the battery capacity test.

Experimental Example 3: Measurement of bending property and cell capacity according to aluminum thickness

The secondary batteries prepared according to Example 2 and Comparative Example 3 were each fixed to a bendability tester and bent and twisted at an angle of 25R to repeat the bending test. Here, 25R means the radius of curvature of a sphere having a radius of 2.5 cm. In addition, the battery capacity value according to the number of times of the bending test was measured at this time, and is shown in Table 3. At this time, the secondary battery capacity before the bendability test was set to 100% (standard), and the battery capacity values at the respective bendability tests were displayed.

Number of bendability tests performed Battery Capacity Test Results (%) Comparative Example 3 Example 2 50 88 98 1,000 75.4 95.4 2,000 68.2 91 3,000 0 88.3 4,000 0 86.4 5,000 0 85 8,000 0 84 9,000 0 85.8 10,000 0 84.5 12,000 0 83.2 15,000 0 83.6 17,000 0 82.1 20,000 0 81.4

As shown in Table 3, in the case of the secondary battery manufactured according to Comparative Example 3, the battery capacity was smaller than that of the secondary battery manufactured according to Example 2 after the bending test of about 50 times or more. In addition, after performing the bending test more than 1,000 times, it was confirmed that the battery capacity is less than 80%, which is the minimum standard required by the battery maker. On the other hand, in the case of the secondary battery manufactured according to Example 2, even when the bendability test was performed about 20,000 times, the battery did not break and showed a battery capacity of about 80% or more before the bendability test. As a result, it was confirmed that when the thickness of the barrier layer was about 20 占 퐉, which was 15 占 퐉 or more, the battery capacity sharply decreased at the time of the bendability test.

2, 12: innermost layer 4, 14: middle layer
6, 16: barrier layer 17: extruded resin layer
8, 18: outermost layer

Claims (10)

Innermost layer;
An intermediate layer formed on the innermost layer;
A barrier layer formed on the intermediate layer;
An extrusion resin layer formed on the barrier layer; And
And an outermost layer formed on the extruded resin layer,
Wherein the outermost layer comprises a nylon resin, the extrusion resin layer comprises a polyethylene-based resin and an adhesive,
Wherein the barrier layer has a thickness of 9 to 15 占 퐉. The flexible cell pouch for a flexible secondary battery according to claim 1, wherein the barrier layer has a thickness of 9 to 15 占 퐉. The method according to claim 1,
Wherein the extruded resin layer comprises 70 to 80 parts by weight of a polyethylene resin and 20 to 30 parts by weight of an adhesive based on the total weight of the extruded resin layer. The method according to claim 1,
Wherein the barrier layer comprises aluminum. The method according to claim 1,
The polyethylene resin may be at least one selected from the group consisting of low density polyethylene (LDPE), linear low density polyethylene (LDPE), and high density polyethylene (HDPE) . The method according to claim 1,
Wherein the adhesive is at least one copolymer selected from the group consisting of an ethylene monomer, a propylene monomer, a modified ethylene monomer, and a modified propylene monomer. 6. The method of claim 5,
The adhesive has a polymer structure composed of a main chain made of propylene-based monomers and a side chain made of ethylenic monomers bonded thereto, or a polymer structure composed of a main chain made of ethylene-based monomers and a side chain made of propylene- Flexible cell pouch for flexible secondary battery. The method according to claim 1,
Wherein the extruded resin layer has a thickness of 10 to 20 占 퐉. The method according to claim 1,
Wherein the innermost layer comprises a non-oriented polypropylene (CPP) based film or a polyethylene (PE) resin, and the intermediate layer is a flexible cell pouch for a flexible secondary battery including a polypropylene (PP) . The method according to claim 1,
Wherein the flexible cell pouch for the flexible secondary battery is a flexible cell pouch for a flexible secondary cell having bendability. A flexible secondary battery comprising the flexible cell pouch for a flexible secondary battery according to any one of claims 1 to 9.

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