KR102442166B1 - Pouch for flexible secondary battery, flexible secondary battery having the same, and method of producing pouch for flexible secondary battery - Google Patents

Abstract

A heat-shrinkable tubular substrate extending in a longitudinal direction, wherein the heat-shrinkable tube has a first polymer resin region and a second polymer resin region having different heat shrinkage rates, and wherein the first polymer resin region and the second polymer resin region are heat-shrinkable. heat-shrinkable tubular substrates alternately disposed with each other in the longitudinal direction of the sex tubular substrates; an inorganic material layer formed on the outer surface of the heat-shrinkable tubular substrate; and a pouch for a flexible battery formed on the outer surface of the inorganic material layer and having a polymer resin layer made of a third polymer resin, and a flexible battery having the same.

Description

A pouch for a flexible secondary battery, a flexible secondary battery having the same, and a method for manufacturing a pouch for a flexible secondary battery

The present invention relates to a pouch for a flexible secondary battery, a flexible secondary battery having the same, and a method for manufacturing a pouch for a flexible secondary battery, and more particularly, to a pouch for a flexible secondary battery having improved flexibility when bending, a flexible secondary battery having the same, And it relates to a method of manufacturing a pouch for a flexible secondary battery.

A secondary battery refers to a device that converts external electrical energy into chemical energy, stores it, and generates electricity when needed. The term "rechargeable battery" is also used to mean that it can be recharged multiple times. Commonly used secondary batteries include lead storage batteries, nickel cadmium batteries (NiCd), nickel hydrogen storage batteries (NiMH), lithium ion batteries (Li-ion), and lithium ion polymer batteries (Li-ion polymer). A secondary battery provides both economical and environmental advantages over a primary battery that is used and discarded once.

In general, secondary batteries are manufactured by mounting an electrode assembly composed of a negative electrode, a positive electrode, and a separator inside a cylindrical or prismatic metal can or a pouch-type case of an aluminum laminate sheet, and injecting electrolyte into the electrode assembly. , prismatic or pouch-type batteries are most common.

Since a certain space for mounting the secondary battery is essential, the cylindrical, prismatic, or pouch-shaped secondary battery has a problem in that it acts as a constraint on the development of various types of portable devices. Accordingly, there is a demand for a secondary battery of a novel shape that is easily deformable.

In response to this demand, development of a secondary battery that can be easily deformed in various forms has been attempted, and as an example, a flexible secondary battery, which is a battery having a very large ratio of length to diameter of cross-sectional area, has been proposed. A pouch for protecting such a flexible secondary battery is required to have both flexibility and moisture barrier properties.

Referring to FIG. 1 , the conventional tubular pouch 10 of a flexible secondary battery includes a flat sheet-like substrate stacked in this order of a polymer resin layer 11 , a metal foil layer 12 , and a mechanical support layer 13 at both ends. The inner layer was bonded to form a tubular shape. As a result, as shown in FIG. 2, when a compressive force such as bending is applied to the pouch, bucking occurs on one side of the pouch, which in turn develops into cracks, which inevitably causes the surface of the metal foil layer to be bent or wrinkled. , and eventually, a problem such as tearing of the metal foil layer occurred.

Therefore, the problem to be solved by the present invention is to solve the above-mentioned problems, and to maximize the flexibility of the flexible secondary battery, even when a compressive force such as bending is applied, it can be flexibly deformed without the formation of cracks, a pouch for a flexible secondary battery, An object of the present invention is to provide a flexible secondary battery having the same, and a method for manufacturing a pouch for a flexible secondary battery.

In order to solve the problem of the present invention, according to one aspect of the present invention,

A heat-shrinkable tubular substrate extending in a longitudinal direction, wherein the heat-shrinkable tube has a first polymer resin region and a second polymer resin region having different heat shrinkage rates, and wherein the first polymer resin region and the second polymer resin region are heat-shrinkable. heat-shrinkable tubular substrates alternately disposed with each other in the longitudinal direction of the sex tubular substrates;

an inorganic material layer formed on the outer surface of the heat-shrinkable tubular substrate; and

There is provided a pouch for a flexible battery formed on the outer surface of the inorganic material layer and having a polymer resin layer made of a third polymer resin.

The first polymer resin and the second polymer resin are each independently selected from the group consisting of a polyolefin-based resin, a polyester-based resin, a polyamide-based resin, and a fluoro-based resin, or a mixture of two or more thereof. can be done

The inorganic layer may be any one selected from the group consisting of SiO ₂ , Al ₂ O ₃ , MgO, BaTiO ₃ , ZrO ₂ and ZnO, or a mixture of two or more thereof.

The third polymer resin is high-density polyethylene, low-density polyethylene, linear low-density polyethylene, ultra-high molecular weight polyethylene, polypropylene, polyethyleneterephthalate, polybutyleneterephthalate, polyester, polyacetal. , polyamide, polycarbonate, polyimide, polyetheretherketone, polyethersulfone, polyphenyleneoxide, polyphenylenesulfide and It may be any one selected from the group consisting of polyethylenenaphthalate or a mixture of two or more thereof.

The first polymer resin region may have a greater thermal contraction rate than the second polymer resin region.

The first polymer resin region may have a greater length than the second polymer resin region.

In order to solve the problem of the present invention, according to another aspect of the present invention,

An internal current collector, an internal electrode active material layer, an external electrode active material layer, a separation layer interposed between the internal electrode active material layer and the external electrode active material layer, and an external current collector formed outside the external electrode active material layer, longitudinal direction an electrode assembly extending to; and

A pouch for a flexible battery comprising a hollow part into which the electrode assembly is inserted, and formed in close contact with the outer surface of the electrode assembly inserted into the hollow part;

The flexible battery pouch is a heat-shrinkable tubular substrate extending in a longitudinal direction, wherein the heat-shrinkable tube has a first polymer resin region and a second polymer resin region having different heat shrinkage rates, the first polymer resin region and the second polymer a heat-shrinkable tubular substrate in which resin regions are alternately disposed in a longitudinal direction of the heat-shrinkable tubular substrate; an inorganic material layer formed on the outer surface of the heat-shrinkable tubular substrate; and a polymer resin layer formed on the outer surface of the inorganic material layer and made of a third polymer resin,

One region having a smaller thermal contraction rate among the first polymer resin region and the second polymer resin region is more contracted and closely adhered to the outer surface of the electrode assembly than the other regions, so that the outer surface of the flexible battery pouch is convex and concave. A flexible battery provided alternately is provided.

According to one aspect of the present invention,

Preparing a heat-shrinkable tubular substrate by alternately extruding a first polymer resin and a second polymer resin having different heat shrinkage rates, wherein the first polymer resin region and the second polymer resin region are alternately arranged with each other in the longitudinal direction;

forming an inorganic material layer on the outer surface of the heat-shrinkable tubular substrate; and

There is provided a method of manufacturing a pouch for a flexible battery comprising forming a polymer resin layer made of a third polymer resin on the outer surface of the inorganic material layer.

The step of preparing the heat-shrinkable tubular substrate comprises: two separate raw material injection units into which the first polymer resin and the second polymer resin are respectively injected; And it may be carried out using an extrusion molding apparatus having a path inducing part for opening and closing the transport path so that the first polymer resin and the second polymer resin are alternately transported to the extrusion part of the raw material injection part.

The forming of the inorganic layer may be performed by one or more methods of atomic layer deposition (ALD) and chemical vapor deposition (CVD).

The forming of the polymer resin layer may be performed by at least one of a method consisting of dip coating, spray coating, and polymer deposition.

after forming the polymer resin layer, forming the inorganic material layer; and forming a polymer resin layer made of a third polymer resin on the outer surface of the inorganic material layer one or more times.

In order to solve the problem of the present invention, according to another aspect of the present invention,

An internal current collector, an internal electrode active material layer, an external electrode active material layer, a separation layer interposed between the internal electrode active material layer and the external electrode active material layer, and an external current collector formed outside the external electrode active material layer, longitudinal direction Preparing an electrode assembly extending to the;

Inserting the electrode assembly into the hollow portion of the flexible battery pouch manufactured by the manufacturing method of any one of claims 1 to 5; and

There is provided a method of manufacturing a flexible battery comprising; heat-treating the pouch for a flexible battery into which the electrode assembly is inserted.

In the heat treatment step, heat is applied to the outer surface of the flexible battery pouch, so that one region having a smaller thermal contraction rate among the first polymer resin region and the second polymer resin region is more contracted on the outer surface of the electrode assembly than the other region. It may be a step of alternately having a convex portion and a concave portion on the outer surface of the flexible battery pouch by making it close.

According to an embodiment of the present invention, by introducing a heat-shrinkable tubular substrate formed by alternately disposing the first polymer resin region and the second polymer resin region having different thermal shrinkage rates in the longitudinal direction, the flexibility of the flexible secondary battery can be improved. In order to maximize it, it is possible to provide a pouch for a flexible secondary battery that can be flexibly deformed without the formation of cracks even when a compressive force such as bending is applied.

1 is a schematic diagram of a conventional pouch for a flexible secondary battery.
FIG. 2 is a schematic diagram illustrating a buckling phenomenon occurring during bending of a conventional pouch for a flexible secondary battery.
3 is a schematic diagram of a cross-section of a pouch for a flexible secondary battery obtained by a manufacturing method according to an embodiment of the present invention.
4 is a schematic diagram of a pouch for a flexible secondary battery obtained by a manufacturing method according to an embodiment of the present invention.
5 is a schematic diagram of a cross-section of a pouch for a flexible secondary battery obtained by a manufacturing method according to an embodiment of the present invention after heat-shrinkage treatment.
6 is a schematic view after heat-shrink processing of the pouch for a flexible secondary battery obtained by the manufacturing method according to an embodiment of the present invention.
7 is a schematic diagram of a flexible secondary battery provided with a pouch for a flexible secondary battery obtained by the manufacturing method according to an embodiment of the present invention.
8 is a schematic diagram of a raw material supply unit of an extrusion molding apparatus used in a method of manufacturing a pouch for a flexible secondary battery according to an embodiment of the present invention.
9A and 9B are schematic diagrams illustrating an operation process of a raw material supply unit of an extrusion molding apparatus used in a method of manufacturing a pouch for a flexible secondary battery according to an embodiment of the present invention.
10 is a schematic diagram of an extrusion molding apparatus used in a method of manufacturing a pouch for a flexible secondary battery according to an embodiment of the present invention.
11 is a schematic diagram of an operation process of an extrusion molding apparatus used in a method of manufacturing a pouch for a flexible secondary battery according to an embodiment of the present invention.
12 is a schematic diagram of a polymer resin layer forming process used in a method of manufacturing a pouch for a flexible secondary battery according to an embodiment of the present invention.

Hereinafter, the present invention will be described in detail. Prior to this, the terms or words used in the present specification and claims should not be construed as being limited to conventional or dictionary meanings, and the inventor should properly understand the concept of the term in order to best describe his invention. Based on the principle that it can be defined, it should be interpreted as meaning and concept consistent with the technical idea of the present invention. Accordingly, the configurations described in the drawings other than the embodiments described in this specification are only the most preferred embodiment of the present invention and do not represent all the technical spirit of the present invention, so various equivalents that can be substituted for them at the time of the present application It should be understood that there may be variations and variations.

3 is a schematic diagram of a cross-section of a pouch for a flexible secondary battery according to an embodiment of the present invention, and FIG. 4 is a schematic diagram of a pouch for a flexible secondary battery according to an embodiment of the present invention.

3 and 4, the flexible secondary battery pouch 20 according to an aspect of the present invention is a heat-shrinkable tubular substrate 21 extending in the longitudinal direction, wherein the heat-shrinkable tube is a first polymer having a different heat shrinkage rate. a resin region (A) and a second polymer resin region (B), wherein the first polymer resin region (A) and the second polymer resin region (B) are alternately arranged in the longitudinal direction of the heat-shrinkable tubular substrate a heat-shrinkable tubular substrate 21 being;

an inorganic material layer 22 formed on the outer surface of the heat-shrinkable tubular substrate; and

A polymer resin layer 23 formed on the outer surface of the inorganic material layer and made of a third polymer resin is provided.

The heat-shrinkable tubular substrate is a substrate formed in a tube shape by alternately extruding a first polymer resin and a second polymer resin having different heat shrinkage characteristics, that is, a heat shrinkage rate. On the other hand, the conventional flexible secondary battery pouch is formed by laminating a polymer resin layer, a metal foil layer, and a mechanical support layer in the order of a sheet form like a pouch of a conventional secondary battery, and then wound up in a tube form to create a space inside, and then both ends are wound up. manufactured by gluing.

Therefore, the pouch according to an embodiment of the present invention uses a heat-shrinkable tubular substrate obtained by being extruded into a tubular shape in the first place, and unlike the conventional pouches that only have a tube shape in appearance, flexibility is greatly increased without worrying about cracking during bending or bending. can be improved.

The heat-shrinkable tubular substrate is a tube that shrinks when heated, and serves to tightly wrap terminals or materials of different shapes and sizes, and is made of polymer resin and is used for insulation or other purposes. . As such heat-shrinkable tube, heat-shrinkable tube having various materials and shapes is commercially available, so that one suitable for the purpose of the present invention can be easily obtained and used. At this time, it is necessary to set the temperature of the shrinkage process to a low temperature so as not to cause thermal damage to the secondary battery, and in general, it is required to complete the shrinkage at a temperature of 70°C to 200°C or 70°C to 120°C.

As the first polymer resin and the second polymer resin, any material that is selected to have different thermal shrinkage rates and can be extruded into a tubular substrate may be used without limitation. For example, the first polymer resin and the second polymer resin are each independently polyolefin-based resins such as polyethylene and polypropylene, polyester-based resins such as polyethylene terephthalate, polyamide-based resins, and polyvinylidene fluoride , any one selected from the group consisting of fluoro-based resins such as polytetrafluoroethylene, or a mixture of two or more thereof may be used.

At this time, the difference between the heat shrinkage rate of the first polymer resin and the second polymer resin may be 1.5 to 3, and specifically, the values of the heat shrinkage rate of the first polymer resin and the second polymer resin are 2 to 2.5 and 3, respectively. to 5 days.

In addition, the heat shrinkage rate can be confirmed by a method of measuring the amount of change in diameter or length before/after heat shrinkage.

According to an embodiment of the present invention, the length of the first polymer resin region (A) and the second polymer resin region (B) may be the same or different from each other, and the length may be variously adjusted. do. In addition, the interface between the first polymer resin region (A) and the second polymer resin region (B) may be perpendicular to the longitudinal direction of the heat-shrinkable tubular substrate, or a diagonal direction with a slope in one direction, a wavy direction, etc. Various directions are possible.

An inorganic material layer is formed on the outer surface of the heat-shrinkable tubular substrate.

In a conventional conventional pouch for secondary batteries or a pouch for flexible secondary batteries, a metal foil layer is used as a barrier layer for preventing moisture penetration. However, even if the metal foil layer is wound in a tubular shape, flexibility is not uniformly exhibited in the entire area during bending, and there is a limitation in that the bending phenomenon occurs in some areas and develops into cracks. However, in an embodiment of the present invention, an inorganic material layer, not a metal foil, is formed as a barrier layer to provide resistance to moisture penetration, and is formed in close contact with a heat-shrinkable tubular substrate, which is the innermost substrate. It plays a role in greatly improving the flexibility so that the flexibility can be exhibited as it is without loss. The inorganic layer may include any one selected from the group consisting of SiO ₂ , Al ₂ O ₃ , MgO, BaTiO ₃ , ZrO ₂ and ZnO, or a mixture of two or more thereof.

The inorganic layer may be formed by using such inorganic particles as atomic layer deposition (ALD) or chemical vapor deposition (CVD).

In addition, the polymer resin layer is formed on the outer surface of the inorganic material layer, and consists of a third polymer resin. The polymer resin layer is formed on the outermost side of the pouch and serves as a mechanical support layer to prevent damage to the inner component layer of the pouch or the secondary battery due to external force or the like.

The third polymer resin of the polymer resin layer includes high-density polyethylene, low-density polyethylene, linear low-density polyethylene, ultra-high molecular weight polyethylene, polypropylene, polyethyleneterephthalate, polybutyleneterephthalate, polyester, Polyacetal, polyamide, polycarbonate, polyimide, polyetheretherketone, polyethersulfone, polyphenyleneoxide, polyphenylene It may be formed of any one selected from the group consisting of sulfide (polyphenylenesulfide) and polyethylenenaphthalate (polyethylenenaphthalate), or a mixture of two or more thereof.

In the forming of the polymer resin layer, a polymer coating method commonly used in the art, such as a dip coating method, a spray coating method, and polymer deposition, may be applied.

The inorganic material layer and the polymer resin layer may be formed one layer each on the outside of the heat-shrinkable tubular substrate, and as long as the flexibility of the flexible secondary battery pouch is maintained, two or more layers may be alternately formed with each other.

When the inorganic material layer and the polymer resin layer are each formed in two layers, the pouch 20 for a flexible secondary battery according to an aspect of the present invention is a heat-shrinkable tubular substrate 21 extending in the longitudinal direction, wherein the heat-shrinkable tube is A first polymer resin region (A) and a second polymer resin region (B) having different heat shrinkage rates are provided, wherein the first polymer resin region (A) and the second polymer resin region (B) are the heat-shrinkable tubular substrates. Heat-shrinkable tubular substrates 21 alternately arranged with each other in the longitudinal direction; an inorganic material layer 22 formed on the outer surface of the heat-shrinkable tubular substrate; a polymer resin layer 23 formed on the outer surface of the inorganic material layer and made of a third polymer resin; an inorganic material layer 24 formed on the outer surface of the polymer resin layer 23; A polymer resin layer 25 made of a third polymer resin formed on the outer surface of the inorganic material layer may be provided.

5 is a schematic diagram of a cross-section of the pouch for a flexible secondary battery according to an embodiment of the present invention after heat-shrink treatment, and FIG. 6 is a schematic view after heat-shrink treatment of the pouch for a flexible secondary battery according to an embodiment of the present invention.

5 and 6, a case in which the second polymer resin region (B) of the first polymer resin region (A) and the second polymer resin region (B) has a greater thermal contraction rate than the first polymer resin region (A) It is described by way of example, but is not limited thereto.

The pouch 20 for a flexible secondary battery of FIG. 5 is heat-shrinked when the pouch 20 for a flexible secondary battery of FIG. 3 is heat treated and heated. At this time, the second polymer resin region (B) is the first polymer resin region ( Since the heat shrinkage rate is greater than that of A), as the second polymer resin region (B) heats up to a greater extent, a concave portion is formed in the second polymer resin region (B), and the first polymer resin having a relatively large heat shrinkage rate A convex portion is formed in the region A.

Referring to FIG. 6 , when the pouch 20 for a flexible secondary battery of FIG. 4 was previously heated, concave portions and convex portions on the surface according to the difference in heat shrinkage were alternately formed in the longitudinal direction. Check the outer surface of the pouch for a flexible secondary battery. can

The pouch for a flexible secondary battery according to an embodiment of the present invention has a concave portion and a convex portion, that is, a curved shape, formed in the longitudinal direction on the surface through this heat treatment, so that, unlike the conventional pouch, there is a bending action in various directions by an external force. With the concave part as the central point, the force is dispersed, so that problems such as cracks due to bending do not occur, and it can be flexibly deformed into various shapes.

7 is a schematic diagram of a flexible secondary battery provided with a pouch for a flexible secondary battery according to an embodiment of the present invention.

Referring to FIG. 7 , the flexible secondary battery according to an embodiment of the present invention includes an internal current collector 320 , an internal electrode active material layer 330 , an external electrode active material layer 360 , the internal electrode active material layer 330 and An electrode assembly 300 having a separation layer 340 interposed between the external electrode active material layers 360 and an external current collector 350 formed outside the external electrode active material layer 360 and extending in the longitudinal direction. ; and

A flexible battery pouch 20 that includes a hollow part into which the electrode assembly 300 is inserted, and is formed in close contact with the outer surface of the electrode assembly inserted into the hollow part;

The flexible battery pouch is a heat-shrinkable tubular substrate 21 extending in a longitudinal direction, wherein the heat-shrinkable tube has a first polymer resin region and a second polymer resin region having different heat shrinkage rates, the first polymer resin region and a heat-shrinkable tubular substrate 21 in which second polymer resin regions are alternately disposed in a longitudinal direction of the heat-shrinkable tubular substrate; an inorganic material layer 22 formed on the outer surface of the heat-shrinkable tubular substrate; and a polymer resin layer 23 formed on the outer surface of the inorganic material layer and made of a third polymer resin,

One region having a smaller thermal contraction rate among the first polymer resin region and the second polymer resin region is more contracted and closely adhered to the outer surface of the electrode assembly than the other regions, so that the outer surface of the flexible battery pouch is convex and concave. alternately provided

At this time, as described above, when the inorganic material layer and the polymer resin layer are each formed in two layers, the inorganic material layer 24 formed on the outer surface of the polymer resin layer 23; A polymer resin layer 25 made of a third polymer resin formed on the outer surface of the inorganic material layer may be provided.

In this case, the electrode assembly 300 may have a cross-section of a predetermined shape. The predetermined shape means that the shape is not particularly limited, and any shape that does not impair the essence of the present invention is possible. More specifically, it may be a circle or a polygon, and the circle may be a geometrically perfectly symmetrical circle and an asymmetrical elliptical structure, and non-limiting examples of the polygonal structure may be a triangle, a square, a pentagon, or a hexagon.

The flexible secondary battery of the present invention has a cross section of a predetermined shape, has a linear structure elongated in the longitudinal direction with respect to the cross section, and has flexibility, so that deformation is free.

Here, the external current collector is shown in the form of a spirally wound sheet in FIG. 7, but is not limited thereto, and a current collector or a metal paste coating layer in a spirally wound wire form, a half pipe form, or a mesh form may be used. can

When a half-pipe type current collector is used, two or three pieces may be used by bonding to the inside of the heat-shrinkable tubular substrate of the pouch so as to completely cover the outer surface of the electrode assembly. However, at this time, in consideration of the case where the tube is heat-shrinked, it is arranged to maintain a constant interval.

In the case of using the current collector in the form of a mesh, a certain degree of elasticity is ensured, and thus the electrode assembly may be cut and used to completely cover the outer surface of the electrode assembly.

In addition, when using a metal paste, it can be used by coating the inner surface of the heat-shrinkable tubular substrate of the pouch.

The internal current collector may be a spirally wound wire type, a half pipe type, or a mesh type current collector.

At this time, the internal current collector or the external current collector, each independently of each other, stainless steel, aluminum, nickel, titanium, sintered carbon, copper; stainless steel surface-treated with carbon, nickel, titanium or silver; aluminum-cadmium alloy; Non-conductive polymer surface-treated with a conductive material; Alternatively, one prepared using a conductive polymer may be used, and the present invention is not particularly limited thereto. Polyacetylene, polyaniline, polypyrrole, polythiophene and polysulfurnitride, ITO (Indum Tin Oxide), copper, silver, palladium, nickel, etc. are possible as the conductive material, and the conductive polymer is polyacetylene, polyaniline, polypyrrole, Polythiophene and polysulfurnitride can be used.

Here, the internal electrode includes an internal current collector and an internal electrode active material layer formed on an outer surface of the internal current collector, and the external electrode includes an external current collector and an external electrode active material layer formed on an external surface or one surface of the external current collector and may be a negative electrode and a positive electrode, respectively, or a positive electrode and a negative electrode.

When the internal electrode or the external electrode acts as a negative electrode, the active material layer may include natural graphite, artificial graphite, carbonaceous material; lithium-containing titanium composite oxide (LTO), Si, Sn, Li, Zn, Mg, Cd, Ce, Ni or Fe metals (Me); alloys composed of the metals (Me); oxides (MeOx) of the metals (Me); and a composite of the metal (Me) and carbon may be used.

In addition, when the internal electrode or the external electrode acts as a positive electrode, the active material layer includes LiCoO ₂ , LiNiO ₂ , LiMn ₂ O ₄ , LiCoPO ₄ , LiFePO ₄ , LiNiMnCoO ₂ and LiNi _1-xyz Co _x M1 _y M2 _z O ₂ (M1 and M2 are each independently any one selected from the group consisting of Al, Ni, Co, Fe, Mn, V, Cr, Ti, W, Ta, Mg and Mo, and x, y and z are Independently of each other, 0 ≤ x < 0.5, 0 ≤ y < 0.5, 0 ≤ z < 0.5, 0 < x+y+z ≤ 1) may be used as the atomic fraction of the oxide composition elements.

The separation layer 340 of the present invention may use an electrolyte layer or a separator. Examples of the electrolyte layer serving as a passage for these ions include a gel-type polymer electrolyte using PEO, PVdF, PVdF-HFP, PMMA, PAN, or PVAc; or a solid electrolyte using PEO, polypropylene oxide (PPO), polyethylene imine (PEI), polyethylene sulphide (PES), or polyvinyl acetate (PVAc); use etc. The matrix of the solid electrolyte is preferably made of a polymer or ceramic glass as a basic skeleton. In the case of a general polymer electrolyte, even if ion conductivity is satisfied, ions can move very slowly in terms of reaction rate, so it is preferable to use a gel-type polymer electrolyte in which ions move more easily than in the case of a solid. Since the gel-type polymer electrolyte does not have excellent mechanical properties, it may include a pore structure support or a cross-linked polymer to compensate for this. Since the electrolyte layer of the present invention can serve as a separator, a separate separator may not be used.

The electrolyte layer of the present invention may further include a lithium salt. Lithium salts can improve ionic conductivity and reaction rate, including, but not limited to, LiCl, LiBr, LiI, LiClO ₄ , LiBF ₄ , LiB ₁₀ Cl ₁₀ , LiPF ₆ , LiCF ₃ SO ₃ , LiCF ₃ CO ₂ , LiAsF ₆ , LiSbF ₆ , LiAlCl ₄ , CH ₃ SO ₃ Li, CF ₃ SO ₃ Li, (CF ₃ SO ₂ ) ₂ NLi, lithium chloroborane, lithium lower aliphatic carboxylate, lithium tetraphenylborate, etc. can be used. have.

Although the type of the separator is not limited, the separator is made of a polyolefin-based polymer selected from the group consisting of ethylene homopolymer, propylene homopolymer, ethylene-butene copolymer, ethylene-hexene copolymer, and ethylene-methacrylate copolymer. write; a porous substrate made of a polymer selected from the group consisting of polyester, polyacetal, polyamide, polycarbonate, polyimide, polyether ether ketone, polyether sulfone, polyphenylene oxide, polyphenylene sulfide and polyethylene naphthalate; Alternatively, a porous substrate formed of a mixture of inorganic particles and a binder polymer may be used.

And, according to an embodiment of the present invention, the internal electrode may be in a form that further includes a lithium ion supply core part 310 optionally including an electrolyte, in this case, the internal electrode is the lithium ion supply core part One or more wire-type inner current collectors 320 wound around the outer surface of the 310 and the inner electrode active material layer 230 formed on the surface of the wire-type inner current collector 320 are provided.

Since the electrolyte of the lithium ion supply core part easily penetrates into the active material of the electrode, it is possible to facilitate the supply of lithium ions and the exchange of lithium ions, thereby further improving the capacity characteristics and cycle characteristics of the battery.

The lithium ion supply core part includes an electrolyte, and the type of the electrolyte is not particularly limited, but ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), vinylene carbonate (VC), Diethyl carbonate (DEC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), methyl formate (MF), gamma-butyrolactone (γ-BL; butyrolactone), sulfolane (sulfolane), methyl acetate ( MA; methylacetate), or a non-aqueous electrolyte using methylpropionate (MP; methylpropionate); gel-type polymer electrolytes using PEO, PVdF, PVdF-HFP, PMMA, PAN or PVAc; or a solid electrolyte using PEO, polypropylene oxide (PPO), polyethylene imine (PEI), polyethylene sulphide (PES), or polyvinyl acetate (PVAc); etc. can be used. In addition, the electrolyte may further include a lithium salt, such as LiCl, LiBr, LiI, LiClO ₄ , LiBF ₄ , LiB ₁₀ Cl ₁₀ , LiPF ₆ , LiCF ₃ SO ₃ , LiCF ₃ CO ₂ , LiAsF ₆ , LiSbF ₆ , LiAlCl ₄ , CH ₃ SO ₃ Li, CF ₃ SO ₃ Li, (CF ₃ SO ₂ ) ₂ NLi, lithium chloroborane, lithium lower aliphatic carboxylate, lithium tetraphenylborate, etc. are preferably used. do. In addition, the lithium ion supply core 210 may be configured only with an electrolyte, and in the case of a liquid electrolyte, it may be configured using a porous carrier.

A method of manufacturing a pouch for a flexible battery according to an aspect of the present invention,

Preparing a heat-shrinkable tubular substrate by alternately extruding a first polymer resin and a second polymer resin having different heat shrinkage rates, wherein the first polymer resin region and the second polymer resin region are alternately arranged with each other in the longitudinal direction;

forming an inorganic material layer on the outer surface of the heat-shrinkable tubular substrate; and

and forming a polymer resin layer made of a third polymer resin on the outer surface of the inorganic material layer.

First, in the step of preparing the heat-shrinkable tubular substrate, the first polymer resin and the second polymer resin having different heat shrinkage rates are alternately extruded so that the first polymer resin region and the second polymer resin region are alternately arranged in the longitudinal direction. It is a step for producing a sexual tubular substrate.

Specifically, the step of preparing the heat-shrinkable tubular substrate may include: two separate raw material injection units into which the first polymer resin and the second polymer resin are respectively injected; And it may be carried out using an extrusion molding apparatus having a path inducing part for opening and closing the transport path so that the first polymer resin and the second polymer resin are alternately transported to the extrusion part of the raw material injection part.

8 is a schematic diagram of a raw material supply unit of an extrusion molding apparatus used in a method of manufacturing a pouch for a flexible secondary battery according to an embodiment of the present invention. The raw material supply unit 30 is configured to alternately transfer the second polymer resin raw material injection unit 31 , the first polymer resin raw material injection unit 32 , and the first polymer resin and the second polymer resin to the main body of the extrusion molding apparatus. A path guide part 33 for opening and closing the transport path may be provided.

As an example of the path inducing part, as shown in FIG. 8 , a transport path may be formed between the first polymer resin injection part and the second polymer resin injection part and into which the second polymer resin is injected, but is not limited thereto. However, if the path guide unit can alternately transfer the first polymer resin and the second polymer resin to the extrusion unit, it can be applied in various forms, and its installation position can be appropriately applied. At this time, with respect to the height (t _b , ta ) of the transport path from the second polymer resin raw material injection unit 31 and the first polymer resin raw material injection unit 32 to the path guide unit 33 , _{t a is} t It can be formed larger than _b , and in this case, opening and closing can be performed more reliably so that the polymer resin raw material can be alternately transferred to the main body of the extrusion molding apparatus in the transfer path part.

9A and 9B are schematic diagrams illustrating an operation process of a raw material supply unit of an extrusion molding apparatus used in a method of manufacturing a pouch for a flexible secondary battery according to an embodiment of the present invention.

9A and 9B, when the path guide part 33 moves downward, the passage of the first polymer resin raw material injection part 32 to the main body of the extrusion molding apparatus is closed, and the second polymer resin raw material injection part 31 is closed. The passage to the main body of the extrusion molding apparatus is opened, so that the second polymer resin (b) can be injected into the main body of the extrusion molding apparatus. ) is opened to the main body of the extrusion molding apparatus, and the passage to the main body of the extrusion molding apparatus of the second polymer resin raw material injection unit 31 is closed, so that the second polymer resin (b) is injected into the main body of the extrusion molding apparatus. is stopped, and the first polymer resin (a) can be injected into the main body of the extrusion molding apparatus.

At this time, if the cycle of the vertical movement of the path guide part 33 is adjusted, the contents of the first polymer resin (a) and the second polymer resin (b) transferred to the main body of the extrusion molding apparatus can be properly supplied alternately, In the final heat-shrinkable tubular substrate, the first polymer resin region (A) and the second polymer resin region (B) having different rates of heat shrinkage in the longitudinal direction may be provided.

In the method of manufacturing a pouch for a flexible secondary battery according to an embodiment of the present invention, an extrusion molding apparatus equipped with the above-described raw material supply unit may be used, and as such an extrusion molding apparatus, as described above in the apparatus for forming a tubular substrate in the art. If the raw material supply unit can be equipped, it can be applied without limitation.

A schematic diagram of an example of such an extrusion molding apparatus 100 and a schematic diagram of its operation process are shown in FIGS. 10 and 11 .

Referring to FIG. 10, the extrusion molding apparatus 100 includes two extruding parts 112a, 112b and the above-described raw material supply unit 30 connected to the extruding parts 112a and 112b, and the raw material supply unit ( 30 is again arranged and configured to be perpendicular to the crosshead-type long die 114 in a horizontal plane.

The head part 120 includes two extruded parts 112a and 112b having a screw 118 mounted inside the cylinder 116; The above-described raw material supply unit 30 in communication with the two extrusion units, respectively; The length of the main body 124 and the inner hole of the main body 124, which is fixedly connected to the front end of the raw material supply unit 30 and has an inner hole having a horizontal cross section showing a curved shape, and the length of the extruded portion 112 and a shim holder 126 disposed so as to be orthogonal to the direction.

A flow path through which the first polymer resin and the second polymer resin flow is formed between the inner surface of the main body 124 and the outer peripheral surface of the deep holder 126 . In addition, one open end of the inner hole of the main body portion 124 is connected to the open end of the raw material supply unit 30 so that it can communicate, while the other open end is connected to the long die unit 122, In this case, the first polymer resin and the second polymer resin extruded by the raw material supply unit 30 are press-fitted into the narrowed long die unit 122 through the flow path of the head unit 120 . In addition, a heating device is installed in the head part 120 so that the temperature of the head part 120 can be adjusted so that soot is not caused while maintaining the fluidization of the first polymer resin and the second polymer resin, which are raw materials, for example. For example, it can be adjusted so that it may become 100 degrees C or less.

In addition, the long dice part 122 integrally installed on the head part 120 is composed of a long pipe-shaped cylindrical body 128 that is a dice body and a nipple 130 as a deep mold, and this nipple 130 is the head. By being immovably fixedly supported by the deep-shaped holder 126 of the portion 120, it is concentrically disposed in the tubular body 128 having an inner diameter greater than the outer diameter of the nipple 130, and the inner circumferential surface of these tubular bodies 128 and the nipple ( 130) becomes a die gap through which raw materials (the first polymer resin and the second polymer resin) forming the heat-shrinkable tubular substrate flow.

In the long die part 122, a heating part 134 having a heating member 132 introduced thereinto on the outer peripheral surface of the cylindrical body 128, and a cooling member 136 such as a cooling pipe 135 through which the coolant can flow. The heating part 134 and the cooling part 138 are provided by being installed sequentially toward the extrusion direction (up-and-down direction in the figure) of a temporary raw material. That is, in the heating unit 134 located on the side of the head 120 , the raw material can move therein, and a heat-shrinkable tubular substrate is formed, while in the cooling unit 138 on the side of the open end 140 . The tubular substrate formed by the heating unit 134 can be cooled.

In addition, the elongated die portion 122 is a tapered portion 142 whose inner peripheral surface located on the opening side is gradually enlarged toward the open end 140 , and the entire inner peripheral surface of the cooling portion 138 is tapered 142 . ) is made.

Referring to FIG. 11 , in the above-described extrusion molding apparatus 100 , a first polymer resin and a second polymer resin having different thermal contraction rates are alternately supplied as a raw material through the raw material supply unit 30 to form a first polymer resin region in the longitudinal direction. A heat-shrinkable tubular substrate may be manufactured by molding the compressed product 152 in which (A) and the second polymer resin region (B) are alternately formed in the longitudinal direction. In this case, the first polymer resin and the second polymer resin are the same as described above.

Next, a step of forming an inorganic material layer on the outer surface of the heat-shrinkable tubular substrate is performed. As described above, the inorganic layer may include any one selected from the group consisting of SiO ₂ , Al ₂ O ₃ , MgO, BaTiO ₃ , ZrO ₂ and ZnO, or a mixture of two or more thereof. The inorganic layer may be formed by using such inorganic particles as atomic layer deposition (ALD) or chemical vapor deposition (CVD).

Next, a step of forming a polymer resin layer made of a third polymer resin on the outer surface of the inorganic material layer is performed.

The third polymer resin of the polymer resin layer is as described above, and the step of forming the polymer resin layer is a polymer coating method commonly used in the art, such as a dip coating method, a spray coating method, and polymer deposition. can do. For example, in the case of the dip coating method, a heat-shrinkable tubular substrate having an inorganic material layer formed on the surface is immersed in a coating tank in which a molten third polymer resin is stored, a polymer resin layer is applied to the surface, and then the polymer is processed such as cooling. A resin layer can be formed.

12 is a schematic diagram of a polymer resin layer forming process used in a method of manufacturing a pouch for a flexible secondary battery according to an embodiment of the present invention.

12, the polymer resin layer forming apparatus 200 includes a supply roller 220 for supplying a heat-shrinkable tubular substrate 210 having an inorganic material layer formed on its surface, and a heat-shrinkable tubular substrate 210 on which the supplied inorganic material layer is formed. ) and a polymer resin coating tank 230 for applying a polymer resin layer to the surface by immersion.

The polymer resin coating tank 230 can store the polymer resin in a molten state through temperature control, and the heat-shrinkable tubular substrate in which the polymer resin melted through the polymer resin coating tank is applied to the surface of the inorganic material layer is then cooled The polymer resin layer can be finally formed through a post-process, such as.

The temperature of the polymer resin coating tank can be appropriately adjusted according to the melting point of the third polymer resin used, and in the case of an acrylic polymer resin such as polyacrylate, or a polyolefin polymer resin, it has a melting point of about 200 ° C. Bar, It can be adjusted to a temperature about 50 ℃ higher than the melting point.

The inorganic material layer and the polymer resin layer may be formed one layer each on the outside of the heat-shrinkable tubular substrate, and as long as the flexibility of the flexible secondary battery pouch is maintained, two or more layers may be alternately formed with each other.

Therefore, after the step of forming the polymer resin layer, forming the inorganic material layer; and forming a polymer resin layer made of a third polymer resin on the outer surface of the inorganic material layer one or more times.

According to another aspect of the present invention, an internal current collector, an internal electrode active material layer, an external electrode active material layer, a separation layer interposed between the internal electrode active material layer and the external electrode active material layer, and an external formed outside the external electrode active material layer Preparing an electrode assembly having a current collector and extending in the longitudinal direction;

inserting the electrode assembly into a hollow portion of a pouch for a flexible battery manufactured by the above-described manufacturing method; and

There is provided a method of manufacturing a flexible battery comprising; heat-treating the pouch for a flexible battery into which the electrode assembly is inserted.

First, in the step of preparing the electrode assembly, an inner electrode active material layer is formed on the outer surface of the inner current collector, and then a separator layer or an electrolyte layer is coated or wound on the inner electrode active material layer as a separation layer. It may be prepared by introducing an external current collector on which the electrode active material layer is formed on the separation layer.

In this case, methods commonly applied in the art may be used for the formation of the inner electrode active material layer and the outer electrode active material layer, and the formation method of the separation layer.

Next, a step of inserting the electrode assembly into the hollow portion of the pouch for a flexible battery manufactured by the above-described manufacturing method is performed.

In the heat treatment, heat is applied to the outer surface of the flexible battery pouch, so that one region having a greater thermal contraction rate among the first polymer resin region and the second polymer resin region is more contracted on the outer surface of the electrode assembly than the other region. It may be a step of alternately having a convex portion and a concave portion on the outer surface of the flexible battery pouch by adhering to it.

The heat treatment step may be performed at a temperature of 100 to 200° C. using a hollow heating device opened in the longitudinal direction of the cuboid.

On the other hand, the embodiments of the present invention disclosed in the present specification and drawings are merely presented as specific examples to aid understanding, and are not intended to limit the scope of the present invention. It will be apparent to those of ordinary skill in the art to which the present invention pertains that other modifications based on the technical spirit of the present invention can be implemented in addition to the embodiments disclosed herein.

10: conventional flexible secondary battery tubular pouch 11: polymer resin layer
12: metal foil layer 13: mechanical support layer
A: first polymer resin region B: second polymer resin region
20: flexible secondary battery pouch 21: heat-shrinkable tubular substrate 22: inorganic material layer
23: polymer resin layer 24: inorganic material layer 25: polymer resin layer
30: raw material supply unit 31: second polymer resin raw material injection unit
32: first polymer resin raw material injection unit 33: path induction unit
a: first polymer resin b: second polymer resin
100: extrusion molding apparatus 112a, 112b: extruding part 114: long die
116a, 116b: cylinder 118a, 118b: screw
Reference Numerals 120: Head 122: Long Dice 124: Main Body 126: Deep Holder 128: Cylinder
130: nipple 132: heating member 134: heating unit 135: cooling pipe 136: cooling member 138: cooling unit
140: open end 142: tapered portion 152: extrudate
220: polymer resin layer forming device
210: heat-shrinkable tubular substrate with an inorganic layer formed on the surface
220: supply roller 230: polymer resin coating tank
300: electrode assembly 310: 320: inner current collector 330: inner electrode active material layer
340: separation layer 350: external current collector 360: external electrode active material layer

Claims (14)

A heat-shrinkable tubular substrate extending in a longitudinal direction, wherein the heat-shrinkable tube has a first polymer resin region and a second polymer resin region having different heat shrinkage rates, and wherein the first polymer resin region and the second polymer resin region are heat-shrinkable. heat-shrinkable tubular substrates alternately disposed with each other in the longitudinal direction of the sex tubular substrates;
an inorganic material layer formed on the outer surface of the heat-shrinkable tubular substrate; and
A pouch for a flexible battery formed on the outer surface of the inorganic material layer and having a polymer resin layer made of a third polymer resin. According to claim 1,
The first polymer resin and the second polymer resin are each independently selected from the group consisting of a polyolefin-based resin, a polyester-based resin, a polyamide-based resin, and a fluoro-based resin, or a mixture of two or more thereof. A pouch for flexible batteries. According to claim 1,
The inorganic layer is any one selected from the group consisting of SiO ₂ , Al ₂ O ₃ , MgO, BaTiO ₃ , ZrO ₂ and ZnO, or a mixture of two or more thereof. According to claim 1,
The third polymer resin is high-density polyethylene, low-density polyethylene, linear low-density polyethylene, ultra-high molecular weight polyethylene, polypropylene, polyethyleneterephthalate, polybutyleneterephthalate, polyester, polyacetal. , polyamide, polycarbonate, polyimide, polyetheretherketone, polyethersulfone, polyphenyleneoxide, polyphenylenesulfide and A pouch for a flexible battery that is any one selected from the group consisting of polyethylenenaphthalate or a mixture of two or more thereof. According to claim 1,
A pouch for a flexible battery in which the first polymer resin region has a greater thermal contraction rate than the second polymer resin region. 6. The method of claim 5,
A pouch for a flexible battery in which the first polymer resin region has a greater length than the second polymer resin region. An internal current collector, an internal electrode active material layer, an external electrode active material layer, a separation layer interposed between the internal electrode active material layer and the external electrode active material layer, and an external current collector formed outside the external electrode active material layer, longitudinal direction an electrode assembly extending to; and
A pouch for a flexible battery comprising a hollow part into which the electrode assembly is inserted, and formed in close contact with the outer surface of the electrode assembly inserted into the hollow part;
The flexible battery pouch is a heat-shrinkable tubular substrate extending in a longitudinal direction, wherein the heat-shrinkable tube has a first polymer resin region and a second polymer resin region having different heat shrinkage rates, the first polymer resin region and the second polymer a heat-shrinkable tubular substrate in which resin regions are alternately disposed in a longitudinal direction of the heat-shrinkable tubular substrate; an inorganic material layer formed on the outer surface of the heat-shrinkable tubular substrate; and a polymer resin layer formed on the outer surface of the inorganic material layer and made of a third polymer resin,
One region having a smaller thermal contraction rate among the first polymer resin region and the second polymer resin region is more contracted and closely adhered to the outer surface of the electrode assembly than the other regions, so that the outer surface of the flexible battery pouch is convex and concave. Flexible batteries provided alternately. Preparing a heat-shrinkable tubular substrate by alternately extruding a first polymer resin and a second polymer resin having different heat shrinkage rates, wherein the first polymer resin region and the second polymer resin region are alternately arranged with each other in the longitudinal direction;
forming an inorganic material layer on the outer surface of the heat-shrinkable tubular substrate; and
A method of manufacturing a pouch for a flexible battery comprising the step of forming a polymer resin layer made of a third polymer resin on the outer surface of the inorganic material layer. 9. The method of claim 8,
The step of preparing the heat-shrinkable tubular substrate comprises: two separate raw material injection units into which the first polymer resin and the second polymer resin are respectively injected; and a method for manufacturing a pouch for a flexible battery carried out using an extrusion molding device having a path inducing unit for opening and closing a transport path so that the first polymer resin and the second polymer resin are alternately transferred to the extrusion unit in the raw material injection unit. 9. The method of claim 8,
A method of manufacturing a pouch for a flexible battery in which the step of forming the inorganic layer is carried out by at least one of a method consisting of an atomic layer deposition (ALD) and a chemical vapor deposition (CVD). 9. The method of claim 8,
A method of manufacturing a pouch for a flexible battery in which the step of forming the polymer resin layer is carried out by at least one of a method consisting of dip coating, spray coating, and polymer deposition. 9. The method of claim 8,
after forming the polymer resin layer, forming the inorganic material layer; and forming a polymer resin layer made of a third polymer resin on the outer surface of the inorganic material layer at least once more. An internal current collector, an internal electrode active material layer, an external electrode active material layer, a separation layer interposed between the internal electrode active material layer and the external electrode active material layer, and an external current collector formed outside the external electrode active material layer, longitudinal direction Preparing an electrode assembly extending to the;
Inserting the electrode assembly into the hollow portion of the flexible battery pouch of any one of claims 1 to 6; and
A method of manufacturing a flexible battery comprising a; heat-treating the pouch for a flexible battery into which the electrode assembly is inserted. 14. The method of claim 13,
In the heat treatment step, heat is applied to the outer surface of the flexible battery pouch, so that one region having a greater thermal contraction rate among the first polymer resin region and the second polymer resin region is more contracted on the outer surface of the electrode assembly than the other region. A method of manufacturing a flexible battery, which is a step of alternately having a convex part and a concave part on the outer surface of the flexible battery pouch by being in close contact with each other.

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