KR102128094B1 - Cable-type secondary battery and preparation method thereof - Google Patents

Abstract

The present invention relates to a cable-type secondary battery and a method for manufacturing the same, comprising an inner electrode, an outer layer formed around an outer surface of the inner electrode, and a separation layer preventing short circuit of the electrode and an outer electrode formed surrounding the separation layer. Cable electrode assembly; And it relates to a cable-type secondary battery and a manufacturing method thereof, including a sheet-like packaging formed by spirally wound around the outer surface of the cable-type electrode assembly.
According to the present invention, even when a strong external force such as bending is applied to the cable-type secondary battery, the sheet-shaped packaging formed by spirally winding on the outer surface of the cable-type secondary battery can disperse the external force, whereby the surface of the packaging is bent or Wrinkles can be prevented.

Description

Cable-type secondary battery and its manufacturing method {Cable-type secondary battery and preparation method thereof}

The present invention relates to a cable-type secondary battery that can be freely deformed and a method for manufacturing the same, and more particularly, to a cable-type secondary battery that further improves flexibility by using sheet-shaped packaging and a method for manufacturing the same.

A secondary battery refers to a device that converts external electrical energy into chemical energy and stores it before generating electricity when needed. The name "rechargeable battery" is also used to mean that you can charge multiple times. Commonly used secondary batteries include lead-acid batteries, nickel-cadmium batteries (NiCd), nickel-metal hydride batteries (NiMH), lithium-ion batteries (Li-ion), and lithium-ion polymer batteries (Li-ion polymer). Secondary batteries offer both economic and environmental advantages over primary batteries that are used once and discarded.

Secondary batteries are currently used where low power is used. For example, there are devices, portable devices, tools, and uninterruptible power supplies that help start the car. The recent development of wireless communication technology has led to the popularization of portable devices, and there is also a tendency to wirelessize many types of conventional devices, and the demand for secondary batteries is exploding. In addition, hybrid vehicles and electric vehicles have been put into practical use in order to prevent environmental pollution, and these next-generation vehicles employ technology to reduce the value, weight, and increase the life of the vehicle by using a secondary battery.

In general, secondary batteries are mostly cylindrical, prismatic, or pouch-shaped batteries. This is because the secondary battery is manufactured by mounting an electrode assembly composed of a cathode, an anode, and a separator inside a pouch-shaped case of a cylindrical or square metal can or aluminum laminate sheet, and injecting electrolyte into the electrode assembly. Therefore, since a certain space for mounting the secondary battery is essential, the shape of the cylindrical, prismatic, or pouch-type of the secondary battery has a problem of acting as a limitation for the development of various types of portable devices. Accordingly, there is a demand for a new type of secondary battery that is easy to deform.

For these demands, a cable type secondary battery, which is a battery having a very large ratio of length to diameter of a cross-sectional area, has been proposed. Packaging for protecting such a cable-type secondary battery requires both flexibility and moisture barrier properties. When a tube packaging made of a general polymer material is used, moisture or air can be penetrated through the micropores of the polymer, contaminating the electrolyte inside the battery, thereby deteriorating battery performance.

To overcome this problem, a tubular pouch packaging made of metal foil can be used. When the battery is bent due to the stiff nature of the metal foil itself, it is not completely bent, but the surface of the metal foil must be bent or wrinkled, and eventually There may be problems such as tearing the metal foil.

Accordingly, a problem to be solved by the present invention is to provide a cable-type secondary battery that further improves flexibility of a battery and a method of manufacturing the same by using a sheet-shaped packaging formed by spirally winding around the outer surface of the cable-type electrode assembly.

In addition, another problem to be solved by the present invention is to provide a cable-type secondary battery having excellent moisture barrier properties and a method for manufacturing the same.

In order to solve the above problems, according to one aspect of the present invention, the inner electrode, the outer surface of the inner electrode is formed, and includes a separation layer to prevent short circuit of the electrode and an outer electrode formed around the separation layer Cable electrode assembly; And it is provided with a cable-type secondary battery including a sheet-shaped packaging formed by spirally wound around the outer surface of the cable-type electrode assembly.

At this time, the sheet-shaped packaging may be a strip structure extending in one direction.

Here, the sheet-shaped packaging may be formed by being spirally wound so as to overlap with each other, and in this case, the sheet-shaped packaging is spirally wound so that the width of the overlapping portions is within 0.5 times the packaging width of the sheet-like. Can be formed.

Meanwhile, the sheet-shaped packaging may include a moisture barrier film, a first sealant polymer layer formed on one surface of the moisture barrier film, and a second sealant polymer layer formed on the other surface of the moisture barrier film.

At this time, the first sealant polymer layer and the second sealant polymer layer may be formed of the same material.

In addition, the moisture barrier film may be a metal sheet or a polymer sheet, and the metal sheet may include iron (Fe), carbon (C), chromium (Cr), manganese (Mn), nickel (Ni), and copper ( Cu) and aluminum (Al) may include any one or two or more alloys selected from the group consisting of.

In addition, the polymer sheet may include any one or a mixture of two or more selected from the group consisting of a polyethylene sheet, a polypropylene sheet, a polymer clay composite, and a liquid crystal polymer sheet.

And, the first sealant polymer layer and the second sealant polymer layer are each independently, polypropylene-acrylic acid copolymer, polyethylene-acrylic acid copolymer, polypropylene chloride, polypropylene-butylene-ethylene terpolymer, polypropylene , Polyethylene and ethylene-propylene copolymer may include any one or a mixture of two or more selected from the group consisting of.

Meanwhile, the sheet-like packaging may further include a mechanical support layer formed between the moisture barrier film and the first sealant polymer layer, or between the moisture barrier film and the second sealant polymer layer.

Here, the mechanical support layer may be to include any one selected from the group consisting of polyester, polyamide, polyimide and polyolefin or a mixture of two or more of them.

On the other hand, the cable-type secondary battery may further include a heat-shrinkable tube surrounding the entire outer surface of the sheet-like packaging formed by winding the spiral.

In this case, the heat-shrinkable tube may include one or a mixture of two or more selected from the group consisting of polyolefin, polyester, fluororesin, and polyvinyl chloride.

In addition, an adhesive layer may be further included between the sheet-shaped packaging outer surface and the heat-shrinkable tube.

Meanwhile, the internal electrode includes a lithium ion supply core portion including an electrolyte, an internal current collector having an open structure formed surrounding an outer surface of the lithium ion supply core portion, and an internal electrode active material layer formed on the surface of the internal current collector. It may be.

At this time, the internal current collector of the open structure may be a wound wire-type current collector, a wound sheet-shaped current collector, or a mesh-type current collector.

In addition, the internal electrode and the external electrode may be a cathode and an anode, or may be an anode and a cathode, respectively.

Meanwhile, according to another aspect of the present invention, (S1) a cable type including an inner electrode, an outer layer formed around an outer surface of the inner electrode, and a separation layer preventing short circuit of the electrode and an outer electrode formed surrounding the separation layer Preparing an electrode assembly; (S2) spirally winding the sheet-shaped packaging on the outer surface of the cable-shaped electrode assembly, thereby forming to surround the outer surface of the cable-shaped electrode assembly; And (S3) after putting the result of the step (S2) into the sealing mold, and applying heat and pressure, there is provided a method of manufacturing a cable-type secondary battery comprising the step of sealing the result of the step (S2).

At this time, the (S2) step, the sheet-shaped packaging may be wound in a spiral to overlap each other.

According to the present invention, even when a strong external force such as bending is applied to the cable-type secondary battery, the sheet-shaped packaging formed by spirally winding on the outer surface of the cable-type secondary battery can disperse the external force, whereby the surface of the packaging is bent or Wrinkles can be prevented.

The following drawings attached to this specification are intended to illustrate preferred embodiments of the present invention, and serve to further understand the technical idea of the present invention together with the contents of the above-described invention, so the present invention is limited to those described in those drawings. It should not be construed as limited.
1 is a view schematically showing a state in which the sheet-shaped packaging is wound in a spiral around the outer surface of the cable-type electrode assembly according to an embodiment of the present invention.
2 is a view schematically showing a state in which the sheet-shaped packaging is wound in a spiral shape surrounding the outer surface of the cable-type electrode assembly according to another embodiment of the present invention.
3 is a view schematically showing a cross-section of a sheet-shaped packaging according to an embodiment of the present invention.
4 to 6 are views schematically showing cross-sections of sheet-shaped packaging according to another embodiment of the present invention.

Hereinafter, the present invention will be described in detail with reference to the drawings. The terms or words used in the specification and claims should not be interpreted as being limited to the ordinary or dictionary meanings, and the inventor can appropriately define the concept of terms in order to best describe his or her invention. Based on the principle that it should be interpreted as meanings and concepts consistent with the technical idea of the present invention.

Therefore, the configuration described in this specification is only one of the most preferred embodiments of the present invention and does not represent all of the technical spirit of the present invention, and there are various equivalents and modifications that can replace them at the time of application. It should be understood that it can.

1 and 2 is a view schematically showing a state in which the sheet-shaped packaging is wound in a spiral around the outer surface of the cable-type electrode assembly according to an embodiment of the present invention.

Referring to FIG. 1, according to an aspect of the present invention, a cable including an inner electrode, an outer layer formed around an outer surface of the inner electrode, and an outer layer formed surrounding the separation layer to prevent short circuit of the electrode Type electrode assembly 10; And it is provided with a cable-type secondary battery 100 including a sheet-shaped packaging 20 formed by being wound in a spiral around the outer surface of the cable-type electrode assembly (10).

When a tube packaging made of a general polymer material is used, moisture permeation is possible through micropores of the polymer, and contaminating the electrolyte inside the battery may cause deterioration of battery performance.

In order to overcome the problem of moisture penetration, it is possible to use tubular pouch packaging made of metal foil, even if the tubular pouch packaging of the metal foil is skin-tight formed in the cable-type electrode assembly, the electrode assembly and the pouch packaging Since a space exists between them and is not fixed to each other, when the battery is bent, wrinkles are generated on the pouch packaging surface. In other words, when the battery is bent, stress is applied to the internal electrode assembly as the pouch packaging is bent, and when this stress is accumulated, a micro short circuit is generated inside the battery, thereby allowing flexibility of the battery. Becomes vulnerable. Furthermore, fatigue may accumulate due to repeated bending in the wrinkles generated on the surface of the pouch packaging, and eventually the pouch packaging may tear.

However, if the sheet-like packaging is formed by spirally winding around the outer surface of the cable-type electrode assembly as described herein, even if the cable-type secondary battery is bent, the external force resulting therefrom can be dissipated, whereby the surface of the packaging is bent or wrinkled. It is possible to prevent the phenomenon from occurring.

Here, the spiral is expressed in spiral or helix in English, and is a shape twisted around a certain range, and generally refers to a shape similar to the shape of a general spring.

At this time, the sheet-shaped packaging may be a strip (strip, strip) structure extending in one direction.

1 shows a state in which the sheet-shaped packaging 20 does not overlap, and is wound and formed in a spiral form to be in close contact with each other, and FIG. 2 shows a state in which the sheet-shaped packaging 20 is formed in a spiral winding so as to overlap with each other. In this case, the sheet-shaped packaging 20 is spirally wound so that the width of the overlapping portions is within 0.5 times the packaging width of the sheet-shaped, so that the thickness of the cable-type secondary battery 100 is not too thick. Can be formed.

3 is a view schematically showing a cross-section of a sheet-shaped packaging according to an embodiment of the present invention.

Referring to Figure 3, the sheet-shaped packaging 20 of the present invention, the moisture barrier film 21, the first sealant polymer layer 23 formed on one surface of the moisture barrier film 21, and the moisture barrier The second sealant polymer layer 25 formed on the other surface of the sex film 21 may be provided.

Here, the moisture barrier film 21 serves to prevent moisture from penetrating from the outside to the inside, and may be selected from metal sheets or polymer sheets having moisture barrier properties.

The metal sheet having the moisture barrier property is a group consisting of iron (Fe), carbon (C), chromium (Cr), manganese (Mn), nickel (Ni), copper (Cu), aluminum (Al), and equivalents It may include any one or two or more alloys selected from. The metal sheet is not limited to the exemplified types, and the metal sheet has a higher mechanical strength when applying a material containing iron, and a better flexibility when applying a material containing aluminum.

In addition, the polymer sheet having moisture barrier properties may include one or a mixture of two or more selected from the group consisting of a polyethylene sheet, a polypropylene sheet, a polymer clay composite, and a liquid crystal polymer sheet.

The polymer clay composite means a composite in which a clay formed in a plate shape is dispersed in a polymer. Since the plate-shaped clay is arranged in the polymer, the pass way length through which gas or the like escapes is increased to suppress the passage of gas components, and the same principle can block moisture. In addition, the liquid crystal polymer sheet is a liquid crystal polymer (liquid crystal polymer) as the base material, the liquid crystal polymer is characterized in that the rigid segment (rigid segment) consisting of aromatic groups behaves similar to liquid crystals and these parts Like the clay of the polymer clay, it is possible to block the penetration of moisture by increasing the movement path.

In one embodiment of the present invention, the first sealant polymer layer 23 and the second sealant polymer layer 25 have heat-adhesive or heat-sealable properties that are adhered by heat, and are each independently polypropylene-acrylic acid Copolymers, polyethylene-acrylic acid copolymers, polypropylene chloride, polypropylene-butylene-ethylene terpolymers, polypropylene, polyethylene, and ethylene-propylene copolymers.

Here, the first sealant polymer layer 23 and the second sealant polymer layer 25 may be formed of the same material.

In this case, when the sheet-shaped packaging 20 of the present application is formed by being spirally wound so as to overlap with each other, the first sealant polymer layer 23 and the second sealant polymer layer 25 face each other in the overlapping portion. When heat or pressure is applied to this, since the first sealant polymer layer 23 and the second sealant polymer layer 25 are melted at the overlapping portion, complete sealing proceeds, thereby preventing moisture from penetrating into the battery. It can be prevented as effectively as possible.

4 to 6 are views schematically showing cross-sections of sheet-shaped packaging according to another embodiment of the present invention.

4 to 6, the sheet-shaped packaging 20 of the present invention further includes a mechanical support layer 27 formed between the moisture barrier film 21 and the first sealant polymer layer 23. Alternatively, a mechanical support layer 27 formed between the moisture barrier film 21 and the second sealant polymer layer 25 may be further included, and the moisture barrier film 21 and the first A mechanical support layer 27 formed between both the sealant polymer layer 23 and between the moisture barrier film 21 and the second sealant polymer layer 25 may be further included.

The mechanical support layer 27 serves to prevent the sheet-shaped packaging 20 from being torn or damaged against external stress or impact, and can be used without limitation as long as it has such a degree of mechanical properties. For example, the mechanical support layer 20 may include any one selected from the group consisting of polyester, polyamide, polyimide and polyolefin, or a mixture of two or more of them.

In addition, considering the low adhesion between the moisture barrier film 21, the sealant polymer layers 23 and 27, and the mechanical support layer 27, the moisture barrier film 21, the first sealant polymer layer (23), the mechanical support layer 27, and the second sealant polymer layer 25 may further include an adhesive layer between the layers facing each other. Through this, it is possible to further improve the adhesion properties and the moisture barrier properties. The material of the adhesive layer includes, for example, a composition containing a urethane-based material, an acrylic material, and a thermoplastic elastomer, but is not limited thereto.

The sheet-like packaging formed by winding the spiral may be used alone for packaging for a cable-type secondary battery, or may further include various types of polymers such as a polymer resin layer as the outer layer of the sheet-like packaging formed by winding the spiral.

Preferably, the outer layer may include a heat-shrinkable tube surrounding the entire outer surface of the sheet-like packaging formed by winding the spiral. The heat-shrinkable tube is a tube that contracts when heated, and means a material that tightly wraps a terminal or a material having a different shape or size. In the present invention, after the sheet-shaped packaging is spirally wound so as to surround the outer surface of the cable-type electrode assembly, when heat is applied after inserting it into the heat-shrinkable tube, the heat-shrinkable tube shrinks while being heated by heat transmitted through the heat-shrinkable tube. As a result, tight packaging can be provided by providing a tight gap between the sheet-shaped packaging surrounding the outer surface of the cable-type electrode assembly and the heat-shrinkable tube. Through tight and tight packaging, the moisture barrier performance of the packaging is further improved, and the effect of insulation can be obtained simultaneously through the heat shrink tube. In addition, when only the heat-shrinkable tube is used, there may be a phenomenon in which moisture is introduced into the battery due to the presence of pores in the structure of the heat-shrinkable tube. It was made to improve the flexibility and protect the battery sufficiently.

The heat-shrinkable tube is a heat-shrinkable tube having various materials and shapes, so it can be easily obtained and used for the purpose of the present invention. To avoid thermal damage of the secondary battery, it is necessary to lower the temperature of the shrinkage processing, generally 70 to 200, preferably 70 to 150, more preferably 100 to 150, and even more preferably 70 to The shrinkage is required to be completed at a temperature of 120. The heat-shrinkable tube is any one selected from the group consisting of polyolefins such as polyethylene and polypropylene, polyesters such as polyethylene terephthalate, fluororesins such as polyvinylidene fluoride and polytetrafluoroethylene, and polyvinyl chloride. Or a mixture of two or more of these.

At this time, in order to further improve the adhesion between the outer surface of the sheet-shaped packaging and the heat-shrinkable tube, an adhesive layer may be further included therebetween. Through this, it is possible to further improve the adhesion properties and the moisture barrier properties. The material of the adhesive layer includes, for example, a composition containing a urethane-based material, an acrylic material, and a thermoplastic elastomer, but is not limited thereto.

On the other hand, the cable-type secondary battery according to the present invention may have a horizontal cross section of a predetermined shape and extend in the longitudinal direction. Here, the predetermined shape means that the shape is not particularly limited, and damages the essence of the present invention. It means that any shape that is not done is possible. The horizontal cross-section of the predetermined shape may be circular or polygonal, and the circular structure is a geometrically complete symmetrical circular shape and an asymmetrical oval shape. The polygonal structure is not particularly limited, and non-limiting examples of such a polygonal structure may be triangular, square, pentagonal or hexagonal.

The cable-type secondary battery of the present invention has a horizontal cross-section of a predetermined shape, has a linear structure elongated in the longitudinal direction of the horizontal cross-section, has flexibility and is free from deformation.

In the present invention, the internal electrode, a lithium ion supply core portion including an electrolyte, an internal current collector having an open structure formed surrounding an outer surface of the lithium ion supply core portion, and an internal electrode active material layer formed on the surface of the internal current collector It may be provided.

The open structure refers to a structure in which the open structure is used as a boundary surface, and the material can be freely moved from inside to outside through the boundary surface.

The internal electrode according to an embodiment of the present invention includes a lithium ion supply core part including an electrolyte, and the internal electrode of the present invention has an open structure, so that the electrolyte of the lithium ion supply core part passes through the internal current collector of the open structure. By doing so, it is possible to reach the inner electrode active material layer and the outer electrode active material layer. Therefore, it is not necessary to force the thickness of the electrolyte layer excessively, but rather, since the electrolyte layer is not an essential component, only a separator may be selectively used. That is, the cable-type secondary battery having an open structure is provided with a lithium ion supply core portion containing an electrolyte, so that it can be easily penetrated into an electrode active material, and can easily supply lithium ions and exchange lithium ions at the electrode. Its capacity characteristics and cycle characteristics are excellent.

The lithium ion supply core portion includes an electrolyte, but the type of the electrolyte is not particularly limited, but ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), vinylene carbonate (VC), and di Ethyl carbonate (DEC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), methyl formate (MF), gamma-butyrolactone (γ-BL; butyrolactone), sulfolane, methyl acetate (MA non-aqueous electrolyte solution using methylacetate) or methylpropionate (MP); Gel polymer electrolytes using PEO, PVdF, PMMA, PAN or PVAC; Or a solid electrolyte using PEO, polypropylene oxide (PPO), polyethylene imine (PEI), polyethyle sulphide (PES) or polyvinyl acetate (PVAc); Etc. can be used. And, such an electrolyte may further include a lithium salt, such as a lithium salt, 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, chloro is preferred to use a borane lithium, lower aliphatic carboxylic acid lithium, and tetraphenyl lithium borate, etc. Do. In addition, the lithium ion supply core may be composed of only an electrolyte, and in the case of a liquid electrolyte, it may also be configured using a porous carrier.

The internal current collector of the present invention may have an open structure to facilitate the penetration of the electrolyte in the lithium ion supply core portion, and any of the open structures can be adopted as long as the structure has an easy penetration of the electrolyte. For example, a wound wire-type current collector, a wound sheet-type current collector, or a mesh-type current collector may be used.

The internal current collector is a surface treated with carbon, nickel, titanium, or silver on the surface of stainless steel, aluminum, nickel, titanium, calcined carbon, copper or stainless steel, an aluminum-cadmium alloy, and a surface treated with a conductive material. It is preferable to use a conductive polymer or a conductive polymer.

The current collector serves to collect electrons generated by the electrochemical reaction of the active material or to supply electrons necessary for the electrochemical reaction, and generally metals such as copper or aluminum are used. In particular, when a non-conductive polymer surface-treated with a conductive material or a polymer conductor made of a conductive polymer is used, it is relatively more flexible than a metal such as copper or aluminum. In addition, it is possible to achieve light weight of the battery by using a polymer current collector by replacing the metal current collector.

Examples of the conductive material include polyacetylene, polyaniline, polypyrrole, polythiophene and polysulfurnitride, ITO (Indum Thin Oxide), silver, palladium, and nickel, and conductive polymers include polyacetylene, polyaniline, polypyrrole, and polyti Offen and polysulfuride can be used. However, the non-conductive polymer used in the current collector is not particularly limited.

The inner electrode active material layer of the present invention may be formed on the surface of the inner current collector. At this time, it is formed around the outer surface of the inner current collector, as well as when the open structure of the inner current collector is not exposed to the outer surface of the inner electrode active material layer, the inner electrode active material layer is formed on the surface of the open structure of the inner current collector It also includes the case where the open structure of the inner current collector is exposed to the outer surface of the inner electrode active material layer. For example, a case where an active material layer is formed on the surface of a wound wire-type current collector and a case where a wire-type current collector having an electrode active material layer is wound is used.

The external current collector used for the external electrode of the present invention is not particularly limited, but a pipe-type current collector, a wound wire-type current collector, a wound sheet-type current collector, or a mesh-type current collector can be used. In addition, the external current collector includes stainless steel, aluminum, nickel, titanium, calcined carbon, and copper; Stainless steel surface-treated with carbon, nickel, titanium or silver; Aluminum-cadmium alloy; A non-conductive polymer surface-treated with a conductive material; Conductive polymers; A metal paste containing a metal powder which is Ni, Al, Au, Ag, Al, Pd/Ag, Cr, Ta, Cu, Ba or indium tin oxide (ITO); Alternatively, a carbon paste containing carbon powder that is graphite, carbon black, or carbon nanotubes may be used.

Meanwhile, a polymer support layer may be formed on the outer surface of the external electrode to improve flexibility of the external electrode and prevent detachment of the electrode active material layer. At this time, the material of the polymer support layer and the sealant polymer layer formed in the sheet-like packaging of the present application may be It may be made of the same material, and during the sealing process accompanied by heat or pressure, the external electrode and the sheet-like packaging are completely in contact, so that the battery may be more advantageously implemented in terms of flexibility.

The internal electrode may be a cathode or an anode, and the external electrode may be an anode or a cathode corresponding to the external electrode.

The electrode active material layer of the present invention functions to move ions through a current collector, and the movement of these ions is caused by interaction through absorption of ions from the electrolyte layer and release of ions to the electrolyte layer. The electrode active material layer is a negative electrode active material layer, natural graphite, artificial graphite, carbonaceous material; Lithium-containing titanium composite oxides (LTO), metals (Me) which are Si, Sn, Li, Zn, Mg, Cd, Ce, Ni, or Fe; Alloys composed of the metals (Me); Oxides (MeOx) of the metals (Me); And may include a complex of the metal (Me) and carbon, as a positive electrode active material layer LiCoO ₂ , LiNiO ₂ , LiMn ₂ O ₄ , LiCoPO ₄ , LiFePO ₄ , LiNiMnCoO ₂ And LiNi _{1 -xy- z} Co _x M1 _y M2 _z O ₂ (M1 and M2 are each independently selected from the group consisting of Al, Ni, Co, Fe, Mn, V, Cr, Ti, W, Ta, Mg and Mo, x, y and z Independently of each other, it is possible to use 0 ≤ x <0.5, 0 ≤ y <0.5, 0 ≤ z <0.5, 0 <x+y+z ≤ 1 as atomic fractions of oxide composition elements).

The separation layer of the present invention may use an electrolyte layer or a separator.

The electrolyte layer that serves as a channel for these ions is a gel polymer electrolyte using PEO, PVdF, PMMA, PAN or PVAc, or PEO, polypropylene oxide (PPO), polyethylene imine (PEI), polyethyle sulphide (PES) or polyvinyl acetate (PVAc). A solid electrolyte or the like is used. The matrix of the solid electrolyte is preferably a polymer or ceramic glass as the basic skeleton. In the case of a general polymer electrolyte, even if the ionic conductivity is satisfied, the ion can move very slowly in terms of reaction rate, so it is preferable to use a gel polymer electrolyte that is easier to move ions than in the case of a solid. Since the gel polymer electrolyte is not excellent in mechanical properties, a pore structure support or a crosslinked polymer may be included to compensate for this. Since the electrolyte layer of the present invention can function as a separator, a separate separator may not be used.

The electrolyte layer of the present invention may further include a lithium salt. Lithium salt may improve the ionic conductivity and reaction rate, and non-limiting examples of these include 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, chloro may borane lithium, lower aliphatic carboxylic acid lithium, and tetraphenyl lithium borate available .

The separator is not limited in its kind, but 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. materials; 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. Particularly, in order for lithium ions to be supplied to the lithium ion supply core part easily to the external electrode, the polyester, polyacetal, polyamide, polycarbonate, polyimide, polyether ether ketone, polyether sulfone, polyphenylene oxide, and polyphenylene It is preferable to use a separator made of a non-woven material corresponding to a porous substrate made of a polymer selected from the group consisting of sulfide and polyethylene naphthalate.

On the other hand, the method of manufacturing a cable-type secondary battery according to an aspect of the present invention,

(S1) preparing a cable-type electrode assembly including an inner electrode, an outer layer formed around the outer surface of the inner electrode, and a outer layer formed around the separation layer to prevent a short circuit of the electrode;

(S2) spirally winding the sheet-shaped packaging on the outer surface of the cable-shaped electrode assembly, thereby forming to surround the outer surface of the cable-shaped electrode assembly; And

(S3) after putting the result of the step (S2) into the sealing mold, and applying heat and pressure, sealing the result of the step (S2).

Since the sealing mold has a groove corresponding to the cable-type secondary battery and a heating wire inside the sealing mold, when the cable-type secondary battery is introduced into the sealing mold, the electrode assembly and the sheet-shaped packaging are brought into close contact with each other. , Sealant polymer layers melt and adhere to each other, thereby helping to seal the electrode assembly in a skin-tight manner.

At this time, the (S2) step, the sheet-shaped packaging may be wound in a spiral to overlap each other. Accordingly, even if a strong bending external force acts on the cable-type secondary battery, it is possible to prevent the gap between the sheet-shaped packaging from opening.

On the other hand, the embodiments of the present invention disclosed in the 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 is apparent to those skilled 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: cable type electrode assembly
20: Sheet-shaped packaging
21: moisture barrier film
23: first sealant polymer layer
25: second sealant polymer layer
27: mechanical support layer
100: cable type secondary battery

Claims (20)

A cable-type electrode assembly including an internal electrode, an outer layer formed around the outer surface of the inner electrode, and a separation layer preventing short-circuiting of the electrode and an outer electrode formed surrounding the separation layer; And
It includes a sheet-like packaging formed in a spiral wound around the outer surface of the cable-type electrode assembly,
The sheet-shaped packaging is a strip structure extending in one direction,
The sheet-shaped packaging is formed by being wound in a spiral to overlap each other,
The sheet-shaped packaging includes a moisture barrier film, a first sealant polymer layer formed on one surface of the moisture barrier film, and a second sealant polymer layer formed on the other surface of the moisture barrier film,
The first sealant polymer layer and the second sealant polymer layer are formed of the same material as each other,
When the sheet-shaped packaging is formed by spirally winding to overlap each other, the first sealant polymer layer and the second sealant polymer layer face each other in the overlapping portion, and the first sealant polymer layer in the overlapping portion. A cable-type secondary battery, characterized in that the second sealant polymer layer is melted and sealed.
delete delete According to claim 1,
The sheet-shaped packaging, the cable-type secondary battery, characterized in that the width of the overlapping portion formed by spirally wound within 0.5 times of the packaging width of the sheet-like.
delete delete According to claim 1,
The moisture barrier film is a cable-type secondary battery, characterized in that a metal sheet or a polymer sheet. The method of claim 7,
The metal sheet is any one or two selected from the group consisting of iron (Fe), carbon (C), chromium (Cr), manganese (Mn), nickel (Ni), copper (Cu), and aluminum (Al). A cable type secondary battery comprising the above alloy. The method of claim 7,
The polymer sheet is a cable-type secondary battery, characterized in that it comprises any one or two or more mixtures selected from the group consisting of a polyethylene-based sheet, a polypropylene-based sheet, a polymer clay composite and a liquid crystal polymer sheet. According to claim 1,
The first sealant polymer layer and the second sealant polymer layer are each independently polypropylene-acrylic acid copolymer, polyethylene-acrylic acid copolymer, polypropylene chloride, polypropylene-butylene-ethylene terpolymer, polypropylene, polyethylene And a mixture of at least one or two or more selected from the group consisting of ethylene-propylene copolymers. According to claim 1,
The sheet-like packaging further comprises a mechanical support layer formed between the moisture barrier film and the first sealant polymer layer, or between the moisture barrier film and the second sealant polymer layer. Secondary battery. The method of claim 11,
The mechanical support layer, a cable-type secondary battery comprising any one or a mixture of two or more selected from the group consisting of polyester, polyamide, polyimide and polyolefin. According to claim 1,
A cable-type secondary battery further comprising a heat-shrinkable tube surrounding the entire outer surface of the sheet-like packaging formed by the spiral winding. The method of claim 13,
The heat-shrinkable tube, a cable-type secondary battery, characterized in that it comprises any one or a mixture of two or more selected from the group consisting of polyolefin, polyester, fluororesin and polyvinyl chloride. The method of claim 13,
A cable-type secondary battery further comprising an adhesive layer between the sheet-shaped packaging outer surface and the heat-shrinkable tube. According to claim 1,
The internal electrode includes a lithium ion supply core portion including an electrolyte, an internal current collector having an open structure formed surrounding an outer surface of the lithium ion supply core portion, and an internal electrode active material layer formed on a surface of the internal current collector. Cable type secondary battery characterized by. The method of claim 16,
The inner current collector of the open structure, the cable-type secondary battery, characterized in that the wound wire-type current collector, a wound sheet-shaped current collector or a mesh-type current collector. According to claim 1,
The inner electrode and the outer electrode, respectively, a cathode and a positive electrode or a cable-type secondary battery, characterized in that the anode and the cathode. (S1) preparing a cable-type electrode assembly including an inner electrode, an outer layer formed around the outer surface of the inner electrode, and a outer layer formed around the separation layer to prevent a short circuit of the electrode;
(S2) spirally winding the sheet-shaped packaging on the outer surface of the cable-shaped electrode assembly, thereby forming to surround the outer surface of the cable-shaped electrode assembly; And
(S3) after putting the result of the step (S2) into the sealing mold, and applying heat and pressure, sealing the result of the step (S2),
In the step (S2), the sheet-shaped packaging is spirally wound so as to overlap each other,
The sheet-shaped packaging is a strip structure extending in one direction,
The sheet-shaped packaging is formed by being wound in a spiral to overlap each other,
The sheet-shaped packaging includes a moisture barrier film, a first sealant polymer layer formed on one surface of the moisture barrier film, and a second sealant polymer layer formed on the other surface of the moisture barrier film,
The first sealant polymer layer and the second sealant polymer layer are formed of the same material as each other,
When the sheet-shaped packaging is formed by spirally winding to overlap each other, the first sealant polymer layer and the second sealant polymer layer face each other in the overlapping portion, and the first sealant polymer layer in the overlapping portion. A method of manufacturing a cable-type secondary battery, characterized in that the second sealant polymer layer is melted and sealed.
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