KR101491873B1 - Pouch-Type Flexible Rechargeable Film Battery And Method of Manufacturing the Same - Google Patents

Abstract

A pouch type flexible film battery and a manufacturing method thereof are provided. The film battery comprises a positive electrode structure including a positive electrode pouch, a positive electrode conductive carbon layer and a positive electrode layer, a negative electrode structure including a negative electrode pouch, a negative electrode conductive carbon layer and a negative electrode layer, and a polymer electrolyte layer between the positive electrode and the negative electrode structure, The polymer electrolyte layer may be a gel electrolyte including a cellulose-based polymer.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a pouch-type flexible film battery,

The present invention relates to a film battery, and more particularly, to a pouch-type flexible film battery and a manufacturing method thereof.

Interest in flexible devices such as rolled-up displays, e-paper, flexible LCDs, flexible OLEDs, and recessed PCs is growing rapidly. Accordingly, a power supply device for a flexible device is also required to have a flexible characteristic.

In consideration of the use environment, the flexible power supply device must be manufactured to have durability in addition to the above flexible characteristics. For example, even under repetitive bending operations, the flexible power supply must be made such that 1) no cracks are created in each of its components, and 2) no separation between its components occurs . In addition, for a flexible power supply to successfully enter the market, its manufacturing cost must be reduced. In order to reduce such manufacturing costs, it is advantageous that the film battery is manufactured not only by simple but also continuous manufacturing processes.

The flexible characteristics can be satisfied by fabricating the components of the flexible power supply using materials having ductility characteristics. However, according to the presently proposed techniques, it is difficult to simultaneously satisfy the durability and the flexible characteristics. For example, a polymer film having a flexible property (for example, polyethylene terephthalate) has been proposed as a packaging material for a film battery. However, since most polymer films do not completely block the permeation of gas or moisture, they do not have sufficient corrosion resistance to strong acids or strong bases, so technical problems such as electrolyte leakage or drying may occur.

Although some polymer films (e.g., polypropylene) have a sufficiently high corrosion resistance to strong acids or strong bases, they have other physical properties that lead to complexity in the manufacturing process of the film cell. For example, screen printing is a thin film forming method that can reduce manufacturing costs, but since polypropylene has low surface energy and hydrophobicity, film formation through screen printing is difficult to implement directly on polypropylene. In addition, according to the prior art, the contact characteristics between the electrodes constituting the film battery and the electrolyte deteriorate with the passage of time. For example, a problem has arisen that separation between the electrode and the electrolyte occurs or physical contact becomes poor.

SUMMARY OF THE INVENTION The present invention provides a pouch-type flexible film battery capable of satisfying durability and flexible characteristics at the same time.

SUMMARY OF THE INVENTION The present invention provides a pouch type flexible film battery having excellent adhesion between an electrode and an electrolyte.

SUMMARY OF THE INVENTION The present invention provides a pouch type flexible film battery capable of improving productivity in a manufacturing process.

Disclosure of Invention Technical Problem [8] The present invention provides a method of manufacturing a pouch-type flexible film battery capable of improving productivity in a manufacturing process.

The present invention provides a pouch-type flexible film battery comprising a polymer electrolyte layer containing a cellulosic polymer. Specifically, the film battery includes a negative electrode structure including a positive electrode structure including a positive electrode pouch, a positive electrode conductive carbon layer, and a positive electrode layer, a negative electrode pouch, a negative electrode conductive carbon layer, and a negative electrode layer, and a polymer electrolyte layer The polymer electrolyte layer may be a gel electrolyte including a cellulose-based polymer.

According to some embodiments, the polymer electrolyte layer may include a polymer matrix including the cellulose-based polymer and the strength-enhancing polymer. At this time, the weight ratio of the cellulose-based polymer to the strength-enhancing polymer may be 1:99 to 99: 1.

According to some embodiments, the cellulosic polymer is selected from the group consisting of cellulose, methyl cellulose, ethyl cellulose, butyl cellulose, hydroxypropyl cellulose, cellulose nitrate at least one of cellulose nitrate, cellulose acetate, cellulose acetate propionate, cellulose acetate butyrate, or carboxymethyl cellulose.

According to some embodiments, the strength-enhancing polymer is selected from the group consisting of polyvinylidene fluoride-based polymers, polyvinylchloride derivatives, acrylonitrile-based polymer derivatives, polyvinylacetate, polyvinylalcohol, A polyimide, a polysulfone, or a polyurethane. The polyvinylidene fluoride-based polymer may be at least one selected from the group consisting of polyvinylidenefluoride, copolymers of vinylidene fluoride and hexafluoropropylene, vinylidene fluoride and polyvinylidene fluoride, (Vinylidene fluoride-co-trifluoroethylene), a copolymer of vinylidene fluoride and polytetrafluoroethylene (polyvinylidene fluoride-co-tetrafluoroethylene) The acrylonitrile-based polymer derivative includes at least one of a copolymer of acrylonitrile and methyl methacrylate or polyacrylonitrile, and the acrylate-based polymer is selected from the group consisting of polymethylmethacrylate, polyethyl acrylate Polyethylacrylate, polyethylmethacrylate, polybutyl acrylate, (Polybutylacrylate) or polybutylene metadata may include at least one methacrylate (Polybutylmethacrylate).

According to some embodiments, the gel electrolyte may comprise a lithium salt. The lithium salt may be at least one selected from the group consisting of lithium perchlorate (LiClO ₄ ), lithium triflate (LiCF ₃ SO ₃ ), lithium hexafluorophosphate (LiPF ₆ ), lithium tetrafluoroborate (LiBF ₄ ), lithium trifluoromethanesulfonylimide _{(LiN (CF 3 SO 2)} 2) or may be at least one of the combinations thereof. In addition, the polymer electrolyte layer may further include an inorganic additive. The inorganic additive may be silica, talc, alumina _{(Al 2 O 3), TiO} 2, clay (Clay), or a zeolite, at least one of the combinations thereof.

According to some embodiments, at least one of the anode and cathode pouches may be surface treated to have an inner layer that is hydrophilic. At this time, the cathode conductive carbon layer or the cathode conductive carbon layer may be coated on the surface-treated surface of the inner layer. At least one of the anode and cathode pouches may further include an outer layer and an intermediate layer interposed between the inner layer and the outer layer. The outer layer and the inner layer may be a polymer film layer, and the intermediate layer may be a metal layer or a mixed layer of a metal and a polymer film.

According to some embodiments, the inner layer may be formed of at least one of amorphous polypropylene (c-PP), polyethylene, ethylene vinyl acetate (EVA), ethylene vinyl alcohol (EVOH), or combinations thereof. The outer layer may be formed of at least one of polyethylene terephthalate, polybutylene terephthalate, nylon, high density polyethylene (HDPE), oriented polypropylene (o-PP), polyvinyl chloride, polyimide, polysulfone, . Also, the metal layer for the intermediate layer is at least one of aluminum, copper, stainless steel, or their respective alloys, and the polymer film for the intermediate layer is selected from the group consisting of polyester, high density polyethylene, polyvinyl chloride (PVC), polyimide, Teflon Or at least one of these blends.

According to some embodiments, each of the positive electrode conductive carbon layer and the negative electrode conductive layer may comprise a conductive carbon and a polymer binder, and the weight ratio of the conductive carbon and the polymer binder is in the range of from 8.5: 1 to 9.9: 0.1 Lt; / RTI > The conductive carbon may be at least one of graphite, hard carbon, soft carbon, carbon fiber, carbon nanotube, carbon black, acetylene black, Ketjenblack or a combination thereof. The polymer binder may include polyvinylidene fluoride, At least one of vinylidene fluoride and hexafluoropropylene, a polyvinyl chloride, a cellulose-based polymer, polyethylene, polypropylene, ethylene vinyl acetate, polyvinyl alcohol, or a combination thereof, wherein the cellulosic polymer is selected from the group consisting of cellulose, And may be at least one of methyl cellulose, ethyl cellulose, butyl cellulose, hydroxypropyl cellulose, cellulose nitrate, cellulose acetate, cellulose acetate propionate, cellulose acetate butyrate or carboxymethyl cellulose.

According to some embodiments, the anode layer includes a cathode active material, a conductive material, and a binder, and the cathode layer may include a cathode active material, a conductive material, and a binder. At this time, the conductive materials of the anode layer and the cathode layer include at least one of graphite, hard carbon, soft carbon, carbon fiber, carbon nanotube, carbon black, acetylene black, Ketjenblack, , The positive electrode layer, and the negative electrode layer are selected from the group consisting of polyvinylidene fluoride, a copolymer of vinylidene fluoride and hexafluoropropylene, a polyvinyl chloride, a cellulosic polymer, a polyethylene, a polypropylene, an ethylene vinyl acetate, a polyvinyl Wherein the cellulose-based polymer is at least one selected from the group consisting of cellulose, methyl cellulose, ethyl cellulose, butyl cellulose, , Cellulosic Cellulose acetate propionate, cellulose acetate butyrate, or carboxymethyl cellulose.

The positive electrode active material may be a lithium alloy, a mixture of the lithium metal compounds, a solid solution of the lithium metal compounds, or a solid solution of the lithium metal compounds to which at least one of aluminum, iron, copper, titanium or magnesium is added, The oxide may be nano-sized olivine (LiFePO ₄ ), lithium cobalt oxide (LiCoO ₂ ), lithium nickel oxide (LiNiO ₂ ) or lithium manganese oxide (LiMn ₂ O ₄ ) coated with carbon particles.

The negative electrode active material may be at least one of a carbon-based material and a non-carbon-based material. The carbon-based material may include at least one of graphite, hard carbon or soft carbon, and the non-carbon material may be at least one selected from the group consisting of tin, silicon, lithium titanium oxide (Li _x TiO ₂ ) nanotubes, Oxide (Li ₄ Ti ₅ O ₁₂ ).

According to some embodiments, the weight ratio of the cathode active material, the conductive material, and the binder for the anode layer may be from 8: 1: 1 to 9.8: 0.1: 0.1, and the anode active material, The weight ratio of the conductive material and the binder may be from 8: 1: 1 to 9.8: 0.1: 0.1.

According to some embodiments, the anode layer includes a cathode active material, a conductive material, and a binder, and the cathode layer may be a lithium foil.

According to some embodiments, the cathode pouch and the cathode pouch may include inner layers that are thermally fused and in direct contact.

According to some embodiments, it may further comprise anode and cathode terminals respectively connected to the cathode conductive carbon layer and the cathode conductive carbon layer.

The present invention provides a method of manufacturing a pouch-shaped flexible film battery including a step of forming an adhesive gel polymer electrolyte layer. The method includes: forming a cathode structure including a cathode conductive layer and an anode layer sequentially formed on a first film; forming a cathode structure including a cathode conductive layer and a cathode layer sequentially formed on the second film; Forming a gel-type electrolyte layer including a cellulose-based polymer on at least one of the anode and cathode structures, and then bonding the anode and cathode structures. The step of bonding the positive electrode and the negative electrode structures may include bonding the first and second films to each other using the gel-like electrolyte layer as an adhesive layer using the heat fusion technique to adhere the positive electrode layer and the negative electrode layer to the gel- Step < / RTI >

According to some embodiments, the method of manufacture may be practiced using a roll-to-roll system. The roll-to-roll system may be configured to continuously perform the steps of forming the anode and cathode structures, forming the gel-like electrolyte, and adhering the anode and cathode structures.

According to some embodiments, at least one drying step may be performed. For example, the drying step may be performed after forming at least one of the cathode conductive layer, the anode layer, the cathode conductive layer or the cathode layer.

According to some embodiments, the cathode conductive carbon layer, the anode layer, the cathode conductive carbon layer, and the cathode layer may be formed using a screen printing technique.

According to some embodiments, the step of forming the gel-like electrolyte layer comprises preparing an electrolyte solution containing a polymer matrix and a liquid electrolyte dissolved in a co-solvent, coating the electrolyte solution on at least one of the anode and cathode structures , And drying the cosolvent. In this case, the polymer matrix may include a cellulose-based polymer and a strength-enhancing polymer, and the liquid electrolyte may include a lithium salt.

According to some embodiments, the co-solvent is selected from the group consisting of N-methylpyrrolidone (NMP), D-methylformamide (DMF), D-methylformacetate (DMAc), acetone, ethanol, methanol, propanol, Ethylene glycol monobutyl ether, diethylene glycol diethyl ether, diethylene glycol butyl vinyl ether, diethylene glycol monododecyl ether, diethylene glycol monohexadecyl ether, diethylene glycol monohexyl ether, diethylene glycol monooctyl ether, Diethylene glycol mono-octadecyl ether, diethylene glycol monophenyl ether, diethylene glycol monopropyl ether, or combinations thereof.

According to some embodiments, the step of preparing the electrolyte solution may further include adding an inorganic additive after blending the cellulose-based polymer and the strength-enhancing polymer, wherein the inorganic additive is silica, talc, alumina _{(Al 2 O 3), TiO} 2, clay (clay), or a zeolite, at least one of the combinations thereof may be.

According to some embodiments, before forming the anode conductive carbon layer and the cathode conductive carbon layer, the inner surfaces of the first and second films are surface treated Further steps can be carried out. The surface treatment step may be carried out using at least one of a corona discharge treatment, a plasma treatment, a silicate film formation through a flame treatment, or an oxide film formation through a coating process.

According to some embodiments, the gel-like electrolyte layer may include a first electrolyte layer formed on the anode structure and a second electrolyte layer formed on the cathode structure. In this case, the step of bonding the positive electrode and the negative electrode structures may include a step of bonding the first and second electrolyte layers to each other.

According to some embodiments, the step of adhering the anode and cathode structures may be conducted under atmospheric pressure conditions. Alternatively, the steps of forming the positive electrode conductive layer, the positive electrode layer, the negative electrode conductive layer, the negative electrode layer and the gel electrolyte layer, and adhering the positive electrode and negative electrode structures may be performed under atmospheric pressure conditions .

According to some embodiments, the step of bonding the anode and cathode structures comprises sealing the inner space in which the electrolyte layer is disposed by fusing the first and second films around the electrolyte layer, The electrolyte layer may be formed in the inner space before the sealing step.

The step of separating each of the film batteries by cutting the fused first and second films after the anode and cathode structures are bonded may be further performed.

According to the embodiments of the present invention, by using the pouch film as a substrate for current collector, it is possible to manufacture a sealed-type film battery having excellent flexibility and capable of simultaneously blocking gas and moisture permeation.

Further, a gel polymer material having excellent adhesion is used for the electrolyte layer. Accordingly, the film battery according to the present invention can have excellent adhesive holding properties. That is, the adhesion properties between the electrolyte layer and the electrode layers or between the electrolyte layers can be kept excellent.

Meanwhile, the pouch type flexible film battery according to the present invention can be implemented regardless of the output voltage. In particular, since the pouch film is used as a substrate for a current collector, the pouch type flexible film battery according to the present invention can be realized without a separate metallic positive terminal. For example, a non-metallic conductive carbon layer constituting the current collector may be extended and used as the positive electrode terminal.

In the manufacturing process, the pouch film is surface-treated to have hydrophilicity so that the conductive layer and the electrode layer can be directly coated on the pouch film. Accordingly, the film cells according to the present invention can be continuously manufactured through a reel-to-reel manufacturing process. In particular, since the facing inner layers of the pouch film, which are located around the electrode layer, can be thermally fused during the open reel manufacturing process, the manufacturing process of the film batteries according to the present invention can be automated, simplified and sequenced.

In addition, the gel polymer electrolyte layer having excellent adhesion can be coated on the electrode layer through the screen printing method. Since the electrolyte layer can be formed through a screen printing method and since the electrolyte layer interposed between the anode layer and the cathode layer has good adhesion, the process of bonding the anode and cathode structures can proceed through a roll-to-roll process .

On the other hand, according to some embodiments, since the film batteries according to the present invention can be manufactured without a pressure reduction process, the productivity in the manufacturing process can be greatly improved. According to other embodiments, the step of adhering the anode and cathode structures may be performed under a reduced pressure condition, but this step may also achieve excellent sealing characteristics through a simple method of heat-sealing the pouch film. As a result, it is possible to realize a film battery having excellent storage life and long life characteristics while ensuring simplicity in the manufacturing process.

1 is a perspective view exemplarily showing a pouch type flexible film battery according to some embodiments of the present invention.
2 is a perspective view exemplarily showing a pouch type flexible film battery according to a modified embodiment of the present invention.
3 is a cross-sectional view illustrating an exemplary pouch film according to embodiments of the present invention.
4 is a cross-sectional view illustrating an exemplary conductive carbon layer according to embodiments of the present invention.
5 is a cross-sectional view illustrating an exemplary anode layer according to some embodiments of the present invention.
6 is a cross-sectional view illustratively illustrating a cathode layer according to some embodiments of the present invention.
7 is a cross-sectional view illustrating an exemplary polymer electrolyte layer according to some embodiments of the present invention.
8 and 9 are flowcharts illustrating a method of manufacturing a pouch-type flexible film battery according to embodiments of the present invention.
FIGS. 10 and 11 are views illustrating a method of manufacturing a pouch type flexible film battery according to embodiments of the present invention.
FIG. 12 is a view showing an exemplary method of forming a polymer electrolyte layer according to an embodiment of the present invention.
13 to 15 are graphs illustrating some of the technical advantages of the pouch type flexible film secondary battery according to the embodiments of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects, features, and advantages of the present invention will become more readily apparent from the following description of preferred embodiments with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described herein but may be embodied in other forms. Rather, the embodiments disclosed herein are provided so that the disclosure can be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

In this specification, when it is mentioned that a film is on another film or substrate, it means that it may be formed directly on another film or substrate, or a third film may be interposed therebetween. Further, in the drawings, the thicknesses of the films and regions are exaggerated for an effective explanation of the technical content. Also, while the terms first, second, third, etc. in various embodiments of the present disclosure are used to describe various regions, films, etc., these regions and films should not be limited by these terms . These terms are only used to distinguish any given region or film from another region or film. Thus, the membrane referred to as the first membrane in one embodiment may be referred to as the second membrane in another embodiment. Each embodiment described and exemplified herein also includes its complementary embodiment.

1 is a perspective view exemplarily showing a pouch type flexible film battery according to some embodiments of the present invention. 2 is a perspective view exemplarily showing a pouch type flexible film battery according to a modified embodiment of the present invention.

1, a pouch type flexible film battery according to some embodiments of the present invention includes a cathode structure 100, an anode structure 200, and at least one polymer electrolyte layer 140, 240 interposed therebetween, . The cathode structure 100 includes a cathode conductive layer 120 and a cathode layer 130 which are sequentially stacked on a cathode pouch film 110 and the anode structure 200 is formed on the cathode pouch film 210 And may include a cathode conductive layer 220 and an anode layer 230 which are sequentially stacked.

The polymer electrolyte layers 140 and 240 may include a first polymer electrolyte layer 140 to which the cathode layer 130 is attached and a second polymer electrolyte layer 240 to which the anode layer 230 is attached . The first and second polymer electrolyte layers 140 and 240 may be bonded to each other to form one polymer electrolyte layer.

According to embodiments of the present invention, the cathode and anode pouch films 110 and 210 are fused to each other around the polymer electrolyte layers 140 and 240 so that the polymer electrolyte layers 140 and 240, And the anode conductive layer 120, 220, the cathode layer 130, and the anode layer 230 may be sealed. For this purpose, the cathode and anode pouch films 110 and 210 may be formed of a material capable of providing both a vacuum sealing property and a thermal fusion property, as will be described in more detail with reference to FIG.

Meanwhile, the pouch type flexible film battery according to the present invention has cathode and anode terminals connected to the cathode and anode conductive carbon layers 120 and 220, respectively. The cathode and anode terminals may be used as a path for supplying electric energy stored in the pouch type flexible film battery according to the present invention to an external electronic device. In some embodiments, the cathode and anode conductive carbon layers 120 and 220 may extend to function as the cathode and anode terminals. In this case, the cathode and anode terminals are formed of a non-metallic material (i.e., the cathode and anode conductive carbon layers 120 and 220). However, according to other embodiments, the cathode and anode terminals may be metallic materials, which are formed separately.

2, the sealing materials 50 for improving the vacuum sealing property are formed on the cathode and anode conductive carbon layers 120 and 220 and the cathode and anode pouch films 120 and 220. In other words, (110, 210). The encapsulant 50 may be formed to cross the negative and positive terminals. According to some embodiments, the encapsulant 50 may be a material (e.g., hotmelting films) that can be melted through a thermal process. As the hot melt film, polyethylene, amorphous polypropylene (c-PP), ethylene vinyl acetate (EVA) or ethylene vinyl alcohol (EVOH) may be used. However, according to other embodiments, since the cathode and anode pouch films 110 and 210 are formed of a material capable of providing both a vacuum sealing property and a heat welding property together as described above, , The cathode and anode terminals may be sealed directly by the cathode and anode pouch films 110 and 210 without the sealing material 50. [

3 to 7, the technical features related to the components constituting the cathode and anode structures 100 and 200 and the polymer electrolyte layer 300 will be described in more detail.

3 is a cross-sectional view illustrating an exemplary pouch film according to embodiments of the present invention.

The pouch film 10 to be described below with reference to FIG. 3 can be used as the cathode and anode pouch films 110 and 210. The pouch film 10 has both a vacuum sealing property and a heat sealing property. According to some embodiments, the pouch film 10 may comprise a plurality of membranes formed of a metal / polymer composite membrane or a polymer composite membrane. 3, the pouch film 10 may be a triple layer structure of an outer layer 11, an intermediate layer 12 and an inner layer 13, and the outer layer 11, the intermediate layer 12 ) And the inner layer (13) may be different materials.

More specifically, the outer layer 11 may be made of a material selected from the group consisting of polyethylene terephthalate, polybutylene terephthalate, nylon, HDPE, oriented polypropylene (o-PP), polyvinyl chloride, polyimide, polysulfone, A combination thereof, and the thickness thereof may be approximately 5 占 퐉 to approximately 50 占 퐉.

The intermediate layer 12 may be formed to a thickness of about 5 탆 to about 50 탆, and may include at least one of metallic materials or non-metallic materials. The metallic materials for the intermediate layer 12 may be, for example, aluminum, copper, stainless steel or their respective alloys, and the non-metallic materials for the intermediate layer 12 may be, for example, High density polyethylene, polyvinyl chloride, polyimide, Teflon, and blends thereof.

The inner layer 13 may be a polymer film formed to a thickness of about 5 탆 to about 50 탆. For example, the inner layer 13 may be formed of a polymeric film selected from the group consisting of amorphous polypropylene (c-PP), polyethylene, ethylene vinyl acetate (EVA), ethylene vinyl alcohol (EVOH) have.

On the other hand, since some of the materials exemplified for the inner layer 13 (e.g., polypropylene) have low surface energy and hydrophobic characteristics, the cathode or anode conductive carbon layer 120 It may be difficult to coat directly on the substrate 13. The difficulty in this coating process may be due to the fact that polypropylene does not have compatibility or miscibility with most polar polymeric materials used as binders in electrode slurries.

In addition to the difficulty in this coating, due to the low surface energy and hydrophobicity, the cathode or anode conductive carbon layer 120 or 220 can be easily peeled off from the pouch film 10 even after being coated. Such delamination creates a gap between the cathode or anode conductive carbon layer 120 or 220 and the pouch film 10 and thus may cause technical problems such as leakage or drying of the electrolyte, Can be induced. In particular, in the case of flexible devices, such exfoliation may occur more easily because there may be an external force by the user. For this reason, in the field of flexible battery technology, it is particularly required to prevent peeling between the cathode or anode conductive carbon layer (120 or 220) and the pouch film (10).

According to some embodiments of the present invention, the inner layer 13 may have a surface treated top surface and the cathode or anode conductive carbon layer 120 or 220 may be coated on the surface treated top surface have. The surface treatment can be carried out to solve difficulties and peeling problems in the coating described above. For example, the surface of the inner layer 13 may have hydrophilicity by the surface treatment. The surface treatment may be carried out through at least one of corona discharge treatment, plasma treatment, formation of a silicate film through flame treatment or formation of an oxide film through a coating process, but is not limited thereto, and other micro-roughness layer forming technology . ≪ / RTI > According to some embodiments, the surface treated top surface of the inner layer 13 may have a surface energy of at least 50 mN / m or greater under the test ink measurement method, by the surface treatment.

4 is a cross-sectional view illustrating an exemplary conductive carbon layer according to embodiments of the present invention. The conductive carbon layer 20 described with reference to FIG. 4 may be used as at least one of the cathode and anode conductive carbon layers 120 and 220. The pouch film 10 coated with the conductive carbon layer 20 may constitute a positive electrode or a negative electrode current collector in the pouch type flexible film battery according to the embodiments of the present invention.

Referring to FIG. 4, the conductive carbon layer 20 may include a conductive carbon and a polymer binder. The conductive carbon may be at least one of graphite, hard carbon, soft carbon, carbon fiber, carbon nanotube, carbon black, acetylene black or Ketjen black. Wherein the polymer binder is selected from the group consisting of polyvinylidene fluoride, a copolymer of vinylidene fluoride and hexafluoropropylene, a polyvinyl chloride, a cellulosic polymer, a polyethylene, a polypropylene, an ethylene vinyl acetate, a polyvinyl alcohol or a combination thereof Wherein the cellulose polymer is at least one of cellulose, methylcellulose, ethylcellulose, butylcellulose, hydroxypropylcellulose, cellulose nitrate, cellulose acetate, cellulose acetate propionate, cellulose acetate butyrate or carboxymethylcellulose have. According to some embodiments, the ratio of use between the conductive carbon and the polymeric binder may be from 8.5: 1 to 9.9: 0.1 by weight, but the technical idea of the present invention is not limited to these exemplified numerical ranges.

Meanwhile, according to some embodiments of the present invention, the thickness of the pouch film 10 or the cathode or anode pouch film 110 or 210 may be approximately 50 μm to approximately 180 μm, and the conductive carbon layer 20 Or the thickness of the cathode or anode conductive carbon layer 120 or 220 may be approximately 1 [mu] m to approximately 30 [mu] m.

5 is a cross-sectional view illustrating an exemplary anode layer according to some embodiments of the present invention.

Referring to FIG. 5, the anode layer 230 is coated on the anode conductive carbon layer 220 as shown in FIGS. 1 and 2, and may include a cathode active material, a conductive material, and a binder.

The cathode active material may be one of lithium oxides, their mixtures or solid solutions. According to some embodiments, the lithium oxide for the cathode active material is selected from the group consisting of nanosize olivine (LiFePO ₄ ), lithium cobalt oxide (LiCoO ₂ ), lithium nickel oxide (LiNiO ₂ ) or lithium manganese oxide ₂ O ₄ ). The lithium oxides other than the olivine may be formed to have a particle size of about 1 [mu] m to about 100 [mu] m. Meanwhile, according to the modified embodiments, the cathode active material may be provided as a solid solution of lithium compounds to which a metal element such as aluminum, iron, copper, titanium, or magnesium is added.

The conductive material may be at least one of graphite, hard carbon, soft carbon, carbon fiber, carbon nanotube, carbon black, acetylene black, Ketjenblack, Lonza carbon or combinations thereof. The binder may be selected from the group consisting of polyvinylidene fluoride, a copolymer of vinylidene fluoride and hexafluoropropylene, a polyvinyl chloride, a cellulose-based polymer, polyethylene, polypropylene, ethylene vinyl acetate, polyvinyl alcohol, styrene / butadiene rubber / carboxy Methyl cellulose mixture or a combination thereof, wherein the cellulose-based polymer is selected from the group consisting of cellulose, methylcellulose, ethylcellulose, butylcellulose, hydroxypropylcellulose, cellulose nitrate, cellulose acetate, cellulose acetate propionate, cellulose Acetate butyrate, or carboxymethylcellulose.

The weight ratio of the cathode active material, the conductive material and the binder constituting the anode layer 230 may be about 8: 1: 1 to about 9.8: 0.1: 0.1, and the anode layer 230 may have a weight ratio of about 30 To about 150 mu m. However, the technical spirit of the present invention is not limited to the weight ratio or thickness exemplified here, and can be variously modified.

6 is a cross-sectional view illustratively illustrating a cathode layer according to some embodiments of the present invention.

Referring to FIG. 6, according to some embodiments, the cathode layer 130 may be provided in the form of a lithium foil. In this case, the cathode layer 130 may be adhered to the anode conductive carbon layer 120 through a compressing process or the like.

According to other embodiments, the cathode layer 130 may include a carbon-based or non-carbon-based material coated on the cathode conductive carbon layer 120. For example, the cathode layer 130 may include a carbon-based or non-carbon-based anode active material, a conductive material, and a binder. The carbon-based anode active material may include at least one of graphite, hard carbon, or soft carbon, and the non-carbon based negative active material may include at least one of tin, silicon, or lithium titanium oxide. In addition, the lithium titanium oxide for the non-carbon anode active material may be lithium titanium oxide (Li _x TiO ₂ ) nanotubes or spinel lithium titanium oxide (Li ₄ Ti ₅ O ₁₂ ) coated with carbon particles.

The conductive material and the binder for the cathode layer 130 each include at least one of those exemplified as the material for the conductive material and the binder for the anode layer 230 described with reference to Figure 5 . That is, the conductive material for the cathode layer 130 may be at least one of graphite, hard carbon, soft carbon, carbon fiber, carbon nanotube, carbon black, acetylene black, Ketjenblack, The binder for the negative electrode layer 130 may be selected from the group consisting of polyvinylidene fluoride, a copolymer of vinylidene fluoride and hexafluoropropylene, a polyvinyl chloride, a cellulosic polymer, polyethylene, polypropylene, ethylene vinyl acetate, polyvinyl alcohol , A styrene / butadiene rubber / carboxymethyl cellulose mixture, or a combination thereof, wherein the cellulose-based polymer is selected from the group consisting of cellulose, methyl cellulose, ethyl cellulose, butyl cellulose, hydroxypropyl cellulose, cellulose nitrate, cellulose acetate, Cellulose acetate propione At least one agent, cellulose acetate butyrate, or carboxymethyl cellulose may be. The weight ratio of the negative electrode active material, the conductive material, and the binder constituting the negative electrode layer 130 may be about 8: 1: 1 to about 9.8: 0.1: 0.1.

On the other hand, the cathode layer 130 may be formed to a thickness of about 15 탆 to about 150 탆. According to some embodiments, the thickness of the cathode layer 130 may be half the thickness of the anode layer 230.

7 is a cross-sectional view illustrating an exemplary polymer electrolyte layer according to some embodiments of the present invention.

Referring to FIG. 7, the polymer electrolyte layer 40 may be a gel-type polymer electrolyte having adhesive properties. According to some embodiments, the gel-type polymer electrolyte may be a polymer material mixed with a lithium salt, a cellulose-based polymer, and a strength-strengthening polymer. In addition, the polymer electrolyte layer 40 may be formed to have a thickness of about 5 탆 to about 150 탆.

According to some embodiments, the lithium salt for the polymer electrolyte layer 40 is selected from the group consisting of lithium perchlorate (LiClO ₄ ), lithium triflate (LiCF ₃ SO ₃ ), lithium hexafluorophosphate (LiPF ₆ ), lithium tetrafluoro Borate (LiBF ₄ ), lithium trifluoromethanesulfonylimide (LiN (CF ₃ SO ₂ ) ₂ ), or combinations thereof.

According to one aspect of the present invention, the polymer electrolyte layer 40 may have the above-described adhesion property by the cellulose-based polymer, and may have improved mechanical strength and improved molding properties by the strength reinforcing polymer. The weight ratio of the cellulose-based polymer to the strength-enhancing polymer may be 1: 999 to 999: 1. According to some embodiments, the weight ratio may be from 1:99 to 99: 1.

According to some embodiments, the cellulosic polymer is selected from the group consisting of cellulose, methyl cellulose, ethyl cellulose, butyl cellulose, hydroxypropyl cellulose, cellulose nitrate at least one of cellulose nitrate, cellulose acetate, cellulose acetate propionate, cellulose acetate butyrate, or carboxymethyl cellulose.

According to some embodiments, the strength-enhancing polymer may be a polyvinylidene fluoride-based polymer. For example, the strength-enhancing polymer can be selected from the group consisting of polyvinylidene fluoride, a copolymer of vinylidene fluoride and co-hexa fluoropropylene (VIN), vinylidene fluoride and trifluoro (Vinylidene fluoride-co-trifluoroethylene), a copolymer of vinylidene fluoride and polytetrafluoroethylene (polyvinylidene fluoride-co-tetrafluoroethylene).

However, according to other embodiments, the strength-enhancing polymer may be a polyvinylchloride derivative, an acrylonitrile polymer derivative, a polyvinylacetate, a polyvinylalcohol, a polyimide, a poly Polysulfone or polyurethane may be used. The acrylonitrile-based polymer derivative may be at least one of a copolymer of acrylonitrile and methyl methacrylate or polyacrylonitrile. The acrylate-based polymer may be at least one selected from the group consisting of polymethylmethacrylate, At least one of polyethylacrylate, polyethylmethacrylate, polybutylacrylate or polybutylmethacrylate may be used.

Meanwhile, the polymer electrolyte layer 40 may further include an inorganic additive. For example, the polymer material is added with at least one as the inorganic additive in the polymer electrolyte layer 40 is of silica, talc, alumina (Al ₂ O _3), TiO _2, clay (Clay), zeolites or combinations thereof Lt; / RTI >

FIGS. 8 and 9 are flow charts illustrating a method of manufacturing a pouch-type flexible film battery according to embodiments of the present invention, and FIGS. 10 and 11 illustrate a pouch type flexible film according to embodiments of the present invention Which are illustrations of a method of manufacturing a battery. For the sake of brevity of description, the technical features relating to the materials and the like of the components already described with reference to Figs. 1 to 7 can be omitted from the following description.

8 to 11, the manufacturing method includes independently forming a first structure including a negative electrode collector of a film battery and a second structure including a positive electrode collector of the film battery (S10, S20) And bonding them (S30). In addition, the manufacturing method may further include a separating step (S40) of separating each of the film cells by cutting the bonded first and second structures.

The forming of the first structure (S10) includes a step (S11) of surface-treating one surface of the first film, a step (S12) of forming a first carbon layer on the surface-treated surface of the first film, Forming a first electrode layer on the first carbon layer (S14), and forming a first electrolyte layer on the first electrode layer (S17).

Similarly, the step S20 of forming the second structure may include a step S21 of surface-treating one surface of the second film, a step of forming a second carbon layer on the surface-treated surface of the second film S22), and forming a second electrode layer on the second carbon layer (S24). According to some embodiments, forming (S20) the second structure may further comprise forming (S27) a second electrolyte layer on the second electrode layer as shown in Figures 8 and 10 have. However, according to other embodiments, the step of forming one of the first and second electrolyte layers may be omitted. For example, as shown in FIGS. 9 and 11, in the step of forming the second structure (S20), the step S27 of forming the second electrolyte layer on the second electrode layer may be omitted.

According to some embodiments, the first and second films may be the pouch film 10 described with reference to FIG. 3, and the first and second carbon layers may be formed from the conductive Carbon layer 20, and the first and second electrode layers may be the negative electrode layer 130 and the positive electrode layer 230 described with reference to FIGS. 6 and 5, respectively. In addition, the first and second electrolyte layers may be the polymer electrolyte layer 40 described with reference to FIG.

(S11, S21) of surface treatment of the first and second films may be performed so that the surface on which the first and second carbon layers are formed has hydrophilicity. For example, the surface treatment step (S11, S21) may be carried out through at least one of corona discharge treatment, plasma treatment, silicate film formation through flame treatment, or oxide film formation through a coating process. However, the method of the surface treatment step (S11, S21) is not limited to these illustrated methods and may be carried out through other micro-roughness layer forming techniques.

According to some embodiments, the first and second films may comprise a lead-free polypropylene film, and the surface treatment step (S11, S21) may be performed on the lead-free polypropylene film. In this case, according to the experiment of the inventors, the unleaded polypropylene film surface-treated using the corona discharge method could have a surface energy of 60 mN / m or more under the test ink measuring method. According to embodiments of the present invention, the surface treatment step (S11, S21) may be performed so that the surface energy of the film has at least 50 mN / m. By the surface treatment step (S11, S21), the first and second carbon layers can be easily coated on the first and second films, and the peeling problem between the carbon layers and the pouch film Can also be mitigated.

The first and second carbon layers, the first and second electrode layers, and the first and second electrolyte layers may be formed using a screen printing technique. By the use of the screen printing technique, they can be locally formed in predetermined areas of the first or second films. On the other hand, the screen printing technique has been exemplified in an economical way in which the first and second carbon layers, the first and second electrode layers, and the first and second electrolyte layers can locally be formed . That is, the technical idea of the present invention is not limited to the use of the screen printing technology, but can be implemented using various other pattern forming methods.

The step (S30) of bonding the first and second structures (hereinafter referred to as an adhering step) may be performed such that the first and second electrolyte layers face each other. That is, the adhesion step S30 may be performed such that the first and second electrolyte layers are sandwiched between the first and second films. On the other hand, in the embodiments described with reference to FIGS. 9 and 11, since the second electrolyte layer is omitted, the first and second electrode layers can be respectively adhered to two opposing surfaces of the first electrolyte layer have.

According to some embodiments, the adhering step S30 may be conducted under a pressure condition lower than normal pressure. However, according to other embodiments, the adhering step S30 may be carried out under substantially atmospheric conditions. On the other hand, the depressurization condition not only requires an additional vacuum facility but also causes a delay in the process time for depressurization. Accordingly, a manufacturing method requiring a reduced pressure method may be incompatible with a roll-to-roll system. On the other hand, in the case of the embodiments carried out under the above atmospheric pressure condition, since the delay time in the process time for the reduced pressure does not occur, it is easy to apply in the roll-to-roll system.

According to some embodiments, as shown in Figs. 10 and 11, the adhering step S30 may be performed in a rolling manner using a pair of rollers. In addition, the bonding step S30 may be performed under a temperature condition (for example, 100 degrees centigrade or more) capable of fusing the inner layers 13 of the pouch film 10 to each other. That is, the pouch films 10 can be sealed using a heat fusion method.

Meanwhile, as described with reference to FIG. 7, the first and second electrolyte layers may be gel polymer electrolytes having adhesive properties. Since such an adhesive gel polyelectrolyte is used, the adhering step (S30) can be carried out under an atmospheric pressure condition. That is, when the electrolyte is injected into the pouch as a liquid phase, the rolling method as in FIGS. 10 and 11 can not be used in the adhesion step S30. In addition, when the rolling method can not be used, it is required to perform the adhesion step (S30) by using a separate decompression facility in order to remove the air inside the pouch.

Meanwhile, according to one aspect of the present invention, a pouch-type flexible film battery can be manufactured using a roll-to-roll system. For example, the roll-to-roll system may be configured to successively perform the steps of forming the first and second structures (S10, S20) and adhering them (S30). That is, the method of manufacturing the above-mentioned film battery may be implemented through a reel-to-reel process.

More specifically, as shown in Figs. 10 and 11, the first and second films are transferred from the different reels through the roll-to-roll system to the adhesion step S30 and the battery separation step S40 The equipment is supplied continuously. In this case, the first and second structures are formed on the first and second films through facilities disposed between the rolls and the equipment for the bonding step (S30). According to some embodiments, the first and second carbon layers, the first and second electrode layers, and the first and second electrolyte layers are formed using a screen printing facility, As shown in FIG. Such roll-to-roll system and screen printing equipment can enable automation, serialization and mass production in the manufacturing process, and as a result, the manufacturing cost of the film battery can be lowered.

On the other hand, according to some embodiments, as shown in Figs. 10 and 11, the first and second carbon layers, the first and second electrode layers, and the first and second electrolyte layers (S13, S15, S18, S23, S25, and S28) for drying the coated films may be further performed. In addition, according to some embodiments, steps of rolling the coated film using certain rollers may be further implemented. For example, as shown in Figs. 10 and 11, this rolling step may be performed after forming the first and second electrode layers (S15, S25).

FIG. 12 is a view showing an exemplary method of forming a polymer electrolyte layer according to an embodiment of the present invention.

Referring to FIG. 12, the method includes steps of preparing a cellulose-based polymer and a strength-enhancing polymer (S51), dissolving the same in a co-solvent (S52), adding a liquid electrolyte to the resultant and stirring . As a result, an electrolyte solution can be prepared. Thereafter, step (S17) of coating the electrolyte solution on the first or second film and step (S18) of drying the resultant are further performed. As described above, the step of coating the electrolyte solution can be performed using a screen printing technique. The co-solvent is volatilized during the drying step (S18), so that the coated electrolyte solution remains as a gel polymer electrolyte on the first or second film.

  According to some embodiments, the cellulosic polymer is selected from the group consisting of cellulose, methyl cellulose, ethyl cellulose, butyl cellulose, hydroxypropyl cellulose, cellulose nitrate at least one of cellulose nitrate, cellulose acetate, cellulose acetate propionate, cellulose acetate butyrate, or carboxymethyl cellulose.

The strength reinforcing polymer may be selected from the group consisting of polyvinylidene fluoride polymers, polyvinylchloride derivatives, acrylonitrile polymer derivatives, polyvinylacetate, polyvinylalcohol, polyimide, And may be at least one of polysulfone or polyurethane. The polyvinylidene fluoride-based polymer may be at least one selected from the group consisting of polyvinylidene fluoride, a copolymer of vinylidene fluoride-co-hexa fluoropropylene (VDI) and hexafluoropropylene, (Vinylidene fluoride-co-trifluoroethylene), a copolymer of vinylidene fluoride and co-tetrafluoroethylene (Poly (vinylidene fluoride-co-tetrafluoroethylene) The nitrile-based polymer derivative may be at least one of a copolymer of acrylonitrile and methyl methacrylate or polyacrylonitrile. The acrylate-based polymer may be at least one selected from the group consisting of polymethylmethacrylate, polyethylacrylate, , Polyethylmethacrylate (Polyethylmethacrylate), polybutyl acrylate acrylate or polybutylmethacrylate. < / RTI >

According to some embodiments, the co-solvent is selected from the group consisting of N-methylpyrrolidone (NMP), D-methylformamide (DMF), D-methylformacetate (DMAc), acetone, ethanol, methanol, propanol, Ethylene glycol monobutyl ether, diethylene glycol diethyl ether, diethylene glycol butyl vinyl ether, diethylene glycol monododecyl ether, diethylene glycol monohexadecyl ether, diethylene glycol monohexyl ether, diethylene glycol monooctyl ether, Diethylene glycol mono-octadecyl ether, diethylene glycol monophenyl ether, diethylene glycol monopropyl ether, or combinations thereof. According to other embodiments, the co-solvent is selected from the group consisting of ethylene carbonate, propylene carbonate, dibutyl carbonate, diethyl carbonate, ethyl methyl carbonate, tetrahydrofuran, 2-methyltetrahydrofuran, dimethoxyethane, Formate, gamma-butyrolactone, or combinations thereof.

According to some embodiments, the liquid electrolyte may comprise a lithium salt. More specifically, the lithium salt for the liquid electrolyte is selected from the group consisting of lithium perchlorate (LiClO ₄ ), lithium triflate (LiCF ₃ SO ₃ ), lithium hexafluorophosphate (LiPF ₆ ), lithium tetrafluoroborate (LiBF ₄ ) trifluoroacetate may be methane sulfonyl imide _{(LiN (CF 3 SO 2)} 2) or a at least one of the combinations thereof.

According to some embodiments, the step of adding the inorganic additive may be further performed to improve the mechanical strength of the polymer electrolyte layer 40 and / or to improve the impregnation and retention characteristics of the liquid electrolyte. Step (S53) may be carried out after dissolving step (S52) of using the co-solvent, wherein the inorganic additive is silica, talc, alumina (Al ₂ O _3), titanium oxide is added to the inorganic additive (TiO ₂ ), Clay, zeolite, or combinations thereof.

The polymer electrolyte layer (40) according to the present invention has excellent adhesion properties by including a cellulose-based polymer. As a result, excellent adhesion properties can be maintained even on the surface of the rough and uneven inorganic layer as in the electrode. In addition, since the cellulosic polymer is an electrochemically very stable material, it is not easily decomposed by an applied voltage and is also excellent in resistance to attacks by radicals or electrons. According to some embodiments, the cellulosic polymer may be used in combination with PVdF or PVdF derivative polymers. According to these embodiments, the electrochemical stability can be further improved.

On the other hand, since the polymer electrolyte layer 40 provides excellent ion conduction characteristics, the electrical characteristics of the film battery according to the present invention can be improved. Although the viscosity of the polymer medium is rapidly increased by the cellulose-based polymer, unlike the general expectation, according to the experiment of the inventors, the polymer electrolyte layer 40 has excellent ion conduction at 10 ^-3 S / cm or more at room temperature It was confirmed that the characteristics can be maintained.

In addition, as described above, although the electrolyte solution is directly coated on the surface of the electrode layer, the co-solvent contained therein may dissolve or swell the electrode layer even after coating the electrolyte solution or even in the drying step ).

  13 to 15 are graphs illustrating some of the technical advantages of the pouch type flexible film secondary battery according to the embodiments of the present invention.

The inventors made the samples to be referred to as Experimental Examples 1 and 2 and the samples to be referred to as Comparative Examples 1 and 2, and the respective curves of the graphs show the measured results from these samples. The curves denoted by reference numerals E1 and E2 represent the results measured from the samples (i.e., Experiments 1 and 2) prepared on the basis of the technical idea of the present invention described above, and reference numerals C1 and C2 Are the results measured from the samples prepared for comparison with the present invention (i.e., Comparative Examples 1 and 2).

Samples for Experiments 1 and 2 and Comparative Examples 1 and 2 were prepared as follows.

[ Experimental Example  1: 4V class pouch type Flexible  Film secondary battery]

As the inner layer, the intermediate layer and the outer layer of the pouch film, unleaded polypropylene having a thickness of 35 mu m, aluminum foil having a thickness of 30 mu m and nylon having a thickness of 15 mu m were used. Through the lamination process, the pouch film was prepared to have a thickness of 75 mu m. The inner layer was surface-treated under an atmospheric environment using a corona discharger so that the inner layer had hydrophilicity. Specifically, the surface treatment was carried out so that the inner layer had a surface energy of 50 mN / m.

Thereafter, a high-viscosity carbon paste was coated on the inner layer using a screen printer to form a cathode conductive carbon layer constituting the cathode current collector. The carbon paste was prepared by dissolving 5% by weight of ethyl cellulose in NMP (N-methyl pyrrolidone), adding 90% by weight of graphite and 5% by weight of carbon black. Subsequently, according to the measurement after the drying step, the thickness of the cathode conductive carbon layer was 20 μm and the area was 4.3 cm × 4.3 cm.

A positive electrode layer having a thickness of 100 mu m was formed on the positive electrode conductive carbon layer. The anode layer was formed through a method of coating an oxide paste using a screen printer. The oxide paste was prepared by preparing an NMP solution containing 5% by weight of polyvinylidene fluoride, and then mixing the cathode active material, the conductive material and the binder in the solution. 90 wt% of lithium cobalt oxide (LiCoO ₂ ), 5 wt% of graphite, and 5 wt% of polyvinylidene fluoride were used as the positive electrode active material, the conductive material and the binder, respectively.

A negative electrode current collector was prepared by forming a negative electrode conductive carbon layer on the inner layer of the pouch film. The negative electrode collector was prepared in the same manner as the positive electrode collector. Thereafter, a cathode layer of 50 mu m was formed on the cathode conductive carbon layer. The paste for the negative electrode layer was prepared by preparing an NMP solution containing 5 wt% of polyvinylidene fluoride, adding 95 wt% of natural graphite as an anode active material and 5 wt% of polyvinylidene fluoride as a binder Ready.

Gel polymer electrolytes having adhesive properties were formed on the anode layer and the cathode layer by a screen printing method. More specifically, a high-viscosity solution containing an electrolyte was prepared, coated on the anode layer and the cathode layer by a screen printing method, and the solution was dried to complete the gel polymer electrolyte. The high viscosity solution was prepared by preparing an NMP solution containing 30% by weight of ethyl cellulose, dissolving a copolymer of vinylidene fluoride and hexafluoropropylene therein in an amount of 70% by weight, adding 15% by weight of the blended polymer matrix By weight of hydrophobic silica, and then adding a liquid electrolyte so as to be 300% by weight based on the blended polymer matrix. Then, the pouch films were arranged so that the gel polymer electrolytes were facing each other, and then they were thermally fused.

[ Experimental Example  2: 3V class pouch type Flexible  Film secondary battery]

The film battery according to Experimental Example 2 was produced in the same manner as the film battery of Experimental Example 1 except that olivine (LiFePO ₄ ) nanoparticles coated with carbon particles were used as a cathode active material.

[ Comparative Example  One]

The film battery according to Comparative Example 1 was fabricated in a structure similar to that of the film battery according to Experimental Example 1, except for the differences to be described below. The positive and negative current collectors were formed of copper and aluminum respectively, and the anode layer and the cathode layer were formed of lithium cobalt oxide and natural graphite, respectively, and nickel and aluminum taps were used as terminals for electrical connection to the anode and the cathode, respectively . In the case of the electrolyte, vinylidene fluoride and hexafluoropropylene copolymer were used as the polymer matrix. However, unlike in Experimental Example 1, the electrolyte of the sample of Comparative Example 1 contained no cellulose-based polymer.

[ Comparative Example  2]

The film battery according to Comparative Example 2 was produced in the same manner as the film battery of Comparative Example 1 except that olivine (LiFePO ₄ ) nanoparticles coated with carbon particles were used as a cathode active material.

13, the horizontal axis and the vertical axis represent the discharge capacity and the voltage of the sample, respectively. That is, FIG. 13 shows a change in voltage depending on the discharge capacity of the samples.

Referring to FIG. 13, when the sizes and thicknesses of the samples are the same, Experiments 1 and 2 (E1 and E2) had better discharge capacity characteristics than Comparative Examples 1 and 2 (C1 and C2). For example, in Experimental Example 1, the discharge capacity value was about 1.5 times or more larger than that of Comparative Example 1.

Figs. 14 and 15 show the results of measuring the impedance of the sample to examine the contact characteristics between the electrode and the electrolyte. Fig.

14 and 15, Experiments 1 and 2 (E1 and E2) had lower resistance values than Comparative Examples 1 and 2 (C1 and C2), respectively. That is, as shown in Figure 14, the resistance value (Z in Experimental Example 1, _E1) is the resistance value (Z in Comparative Example 1, was lower than _C1), 15 a, as, the resistance of the experimental example 2 shown in (Z ' _E2 ) was lower than the resistance value (Z' _C2 ) of Comparative Example 2. From these experimental results, it can be confirmed that the film battery according to the present invention has better contact properties than the film batteries of Comparative Examples 1 and 2.

Meanwhile, the film battery according to the present invention may be provided as a primary battery or a secondary battery, and the magnitude of an output voltage to be implemented may vary. Further, as described above, since the constituent elements constituting the film battery are composed of flexible materials, the film battery according to the present invention can have a flexible characteristic. Accordingly, in the film battery according to the present invention, the battery can be used as a power supply device for various flexible devices such as rolled-up display, e-paper, flexible LCD, flexible OLED, However, it is apparent that the electronic products in which the film battery according to the present invention can be used are not limited to those exemplified herein.

Claims (20)

A positive electrode structure comprising a positive electrode pouch, a positive electrode conductive carbon layer and an anode layer;
A negative electrode structure including a negative electrode pouch, a negative electrode conductive carbon layer, and a negative electrode layer; And
And a polymer electrolyte layer between the anode and the cathode structure,
Wherein the anode and the cathode pouches are surface treated to have hydrophilic inner layer; Outer layer; And an intermediate layer interposed between the inner layer and the outer layer; / RTI >
Wherein the intermediate layer is a mixture of a metal and a polymer film, and the polymer film is at least one of polyester, high density polyethylene, polyvinyl chloride, polyimide, Teflon, and blends thereof,
Wherein the polymer electrolyte layer is a gel electrolyte including a cellulose-based polymer and a strength-enhancing polymer,
The cellulosic polymer may be selected from the group consisting of methyl cellulose, ethyl cellulose, butyl cellulose, hydroxypropyl cellulose, cellulose nitrate, cellulose acetate, A cellulose acetate propionate, or cellulose acetate butyrate, which is at least one of cellulose acetate propionate and cellulose acetate butyrate. The method according to claim 1,
Wherein the weight ratio of the cellulose-based polymer to the strength-enhancing polymer is 1:99 to 99: 1. delete The method according to claim 1,
The strength reinforcing polymer may be at least one selected from the group consisting of a polyvinylidene fluoride polymer, a polyvinylchloride derivative, an acrylonitrile polymer derivative, an acrylate polymer, a polyvinylacetate, a polyvinyl alcohol, a polyimide At least one of polyimide, polysulfone or polyurethane,
The polyvinylidene fluoride-based polymer may be at least one selected from the group consisting of polyvinylidene fluoride, a copolymer of vinylidene fluoride-co-hexa fluoropropylene (VDI) and hexafluoropropylene, (Vinylidene fluoride-co-trifluoroethylene), a copolymer of vinylidene fluoride and co-tetrafluoroethylene (polyvinylidene fluoride-co-tetrafluoroethylene)
Wherein the acrylonitrile-based polymer derivative comprises at least one of a copolymer of acrylonitrile and methyl methacrylate or polyacrylonitrile,
The acrylate-based polymer may be at least one selected from the group consisting of polymethylmethacrylate, polyethylacrylate, polyethylmetahcrylate, polybutylacrylate, and polybutylmethacrylate. A pouch type flexible film battery comprising: The method according to claim 1,
Wherein the gel electrolyte comprises a lithium salt,
The lithium salt may be at least one selected from the group consisting of lithium perchlorate (LiClO ₄ ), lithium triflate (LiCF ₃ SO ₃ ), lithium hexafluorophosphate (LiPF ₆ ), lithium tetrafluoroborate (LiBF ₄ ), lithium trifluoromethanesulfonylimide _{(LiN (CF 3 SO 2)} 2) or at least one of a flexible film pouch-shaped battery of the combinations thereof. The method according to claim 1,
Wherein the anode conductive carbon layer or the cathode conductive carbon layer is coated on the surface-treated surface of the inner layer. delete The method according to claim 1,
Wherein the inner layer is formed of at least one of amorphous polypropylene (c-PP), polyethylene, ethylene vinyl acetate (EVA), ethylene vinyl alcohol (EVOH), or a combination thereof. The method according to claim 1,
Wherein the positive electrode pouch and the negative electrode pouch are thermally welded to each other and are in direct contact with each other. Surface treating the inner surfaces of the first and second films so that inner surfaces of the first and second films have hydrophilicity;
Forming a positive electrode structure including a positive electrode conductive layer and a positive electrode layer sequentially formed on a first film;
Forming a negative electrode structure including a negative electrode conductive layer and a negative electrode conductive layer sequentially formed on a second film;
Forming a gel-type electrolyte layer including a cellulose-based polymer and a strength-enhancing polymer on at least one of the anode and cathode structures; And
And bonding the anode and cathode structures,
The step of bonding the positive electrode and the negative electrode structures may include bonding the first and second films to each other using the gel-like electrolyte layer as an adhesive layer using the heat fusion technique to adhere the positive electrode layer and the negative electrode layer to the gel- ≪ / RTI >
The cellulosic polymer may be selected from the group consisting of methyl cellulose, ethyl cellulose, butyl cellulose, hydroxypropyl cellulose, cellulose nitrate, cellulose acetate, At least one of cellulose acetate propionate, cellulose acetate butyrate, cellulose acetate propionate,
Wherein the first film and the second film are surface treated to have an inner layer having hydrophilicity; Outer layer; And an intermediate layer interposed between the inner layer and the outer layer,
Wherein the intermediate layer is a mixture of a metal and a polymer film, and the polymer film is at least one of polyester, high-density polyethylene, polyvinyl chloride, polyimide, Teflon, and blends thereof. The method of claim 10,
The manufacturing method is performed using a roll-to-roll system,
Wherein the roll-to-roll system is configured to continuously perform the step of forming the anode and cathode structures, the step of forming the gel-like electrolyte, and the step of adhering the anode and cathode structures. The method of claim 10,
Wherein the cathode conductive layer, the anode layer, the cathode conductive layer, and the cathode layer are formed using a screen printing technique. The method of claim 10,
The step of forming the gel-like electrolyte layer
Preparing an electrolyte solution comprising a polymer matrix dissolved in a co-solvent and a liquid electrolyte;
Coating the electrolyte solution on at least one of the anode and cathode structures; And
And drying the cosolvent,
The polymer matrix includes a cellulose-based polymer and a strength-enhancing polymer,
Wherein the liquid electrolyte comprises a lithium salt. delete The method of claim 10,
The strength reinforcing polymer may be at least one selected from the group consisting of a polyvinylidene fluoride polymer, a polyvinylchloride derivative, an acrylonitrile polymer derivative, an acrylate polymer, a polyvinylacetate, a polyvinyl alcohol, a polyimide At least one of polyimide, polysulfone or polyurethane,
The polyvinylidene fluoride-based polymer may be at least one selected from the group consisting of polyvinylidene fluoride, a copolymer of vinylidene fluoride-co-hexa fluoropropylene (VDI) and hexafluoropropylene, (Vinylidene fluoride-co-trifluoroethylene), a copolymer of vinylidene fluoride and co-tetrafluoroethylene (polyvinylidene fluoride-co-tetrafluoroethylene)
Wherein the acrylonitrile-based polymer derivative comprises at least one of a copolymer of acrylonitrile and methyl methacrylate or polyacrylonitrile,
The acrylate-based polymer may be at least one selected from the group consisting of polymethylmethacrylate, polyethylacrylate, polyethylmetahcrylate, polybutylacrylate, and polybutylmethacrylate. Wherein the pouch type flexible film battery comprises a pouch type flexible film battery. 14. The method of claim 13,
The co-solvent is selected from the group consisting of N-methylpyrrolidone (NMP), D-methylformamide (DMF), D-methylformacetate (DMAc), acetone, ethanol, methanol, propanol, ethylene glycol, diethylene glycol monobutyl ether Ethylene glycol diethyl ether, diethylene glycol butyl vinyl ether, diethylene glycol monododecyl ether, diethylene glycol monohexadecyl ether, diethylene glycol monohexyl ether, diethylene glycol monooctyl ether, diethylene glycol monooctadecyl ether , Diethylene glycol monophenyl ether, diethylene glycol monopropyl ether, or a combination thereof. delete The method of claim 10,
Wherein the gel electrolyte layer comprises a first electrolyte layer formed on the anode structure and a second electrolyte layer formed on the cathode structure,
Wherein the step of bonding the positive and negative electrode structures comprises adhering the first and second electrolyte layers to each other. The method of claim 10,
Wherein the step of forming the positive electrode conductive layer, the positive electrode layer, the negative electrode conductive layer, the negative electrode layer and the gel electrolyte layer, and adhering the positive electrode and negative electrode structures are carried out under a pressure- (Method for manufacturing flexible film battery). The method of claim 10,
Wherein the step of bonding the anode and cathode structures comprises sealing the inner space in which the electrolyte layer is disposed by fusing the first and second films around the electrolyte layer,
Wherein the electrolyte layer is formed in the inner space before the sealing step.

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