CN104393231A - Electrode for secondary battery, preparation thereof, and secondary battery and cable-type secondary battery comprising the same - Google Patents

Abstract

The invention relates to an electrode for a secondary battery, preparation thereof, and a secondary battery and a cable-type secondary battery comprising the same. The electrode for a secondary battery, comprising a current collector; an electrode active material layer formed on one surface of the current collector; a porous polymer layer formed on the electrode active material layer; and a first porous supporting layer formed on the porous polymer layer. The sheet-form electrode for a secondary battery according to the present disclosure has supporting layers on at least one of surfaces thereof to exhibit surprisingly improved flexibility and prevent the release of the electrode active material layer from a current collector even if intense external forces are applied to the electrode, thereby preventing the decrease of battery capacity and improving the cycle life characteristic of the battery.

Description

Electrode for secondary battery, preparation thereof, secondary battery and cable-type secondary battery comprising same

Cross References to Related Applications

This application claims priority from Korean Patent Application No. 10-2013-0051566 filed in Korea on May 7, 2013, the contents of which are incorporated herein by reference.

technical field

The present invention relates to an electrode for a secondary battery, and more particularly, to an electrode for a secondary battery capable of preventing an electrode active material layer from coming off and having improved flexibility, a method for producing the electrode, and a secondary battery including the electrode and a cable-type secondary battery.

Background technique

A secondary battery is a device capable of storing energy in a chemical form and converting it into electrical energy to generate electricity when needed. A secondary battery is also called a rechargeable battery because it can be repeatedly recharged. Common secondary batteries include lead storage batteries, NiCd batteries, NiMH storage batteries, Li ion batteries, Li ion polymer batteries, and the like. Secondary batteries are not only more cost-effective but also more environmentally friendly when compared to disposable primary batteries.

Secondary batteries are currently used in applications requiring low power, such as equipment for starting vehicles, mobile devices, tools, uninterruptible power supplies, and the like. Recently, as the development of wireless communication technology leads to the spread of mobile devices, and even to the mobilization of various conventional devices, the demand for secondary batteries has increased dramatically. Secondary batteries are also used in environmentally friendly next-generation vehicles such as hybrid vehicles and electric vehicles to reduce cost and weight and increase the service life of the vehicles.

Generally, secondary batteries have a cylindrical, prismatic or pouch shape. This is related to a manufacturing method of a secondary battery in which an electrode assembly consisting of a negative electrode, a positive electrode, and a separator is installed in a cylindrical or prismatic metal case or a pouch-shaped case of an aluminum laminate sheet, and the electrolyte is used to fill the Said shell. Since a predetermined installation space for the electrode assembly is necessary in this method, the cylindrical, prismatic, or pouch shape of the secondary battery is a limitation in developing mobile devices of various shapes. Therefore, there is a need for a secondary battery having a new structure whose shape is easily adaptable.

In order to meet this need, it has been proposed to develop a cable-type battery having a very large ratio of length to cross-sectional diameter. The cable-type battery is prone to change in shape while undergoing stress due to an external force causing the change in shape. In addition, the electrode active material layer of the cable-type battery may be peeled off due to rapid volume expansion during the charging and discharging process. According to these reasons, the capacity of the battery may decrease and its cycle life characteristics may deteriorate.

This problem can be solved to some extent by increasing the amount of binder used in the electrode active material layer to provide flexibility during bending or twisting. However, increasing the amount of the binder in the electrode active material layer causes an increase in electrode resistance to degrade battery performance. In addition, when a strong external force is applied, for example, in the case of completely folding the electrode, even if the amount of the binder becomes large, the electrode active material layer cannot be prevented from coming off. Therefore, this method is insufficient to solve this kind of problem.

Contents of the invention

The present invention has been devised to solve the problems of the related art, and thus, the present invention relates to providing an electrode for a secondary battery, a method for preparing the electrode, and a secondary battery and a cable-type secondary battery including the electrode, so that The electrode for a secondary battery can reduce the generation of cracks in the electrode active material layer caused by external force, and can prevent the electrode active material layer from falling off from the current collector even if there are severe cracks.

According to an aspect of the present invention, there is provided a sheet-form electrode for a secondary battery, comprising: a current collector; an electrode active material layer formed on one surface of the current collector; a porous polymer layer formed on the current collector. On the electrode active material layer; a first porous support layer formed on the porous polymer layer.

The current collector may be made of: stainless steel, aluminum, nickel, titanium, sintered carbon or copper; stainless steel treated with carbon, nickel, titanium or silver on its surface; aluminum-cadmium alloy; Non-conductive polymers treated with conductive materials; conductive polymers; metal pastes containing metal powders of Ni, Al, Au, Ag, Pd/Ag, Cr, Ta, _Cu , Ba or ITO; or containing graphite, carbon Carbon paste of black or carbon nanotube carbon powder.

In addition, the current collector may be in the form of mesh.

In addition, the current collector may further include an undercoat layer composed of a conductive material and a binder.

The conductive material may comprise any one selected from the group consisting of carbon black, acetylene black, Ketjen black, carbon fiber, carbon nanotube, graphene and mixtures thereof.

The binder may be selected from polyvinylidene fluoride (PVDF), polyvinylidene fluoride-co-hexafluoropropylene, polyvinylidene fluoride-co-trichloroethylene, polybutylacrylate, polymethacrylic acid Methyl ester, polyacrylonitrile, polyvinylpyrrolidone, polyvinyl acetate, polyethylene-co-vinyl acetate, polyethylene oxide, polyarylate, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate cyanoethyl pullulan, cyanoethyl polyvinyl alcohol, cyanoethyl cellulose, cyanoethyl sucrose, pullulan, carboxymethyl cellulose, styrene-butadiene rubber, acrylonitrile-styrene-butadiene Copolymers, polyimides and their blends.

In addition, the current collector may have a plurality of recesses.

The plurality of recesses are continuously patterned or discontinuously patterned on at least one surface thereof.

Meanwhile, the first support layer may be a mesh-shaped porous film or non-woven fabric.

The first support layer can be made of any one selected from the following: high-density polyethylene, low-density polyethylene, linear low-density polyethylene, ultra-high molecular weight polyethylene, polypropylene, polyethylene terephthalate Alcohol ester, polybutylene terephthalate, polyester, polyacetal, polyamide, polycarbonate, polyimide, polyetheretherketone, polyethersulfone, polyphenylene ether, polyphenylene sulfide, Polyethylene naphthalate and mixtures thereof.

In addition, the first support layer may further comprise a conductive material coating having a conductive material and a binder on its surface.

In the conductive material coating, the conductive material and the binder may exist in a weight ratio of 80:20˜99:1.

The conductive material may comprise any one selected from the following: carbon black, acetylene black, Ketjen black, carbon fiber, carbon nanotube, graphene and mixtures thereof.

Meanwhile, the porous polymer layer may have a pore diameter of 0.01˜10 μm and a porosity of 5˜95%.

The porous polymer layer may include a linear polymer having polarity, an oxide-based linear polymer, or a mixture thereof.

The polar linear polymer can be selected from: polyacrylonitrile, polyvinyl chloride, polyvinylidene fluoride (PVDF), polyvinylidene fluoride-co-hexafluoropropylene, polyvinylidene fluoride-co- Trichlorethylene, polyethyleneimine, polymethylmethacrylate, polybutylacrylate, polyvinylpyrrolidone, polyvinyl acetate, polyethylene-co-vinyl acetate, polyarylate, polyterephthaloyl p-Phenylenediamine and mixtures thereof.

The oxide-based linear polymer may be selected from polyethylene oxide, polypropylene oxide, polyoxymethylene, polydimethylsiloxane and mixtures thereof.

Meanwhile, the electrode for a secondary battery may further include a porous coating layer formed of a mixture of inorganic particles and a binder polymer on the first porous support layer.

In addition, the electrode for a secondary battery may further include a second support layer formed on the other surface of the current collector.

The second support layer may be a polymer film. The polymer film can be made from polyolefins, polyesters, polyimides, polyamides and mixtures thereof.

Meanwhile, when the electrode for a secondary battery is used as a negative electrode, the electrode active material layer may contain an active material selected from natural graphite, artificial graphite, or carbonaceous material; lithium-titanium composite oxide (LTO) , and metals (Me) including Si, Sn, Li, Zn, Mg, Cd, Ce, Ni, and Fe; alloys of said metals; oxides (MeOx) of said metals; complexes of said metals and carbon and mixtures thereof, and when the electrode for a secondary battery is used as a positive electrode, the electrode active material layer may contain an active material selected from the group consisting of: LiCoO ₂ , LiNiO ₂ , LiMn ₂ O ₄ , LiCoPO ₄ , LiFePO ₄ , LiNiMnCoO ₂ , LiNi _1-xyz Co _x M1 _y M2 _z O ₂ (where M1 and M2 are each independently selected from: Al, Ni, Co, Fe, Mn, V, Cr, Ti, W, Ta, Mg and Mo, and x, y, and z are each independently an atomic fraction of an oxide-forming element, where 0≤x<0.5, 0≤y<0.5, 0≤z<0.5, and x+y+z≤1) and mixtures thereof.

According to another aspect of the present invention, there is provided a method for preparing an electrode for a secondary battery in the form of a sheet, comprising: (S1) coating a slurry containing an electrode active material on one surface of a current collector, followed by drying, thereby Forming an electrode active material layer; (S2) coating a polymer solution containing a polymer on the electrode active material layer; (S3) forming a first porous support layer on the polymer solution; and (S4) The product obtained in step (S3) is compressed to form a porous polymer layer bonded between the electrode active material layer and the first porous support layer to be integrated with each other.

The polymer solution may contain a binder component.

Here, in the step (S3), the first porous support layer may be formed on the polymer solution before the binder component is cured.

In addition, in the step (S4), the preparation obtained in the step (S3) may be compressed by a coating blade to form a porous polymer layer adhered to the electrode active material layer. integrated with the first porous support layer.

In addition, the method may further include forming a second support layer by compressing on the other surface of the current collector before the step (S1) or after the step (S4).

Furthermore, according to still another aspect of the present invention, there is provided a cable-type secondary battery including: an inner electrode; a separator surrounding an outer surface of the inner electrode to prevent a short circuit between the electrodes; and an outer electrode, It is formed by being spirally wound so as to surround the outer surface of the separator, wherein at least one of the inner electrode and the outer electrode is formed by using the above-mentioned electrode for a secondary battery according to the present invention.

Here, the external electrodes may be formed in the form of uniaxially extended strips.

In addition, the external electrodes may be helically wound so as not to overlap or to overlap in width thereof.

In addition, the internal electrode may be a hollow structure in which a central portion is hollow.

Here, the internal electrode may include one or more electrodes for a secondary battery wound in a spiral shape.

The internal electrode may be provided therein with a core of an internal current collector, a core for supplying lithium ions, which contains an electrolyte, or a filled core.

The core for supplying lithium ions may include a gel polymer electrolyte and a support, or may include a liquid electrolyte and a porous carrier.

The electrolyte used in the core for supplying lithium ions may be selected from the group consisting of 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), γ-butyrolactone (γ-BL), sulfolane, methyl acetate (MA) or methyl propionate (MP); gel polymer electrolytes using PEO, PVdF, PVdF-HFP, PMMA, PAN, or PVAc; and using PEO, polypropylene oxide (PPO), polyethylene A solid electrolyte of amine (PEI, polyether imine), polyethyl sulfide (PES) or polyvinyl acetate (PVAc).

The electrolyte may further comprise a lithium salt, and the lithium salt may be selected from: 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, lower aliphatic lithium carbonate, lithium tetraphenylborate and mixtures thereof.

The internal electrode may be a negative electrode or a positive electrode, and the external electrode may be a positive electrode or a negative electrode corresponding to the internal electrode.

Meanwhile, the isolation layer may be an electrolyte layer or a diaphragm.

The electrolyte layer may contain an electrolyte selected from the group consisting of gel polymer electrolytes using PEO, PVdF, PMMA, PVdF-HFP, PAN, or PVAc; and using PEO, polypropylene oxide (PPO), polyethyleneimine ( PEI), polyethylene sulfide (PES) or polyvinyl acetate (PVAc) solid electrolytes.

The electrolyte layer may further comprise a lithium salt, and the lithium salt may be selected from: 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, lower aliphatic lithium carbonate, lithium tetraphenylborate and mixtures thereof.

The separator may be: made of a polyolefin polymer selected from the group consisting of ethylene homopolymer, propylene homopolymer, ethylene-butene copolymer, ethylene-hexene copolymer and ethylene-methacrylate copolymer A porous polymer substrate; made of polyester, polyacetal, polyamide, polycarbonate, polyimide, polyetheretherketone, polyethersulfone, polyphenylene ether, polyphenylene sulfide and polynaphthalene A porous polymer substrate made of a polymer in ethylene glycol formate; a porous substrate made of a mixture of inorganic particles and a binder polymer; or a separator having A porous coating on at least one surface of a material and comprising inorganic particles and a binder polymer.

In addition, according to still another aspect of the present invention, there is provided a cable-type secondary battery, including:

A core for supplying lithium ions, which contains an electrolyte;

an inner electrode surrounding an outer surface of the core for supplying lithium ions, and comprising a current collector and an electrode active material layer;

an isolation layer surrounding the outer surface of the inner electrode to prevent short circuits between the electrodes; and

An external electrode formed by being wound in a helical shape so as to surround the outer surface of the separator, and comprising a current collector and an electrode active material layer, wherein at least one of the internal electrode and the external electrode is used according to The above-mentioned secondary battery of the present invention is formed using an electrode.

In addition, according to still another aspect of the present invention, there is provided a cable-type secondary battery, including:

Two or more internal electrodes arranged parallel to each other;

an isolation layer surrounding the outer surfaces of the inner electrodes to prevent short circuits between the electrodes; and

An external electrode formed by being spirally wound so as to surround the outer surface of the separator, wherein at least one of the internal electrode and the external electrode is formed using the above-mentioned electrode for a secondary battery according to the present invention Forming.

In addition, according to still another aspect of the present invention, there is provided a cable-type secondary battery comprising: two or more cores for supplying lithium ions containing an electrolyte; two or more internal electrodes arranged in parallel to each other, Each inner electrode surrounds the outer surface of each core for supplying lithium ions and includes a current collector and an electrode active material layer; a separation layer surrounds the outer surface of the inner electrode to prevent short circuit between the electrodes; and an outer electrode, which It is formed by winding in a helical shape so as to surround the outer surface of the separator, and contains a current collector and an electrode active material layer, wherein at least one of the inner electrode and the outer electrode is formed using the above-mentioned electrode according to the present invention. Formed with electrodes for secondary batteries.

Here, the internal electrode may include one or more electrodes for a secondary battery wound in a spiral shape.

Thus, the electrode for secondary batteries in the form of a sheet according to the invention has a support layer on at least one surface thereof, thereby exhibiting surprisingly improved flexibility.

When a strong external force is applied to the electrode, such as during complete folding of the electrode, the support layer acts as a buffer, thereby reducing the amount of binder in the electrode active material layer even if the amount of the binder in the electrode active material layer does not increase. Cracks occur. Thereby, the electrode active material layer can be prevented from coming off from the current collector.

Therefore, the electrode in the form of a sheet can prevent a decrease in battery capacity and can improve cycle life characteristics of the battery.

In addition, an electrode in the form of a sheet has a porous polymer layer on the top surface of its electrode active material layer so that an electrolytic solution can be well introduced into the electrode active material layer, thereby suppressing an increase in the resistance of the electrode.

In addition, since the porous support layer is provided, the electrolytic solution can penetrate into the pores of the porous support layer to suppress an increase in the resistance of the battery, thereby preventing battery performance from deteriorating.

Description of drawings

The accompanying drawings show preferred embodiments of the present invention, and are used together with the above-mentioned content of the invention to further understand the technical gist of the present invention. However, the present invention should not be construed as being limited to the accompanying drawings.

FIG. 1 shows a cross section of an electrode for a secondary battery in the form of a sheet according to one embodiment of the present invention.

FIG. 2 shows a cross-section of a sheet-form electrode for a secondary battery according to another embodiment of the present invention.

FIG. 3 schematically shows a method of preparing an electrode for a secondary battery in sheet form according to one embodiment of the present invention.

Fig. 4 shows the surface of a current collector in the form of a mesh according to one embodiment of the present invention.

Fig. 5 schematically shows the surface of a current collector with a plurality of recesses according to one embodiment of the present invention.

FIG. 6 schematically shows the surface of a current collector having a plurality of recesses according to another embodiment of the present invention.

Fig. 7 is a photograph showing a cross section of a porous polymer layer obtained by one embodiment of the present invention.

FIG. 8 schematically shows an internal electrode in the form of a sheet wound on the outer surface of the core for supplying lithium ions in the cable-type secondary battery of the present invention.

FIG. 9 is an exploded perspective view schematically showing the inside of a cable-type secondary battery according to an embodiment of the present invention.

FIG. 10 schematically shows a cross-section of a cable-type secondary battery having a plurality of internal electrodes according to the present invention.

<reference sign>

10: Current collector 20: Electrode active material layer

30: porous polymer layer 30': polymer solution

40: First support layer 50: Second support layer

60: coating scraper

100, 200: cable type secondary battery

110, 210: core for supplying lithium ions

120, 220: inner collector

130, 230: inner electrode active material layer

140, 240: porous polymer layer

150, 250: the first support layer

160, 260: second support layer

170, 270: isolation layer

180, 280: outer electrode active material layer

190, 290: Outer collector

195, 295: protective coating

Detailed ways

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Before proceeding to the specification, it should be understood that the terms used in the specification and appended claims should not be construed as being limited to their ordinary and dictionary meanings, but rather should be used to allow the inventors to define the terms appropriately for the best The terms are interpreted according to the meanings and concepts corresponding to the technical aspects of the present invention on the basis of the principle of explanation.

Accordingly, the descriptions set forth herein are preferred examples for illustrative purposes only and are not intended to limit the scope of the invention, so that it should be understood that other equivalents can be made thereto without departing from the spirit and scope of the invention. and variants.

1 and 2 show cross-sections of a sheet-form electrode for a secondary battery according to one embodiment of the present invention, and FIG. 3 schematically shows a preferred method of preparing the sheet-form electrode for a secondary battery according to one embodiment of the present invention.

Referring to FIGS. 1-3 , an electrode for a secondary battery in sheet form according to the present invention includes: a current collector 10; an electrode active material layer 20 formed on one surface of the current collector 10; A porous polymer layer 30 on top of the porous polymer layer 30; and a first porous support layer 40 formed on the top surface of the porous polymer layer 30.

And, the electrode for a secondary battery in sheet form according to the present invention may further include a second support layer 50 formed on the other surface of the current collector 10 .

In order for the battery to be flexible, the electrodes used in the battery should be sufficiently flexible. However, in the case of a conventional cable-type battery as an example of a flexible battery, the electrode active material layer is prone to stress caused by an external force causing shape change, or when a high-capacity negative electrode active material containing Si, Sn, etc. is used. It is shed by its rapid volume expansion during the charging and discharging process. Such exfoliation of the electrode active material layer reduces the capacity of the battery and deteriorates cycle life characteristics. As an attempt to overcome this problem, the amount of binder in the electrode active material layer has been increased to provide flexibility during bending or twisting.

However, increasing the amount of the binder in the electrode active material layer causes an increase in electrode resistance to degrade battery performance. In addition, when a strong external force is applied, such as in the case of completely folding the electrode, even if the amount of the binder becomes large, the electrode active material layer cannot be prevented from coming off. Therefore, this method is insufficient to solve this kind of problem.

In order to overcome the above-mentioned problems, the present inventors designed a two-stage support layer in the form of a sheet by including a first support layer 40 formed on its outer surface and a second support layer 50 optionally further formed on the other surface of the current collector 10. Electrodes for secondary batteries.

That is, even if the electrode is subjected to an external force during bending or twisting, the first support layer 40 having porosity acts as a buffer capable of relieving the external force applied to the electrode active material layer 20, thereby preventing the electrode active material layer 20 from coming off, thereby improving Electrode flexibility. In addition, when the second support layer 50 is further formed, short circuit of the current collector 10 can be suppressed, thereby further improving the flexibility of the electrode.

In addition, the electrode of the present invention includes a porous polymer layer 30 as an adhesive for bonding the first porous support layer 40 and the electrode active material layer to integrate them with each other, and the porous polymer layer 30 is formed by binding the polymer The solution is obtained by drying.

If a general adhesive is used as the adhesive, it acts as a resistance to the electrodes to degrade battery performance. On the contrary, the porous polymer layer 30 having a porous structure makes it possible to well introduce the electrolytic solution into the electrode active material layer, thereby suppressing an increase in electrode resistance.

Hereinafter, a method of manufacturing an electrode for a secondary battery in the form of a sheet will be described with reference to FIGS. 1-3 . Although a case where the second support layer 50 is first formed under the current collector 10 and then the porous polymer layer is formed in FIG. 3 is shown, this is only one embodiment of the present invention. Therefore, as mentioned below, the porous polymer layer may be formed without forming the second support layer.

First, the electrode active material layer 20 is formed by applying an electrode active material-containing slurry on one surface of the current collector 10, followed by drying (S1).

The current collector 10 may be made of: stainless steel, aluminum, nickel, titanium, sintered carbon or copper; stainless steel treated with carbon, nickel, titanium or silver on its surface; aluminum-cadmium alloy; Non-conductive polymers treated with conductive materials; conductive polymers; metal pastes containing metal powders of Ni, Al, Au, Ag, Pd/Ag, Cr, Ta, Cu, Ba or ITO; or containing graphite, carbon Carbon paste of black or carbon nanotube carbon powder.

As described above, when the secondary battery experiences external force due to bending or twisting, the electrode active material layer may fall off from the current collector. For this reason, a large amount of binder components are used in the electrode active material layer to provide flexibility in the electrode. However, a large amount of adhesive may be easily peeled off due to swelling caused by the electrolyte, thereby deteriorating battery performance.

Therefore, in order to improve the adhesiveness between the electrode active material layer and the current collector, the current collector 10 may further include an undercoat layer composed of a conductive material and a binder.

The conductive material may include any one selected from the following: carbon black, acetylene black, Ketjen black, carbon fiber, carbon nanotube, graphene and mixtures thereof, but not limited thereto.

The binder may be selected from: polyvinylidene fluoride (PVDF), polyvinylidene fluoride-co-hexafluoropropylene, polyvinylidene fluoride-co-trichloroethylene, polybutyl acrylate, polymethyl Methyl acrylate, polyacrylonitrile, polyvinylpyrrolidone, polyvinyl acetate, polyethylene-co-vinyl acetate, polyethylene oxide, polyarylate, cellulose acetate, cellulose acetate butyrate, acetate propionate Cellulose, cyanoethyl pullulan, cyanoethyl polyvinyl alcohol, cyanoethyl cellulose, cyanoethyl sucrose, pullulan, carboxymethyl cellulose, styrene-butadiene rubber, acrylonitrile-styrene-butane ethylene copolymers, polyimides, and mixtures thereof, but are not limited thereto.

In addition, referring to FIGS. 4-6 , the current collector 10 may be in the form of a mesh, and may have a plurality of recesses on at least one surface thereof, thereby further increasing its surface area. The recesses may be continuously patterned or discontinuously patterned. That is, continuously patterned recesses may be formed spaced apart from each other in the longitudinal direction, or a plurality of holes may be formed in an intermittent pattern. The plurality of holes may be circular or polygonal.

In the present invention, when the electrode for a secondary battery is used as a negative electrode, the electrode active material layer may contain an active material selected from the following: natural graphite, artificial graphite or carbonaceous material; lithium-titanium composite oxide (LTO ), and metals (Me) including Si, Sn, Li, Zn, Mg, Cd, Ce, Ni, and Fe; alloys of said metals; oxides (MeOx) of said metals; composites of said metals and carbon and mixtures thereof, and when the secondary battery electrode is used as a positive electrode, the electrode active material layer may contain an active material selected from LiCoO ₂ , LiNiO ₂ , LiMn ₂ O ₄ , LiCoPO ₄ , LiFePO _4. LiNiMnCoO ₂ , LiNi _1-xyz Co _x M1 _y M2 _z O ₂ (wherein M1 and M2 are each independently selected from: Al, Ni, Co, Fe, Mn, V, Cr, Ti, W, Ta, Mg and Mo, and x, y, and z are each independently an atomic fraction of an oxide-forming element, where 0≤x<0.5, 0≤y<0.5, 0≤z<0.5, and x+y+z≤1) and its mixture.

Then, a polymer-containing polymer solution 30' is coated on the electrode active material layer 20 (S2).

The polymer may be a polar linear polymer, an oxide-based linear polymer or a mixture thereof.

The polar linear polymer can be selected from: polyacrylonitrile, polyvinyl chloride, polyvinylidene fluoride (PVDF), polyvinylidene fluoride-co-hexafluoropropylene, polyvinylidene fluoride-co- Trichlorethylene, polyethyleneimine, polymethylmethacrylate, polybutylacrylate, polyvinylpyrrolidone, polyvinyl acetate, polyethylene-co-vinyl acetate, polyarylate, polyterephthaloyl p-Phenylenediamine and mixtures thereof.

The oxide-based linear polymer may be selected from polyethylene oxide, polypropylene oxide, polyoxymethylene, polydimethylsiloxane and mixtures thereof.

Then, a first porous support layer 40 is formed on the applied polymer solution (30) (S3).

Meanwhile, the first supporting layer 40 may be a mesh-shaped porous film or non-woven fabric. This porous structure makes it possible to introduce the electrolyte well into the electrode active material layer 20, and the first support layer 40 itself has excellent electrolyte impregnation to provide good ion conductivity, thereby preventing the electrode resistance from increasing. And ultimately prevent battery performance from deteriorating.

The first support layer 40 can be made of any one selected from the following: high-density polyethylene, low-density polyethylene, linear low-density polyethylene, ultra-high molecular weight polyethylene, polypropylene, polyethylene terephthalate Glycol ester, polybutylene terephthalate, polyester, polyacetal, polyamide, polycarbonate, polyimide, polyetheretherketone, polyethersulfone, polyphenylene ether, polyphenylene sulfide , polyethylene naphthalate and mixtures thereof.

In addition, the first support layer 40 may further include a conductive material coating with a conductive material and an adhesive on the first support layer 40 . The conductive material coating serves to increase the conductivity of the electrode active material layer and reduce electrode resistance, thereby preventing battery performance from deteriorating.

The conductive material and binder used in the conductive material coating may be the same as those used in the primer layer described above.

Such a conductive material coating is more advantageous when applied to a positive electrode than when applied to a negative electrode, because the low conductivity of the positive electrode active material layer enhances performance degradation caused by an increase in electrode resistance, and the negative electrode active material layer has a relatively Good electrical conductivity, thus showing similar performance to conventional negative electrodes due to being less affected by the coating of conductive material.

In the conductive material coating, the conductive material and the binder may exist in a weight ratio of 80:20˜99:1. Using large amounts of binder can cause a severe increase in electrode resistance. Therefore, when such a numerical range is satisfied, the electrode resistance can be prevented from being severely increased. In addition, as described above, since the first support layer acts as a buffer capable of preventing the electrode active material layer from coming off, the use of a binder in a relatively small amount does not greatly affect electrode flexibility.

Subsequently, the preparation obtained in the step (S3) is compressed to form a porous polymer layer 30, which is bonded between the electrode active material layer 20 and the first support layer 40 to be integrated with each other. (S4).

The porous polymer layer 30 may have a porous structure to well introduce the electrolyte solution into the electrode active material layer, and have a pore diameter of 0.01˜10 μm and a porosity of 5˜95%.

The porous coating may be formed in such a manner as to have a porous structure by phase separation or phase transition caused by a non-solvent during its preparation.

For example, polyvinylidene fluoride-co-hexafluoropropylene as a polymer is added to acetone used as a solvent to obtain a solution with 10% by weight of solids. To the obtained solution, water or ethanol as a non-solvent is added in an amount of 2 to 10% by weight to prepare a polymer solution.

This polymer solution undergoes a phase change during the drying procedure after coating, forming a phase-separated fraction of non-solvent and polymer. Wherein, the non-solvent portion becomes pores. Therefore, the size of the pores can be controlled according to the solubility of the non-solvent and the polymer and the amount of the non-solvent.

FIG. 7 is a photograph showing a cross section of a porous polymer layer 30 obtained by one embodiment of the present invention.

Meanwhile, if the porous polymer layer 30 is formed by coating a polymer solution (30') on one surface of the electrode active material layer 20, followed by drying, and then the first support layer 40 is formed by laminating thereon , the binder component in the polymer solution (30′) for bonding the electrode active material layer 20 and the first support layer 40 may solidify, making it difficult to maintain a strong adhesion between the two layers force.

Furthermore, unlike the preferred production method of the present invention using a first porous support layer prepared in advance, if the porous support layer is formed by coating a polymer solution on a porous polymer layer, then unlike the first porous support layer of the present invention, Compared with the porous support layer, such a porous support layer formed by coating a polymer solution has poorer mechanical properties, and thus cannot effectively prevent the detachment of the electrode active material layer.

In contrast, according to the preferred production method of the present invention, after the first support layer 40 is placed on top of the applied polymer solution (30'), the adhesive components are then cured, and then they are coated together using a coating doctor blade 60 In the case of , the porous polymer layer 30 bonded between the electrode active material layer 20 and the first support layer 40 so as to be integrated with each other is thus formed.

Meanwhile, the second support layer 50 may be formed by compressing on the other surface of the current collector before the step (S1) or after the step (S4). The second support layer 50 can suppress the short circuit of the current collector 10, thereby further improving the flexibility of the electrode.

The second support layer 50 may be a polymer film, and the polymer film may be made of any one selected from polyolefin, polyester, polyimide, polyamide and mixtures thereof.

In addition, the present invention provides a secondary battery comprising: a positive electrode, a negative electrode, a separator disposed between the positive electrode and the negative electrode, and an electrolyte, wherein at least one of the positive electrode and the negative electrode is One is formed by the above-mentioned electrode for a secondary battery.

The secondary battery of the present invention may be in a general form of stacking, winding or stacking/folding, and it may also be in a special form of a cable type.

In addition, the present invention provides a cable-type secondary battery including: an inner electrode; a separator surrounding an outer surface of the inner electrode to prevent a short circuit between the electrodes; and an outer electrode wound in a spiral shape. Thereby formed around the outer surface of the separator, wherein at least one of the inner electrode and the outer electrode is formed by the above-mentioned electrode for a secondary battery according to the present invention.

Here, the term "in a helical shape" is used to refer to a helical shape that rotates at a specific area while moving, including a general spring form.

The external electrodes may be in the form of strips extending uniaxially.

The external electrodes may be helically wound so as not to overlap in width thereof or to overlap in width thereof. For example, in order to prevent deterioration of battery performance, the sheet-form external electrodes may be spirally wound at intervals within twice the length of their width so as not to overlap.

Alternatively, the external electrodes may be helically wound while being overlapped in width thereof. In this case, in order to suppress an excessive increase in the internal resistance of the battery, the external electrode may be spirally wound such that the width of its overlapping portion may be within 0.9 times the width of the external electrode itself.

The internal electrode may be a hollow structure with a hollow center.

The inner electrode may have a core of an inner current collector disposed therein.

The core of the inner current collector can be made of: carbon nanotubes, stainless steel, aluminum, nickel, titanium, sintered carbon or copper; stainless steel treated with carbon, nickel, titanium or silver on its surface; aluminum-cadmium alloy ; Non-conductive polymers treated on their surface with a conductive material; Conductive polymers.

Alternatively, the internal electrode may be provided therein with a core for supplying lithium ions, which contains an electrolyte.

The core for supplying lithium ions may include a gel polymer electrolyte and a support.

In addition, the core for supplying lithium ions may contain a liquid electrolyte and a porous carrier.

Alternatively, the inner electrode may be provided with a filled core therein.

The filled core may be made of some materials that improve many properties of the cable-type battery, such as polymer resin, rubber, and inorganic substances in addition to the materials of the core forming the inner current collector and the core for supplying lithium ions. made, and can also be in a variety of forms including strands, fibers, powders, meshes and foams.

Meanwhile, FIG. 8 schematically shows a cable type secondary battery in which an internal electrode in the form of a sheet is wound on an outer surface of a core 110 for supplying lithium ions according to an embodiment of the present invention. A sheet-form internal electrode may be applied to a cable-type secondary battery, as shown in FIG. 8, and a sheet-form external electrode may similarly be wound on the outer surface of the separator.

Such a cable-type secondary battery according to one embodiment of the present invention includes: a core for supplying lithium ions containing an electrolyte; an inner electrode surrounding an outer surface of the core for supplying lithium ions and containing a current collector and an electrode active material layer; a separation layer surrounding an outer surface of the inner electrode to prevent a short circuit between electrodes; and an outer electrode formed by being wound in a helical shape so as to surround an outer surface of the separation layer, and A current collector and an electrode active material layer are included, wherein at least one of the internal electrode and the external electrode is formed by the above-mentioned electrode for a secondary battery according to the present invention.

The cable-type secondary battery of the present invention has a horizontal cross-section of a predetermined shape, a linear structure extending in a longitudinal direction, and flexibility so that it can freely change shape. The term 'predetermined shape' used herein is not limited to any particular shape, and means any shape that does not impair the properties of the present invention.

Among cable-type secondary batteries that can be designed by the present invention, a cable-type secondary battery 100 in which the above-described electrode for a secondary battery is used as an internal electrode is shown in FIG. 9 .

Referring to FIG. 9 , the cable-type secondary battery 100 includes: a core 110 for supplying lithium ions, which contains an electrolyte; an inner electrode, which surrounds the outer surface of the core 110 for supplying lithium ions; an isolation layer 170, which surrounding the outer surface of the inner electrode to prevent a short circuit between electrodes; and an outer electrode formed by being wound in a helical shape so as to surround the outer surface of the separation layer 170 and including an outer current collector 190 and an outer electrode active A material layer 180, wherein the internal electrode comprises an internal current collector 120, an internal electrode active material layer 130 formed on one surface of the internal current collector 120, an internal electrode active material layer 130 formed on the top surface of the internal electrode active material layer 130 The porous polymer layer 140 , the first porous support layer 150 formed on the top surface of the porous polymer layer 140 , and the second support layer 160 formed on the other surface of the inner current collector 120 .

As already mentioned above, the electrode for a secondary battery in the form of a sheet according to the present invention may also be used as an external electrode instead of an internal electrode, or may be used as both.

The core 110 for supplying lithium ions contains an electrolyte, the type of which is not particularly limited and may be selected from the group consisting of ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), ethylene carbonate, Vinyl ester (VC), diethyl carbonate (DEC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), methyl formate (MF), γ-butyrolactone (γ-BL), sulfolane, Non-aqueous electrolytes using methyl acetate (MA) or methyl propionate (MP); gel polymer electrolytes using PEO, PVdF, PVdF-HFP, PMMA, PAN, or PVAc; and using PEO, polypropylene oxide ( Solid electrolytes of PPO), polyethyleneimine (PEI), polyethylene sulfide (PES) or polyvinyl acetate (PVAc). In addition, the electrolyte may further comprise a lithium salt, and the lithium salt may be selected from: 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, lower aliphatic lithium carbonate, lithium tetraphenylborate and mixtures thereof. The core 110 for supplying lithium ions may consist of only electrolyte, and in particular, a liquid electrolyte may be formed by using a porous carrier.

In the present invention, the internal electrode may be a negative electrode or a positive electrode, and the external electrode may be a positive electrode or a negative electrode corresponding to the internal electrode.

Electrode active materials that can be used in the negative electrode and the positive electrode are the same as above.

Meanwhile, the isolation layer may be an electrolyte layer or a separator.

The electrolyte layer that acts as an ion channel can be made of gel-type polymer electrolytes using PEO, PVdF, PVdF-HFP, PMMA, PAN, or PVAc; or using PEO, polypropylene oxide (PPO), polyethyleneimine (PEI), polyethyl sulfide (PES) or polyvinyl acetate (PVAc) solid electrolytes. It is preferable to use a polymer or ceramic glass as the matrix for the skeleton forming solid electrolyte. In the case of a typical polymer electrolyte, even when ion conductivity is satisfied, ions move very slowly in terms of reaction rate. Therefore, it is preferable to use a gel-type polymer electrolyte that facilitates movement of ions compared to a solid electrolyte. The gel-type polymer electrolyte has poor mechanical properties, so a support may be included to improve the poor mechanical properties, and the support may be a porous structure support or a cross-linked polymer. The electrolyte layer of the present invention is capable of serving as a separator, so an additional separator can be omitted.

In the present invention, the electrolyte layer may further contain a lithium salt. Lithium salts improve ionic conductivity and response time. Non-limiting examples of lithium salts may 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, lithium chloroborane, lower aliphatic lithium carbonate, and lithium tetraphenylborate.

Examples of separators may include, but are not limited to: polymerized from polyolefins selected from ethylene homopolymers, propylene homopolymers, ethylene-butene copolymers, ethylene-hexene copolymers, and ethylene-methacrylate copolymers. porous polymer substrates made of polyester; polyacetal, polyamide, polycarbonate, polyimide, polyether ether ketone, polyether sulfone, polyphenylene ether, polyphenylene sulfide and A porous polymer substrate made of a polymer in polyethylene naphthalate; a porous substrate made of a mixture of inorganic particles and a binder polymer; or a separator having formed in said porous A porous coating on at least one surface of a polymeric substrate and comprising inorganic particles and a binder polymer.

In the porous coating formed of inorganic particles and a binder polymer, the inorganic particles are bound to each other by the binder polymer (i.e., the binder polymer connects and fixes the inorganic particles), and The porous coating remains bonded to the first support layer via the binder polymer. In the porous coating, the inorganic particles are filled in contact with each other, thereby forming interstitial volumes between the inorganic particles. The interstitial volumes between the inorganic particles become empty spaces to form pores.

Among them, in order to transfer the lithium ions of the core for supplying lithium ions to the external electrodes, it is preferable to use a non-woven fabric separator corresponding to a porous polymer substrate made of a polymer selected from polyester, polycondensation Aldehyde, polyamide, polycarbonate, polyimide, polyetheretherketone, polyethersulfone, polyphenylene oxide, polyphenylene sulfide, and polyethylene naphthalate.

In addition, the cable type secondary battery of the present invention has a protective coating 195 . The protective coating 195 acts as an insulator and is formed to surround the outer current collector, thereby protecting the electrode from moisture in the air and external impact. The protective coating can be made from conventional polymeric resins with a moisture barrier. The moisture blocking layer can be made of aluminum or liquid crystal polymer with good water blocking ability, and the polymer resin can be PET, PVC, HDPE or epoxy resin.

In addition, the present invention provides a cable-type secondary battery having more than two internal electrodes, including:

Two or more internal electrodes arranged parallel to each other;

an isolation layer surrounding the outer surfaces of the inner electrodes to prevent short circuits between the electrodes; and

An external electrode formed by being spirally wound so as to surround the outer surface of the separator, wherein at least one of the internal electrode and the external electrode is formed using the above-mentioned electrode for a secondary battery according to the present invention Forming.

In addition, the present invention provides a cable-type secondary battery having two or more internal electrodes comprising: two or more cores for supplying lithium ions containing an electrolyte; two or more internal electrodes arranged in parallel to each other, Each inner electrode surrounds the outer surface of each core for supplying lithium ions and includes a current collector and an electrode active material layer; a separation layer surrounds the outer surface of the inner electrode to prevent short circuit between the electrodes; and an outer electrode, which It is formed by winding in a helical shape so as to surround the outer surface of the separator, and contains a current collector and an electrode active material layer, wherein at least one of the inner electrode and the outer electrode is formed using the above-mentioned electrode according to the present invention. Formed with electrodes for secondary batteries.

Among cable-type secondary batteries having two or more internal electrodes that can be designed by the present invention, a cable-type secondary battery 200 in which the above-described secondary battery electrodes are used as internal electrodes is shown in FIG. 10 .

10, the cable-type secondary battery 200 includes: two or more cores 210 for supplying lithium ions, which contain an electrolyte; the outer surface of the core of the ions; the isolation layer 270, which surrounds the outer surface of the inner electrode to prevent a short circuit between the electrodes; formed, and include an outer current collector 290 and an outer electrode active material layer 280, wherein each inner electrode includes an inner current collector 220, an inner electrode active material layer 230 formed on one surface of the inner current collector 220, an inner electrode active material layer 230 formed on the The porous polymer layer 240 on the top surface of the internal electrode active material layer 230, the first porous support layer 250 formed on the top surface of the porous polymer layer 240, and another layer formed on the internal current collector 220 A second support layer 260 on one surface.

As already mentioned above, the electrode for a secondary battery in the form of a sheet according to the present invention may also be used as an external electrode instead of an internal electrode, or may be used as both.

In the cable type secondary battery 200 having a plurality of inner electrodes, the number of inner electrodes can be adjusted to control the loading amount of the electrode active material layer and battery capacity, and the possibility of short circuit can be prevented due to the existence of the plurality of electrodes.

Industrial applicability

The present invention has been described in detail. It should be understood, however, that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are given by way of illustration only, since various changes and modifications which are within the spirit and scope of the invention will be made from the detailed description, and It will become apparent to those skilled in the art.

Claims (65)

1. An electrode for a secondary battery in the form of a sheet, comprising: collector; an electrode active material layer formed on one surface of the current collector; a porous polymer layer formed on the electrode active material layer; and A first porous support layer formed on the porous polymer layer. 2. The electrode for a secondary battery according to claim 1, wherein said current collector is made of: stainless steel, aluminum, nickel, titanium, sintered carbon or copper; treated with carbon, nickel, titanium or silver on its surface stainless steel; aluminum-cadmium alloys; non-conductive polymers treated on their surface with a conductive material; conductive polymers; containing Ni, Al, Au, Ag, Pd/Ag, Cr, Ta, Cu, Ba or ITO Metal pastes of metal powders; or carbon pastes of carbon powders containing graphite, carbon black, or carbon nanotubes. 3. The electrode for a secondary battery according to claim 1, wherein the current collector is in the form of a mesh. 4. The electrode for a secondary battery according to claim 1, wherein the current collector further comprises an undercoat layer composed of a conductive material and a binder. 5. The electrode for a secondary battery according to claim 4, wherein the conductive material comprises any one selected from the group consisting of carbon black, acetylene black, Ketjen black, carbon fiber, carbon nanotube, graphene, and mixtures thereof. 6. The electrode for secondary batteries according to claim 4, wherein the binder is selected from the group consisting of polyvinylidene fluoride (PVDF), polyvinylidene fluoride-co-hexafluoropropylene, polyvinylidene fluoride-co- Trichloroethylene, polybutyl acrylate, polymethyl methacrylate, polyacrylonitrile, polyvinylpyrrolidone, polyvinyl acetate, polyethylene-co-vinyl acetate, polyethylene oxide, polyarylate, acetic acid Cellulose, cellulose acetate butyrate, cellulose acetate propionate, cyanoethyl pullulan, cyanoethyl polyvinyl alcohol, cyanoethyl cellulose, cyanoethyl sucrose, pullulan, carboxymethyl cellulose, Styrene-butadiene rubber, acrylonitrile-styrene-butadiene copolymer, polyimide and mixtures thereof. 7. The electrode for a secondary battery according to claim 1, wherein the current collector has a plurality of recesses on at least one surface thereof. 8. The electrode for a secondary battery according to claim 7, wherein the plurality of recesses are continuously patterned or intermittently patterned. 9. The electrode for a secondary battery according to claim 8, wherein the continuously patterned recesses are formed spaced apart from each other in the longitudinal direction. 10. The electrode for a secondary battery according to claim 8, wherein the intermittently patterned concave portion is formed by a plurality of holes. 11. The electrode for a secondary battery according to claim 10, wherein the plurality of holes are circular or polygonal. 12. The electrode for a secondary battery according to claim 1, wherein the first supporting layer is a porous film or non-woven fabric in the form of a mesh. 13. The electrode for a secondary battery according to claim 1, wherein said first support layer is made of any one selected from the group consisting of high-density polyethylene, low-density polyethylene, linear low-density polyethylene, ultra-high molecular weight polyethylene Polyethylene, polypropylene, polyethylene terephthalate, polybutylene terephthalate, polyester, polyacetal, polyamide, polycarbonate, polyimide, polyether ether ketone, Polyethersulfone, polyphenylene ether, polyphenylene sulfide, polyethylene naphthalate and mixtures thereof. 14. The electrode for a secondary battery according to claim 1, further comprising a conductive material coating layer having a conductive material and a binder on the first supporting layer. 15. The electrode for a secondary battery according to claim 14, wherein in the conductive material coating layer, the conductive material and the binder are present in a weight ratio of 80:20 to 99:1. 16. The electrode for a secondary battery according to claim 14, wherein the conductive material comprises any one selected from the group consisting of carbon black, acetylene black, Ketjen black, carbon fiber, carbon nanotube, graphene, and mixtures thereof. 17. The electrode for secondary batteries according to claim 14, wherein the binder is selected from the group consisting of polyvinylidene fluoride (PVDF), polyvinylidene fluoride-co-hexafluoropropylene, polyvinylidene fluoride-co- Trichloroethylene, polybutyl acrylate, polymethyl methacrylate, polyacrylonitrile, polyvinylpyrrolidone, polyvinyl acetate, polyethylene-co-vinyl acetate, polyethylene oxide, polyarylate, acetic acid Cellulose, cellulose acetate butyrate, cellulose acetate propionate, cyanoethyl pullulan, cyanoethyl polyvinyl alcohol, cyanoethyl cellulose, cyanoethyl sucrose, pullulan, carboxymethyl cellulose, Styrene-butadiene rubber, acrylonitrile-styrene-butadiene copolymer, polyimide and mixtures thereof. 18. The electrode for a secondary battery according to claim 1, wherein the porous polymer layer has a pore diameter of 0.01 to 10 [mu]m and a porosity of 5 to 95%. 19. The electrode for a secondary battery according to claim 1, wherein the porous polymer layer comprises a linear polymer having polarity, an oxide-based linear polymer, or a mixture thereof. 20. The electrode for secondary batteries according to claim 19, wherein said linear polymer with polarity is selected from the group consisting of: polyacrylonitrile, polyvinyl chloride, polyvinylidene fluoride (PVDF), polyvinylidene fluoride-co- - Hexafluoropropylene, polyvinylidene fluoride-co-trichloroethylene, polyethyleneimine, polymethylmethacrylate, polybutylacrylate, polyvinylpyrrolidone, polyvinyl acetate, polyethylene-co-acetic acid Vinyl esters, polyarylates, poly-p-phenylene terephthalamide and mixtures thereof. 21. The electrode for a secondary battery according to claim 19, wherein the oxide-based linear polymer is selected from the group consisting of polyethylene oxide, polypropylene oxide, polyoxymethylene, polydimethylsiloxane, and mixtures thereof. 22. The electrode for a secondary battery according to claim 1, further comprising a porous coating layer formed on the first support layer from a mixture of inorganic particles and a binder polymer. 23. The electrode for a secondary battery according to claim 1, further comprising a second support layer formed on the other surface of the current collector. 24. The electrode for a secondary battery according to claim 23, wherein the second support layer is a polymer film. 25. The electrode for a secondary battery according to claim 24, wherein said polymer film is made of any one selected from polyolefin, polyester, polyimide, polyamide, and mixtures thereof. 26. The electrode for a secondary battery according to claim 1, wherein when the electrode for a secondary battery is used as a negative electrode, the electrode active material layer comprises an active material selected from the group consisting of natural graphite, artificial graphite, or carbonaceous Materials; lithium-titanium composite oxide (LTO), and metals (Me) including Si, Sn, Li, Zn, Mg, Cd, Ce, Ni, and Fe; alloys of the metals; oxides of the metals ( MeOx); complexes of said metals and carbon; and mixtures thereof, and When the electrode for a secondary battery is used as a positive electrode, the electrode active material layer contains an active material selected from LiCoO ₂ , LiNiO ₂ , LiMn ₂ O ₄ , LiCoPO ₄ , LiFePO ₄ , LiNiMnCoO ₂ , LiNi _{1 -xyz} Co _x M1 _y M2 _z O ₂ (wherein M1 and M2 are each independently selected from: Al, Ni, Co, Fe, Mn, V, Cr, Ti, W, Ta, Mg and Mo, and x, y and z are each independently an atomic fraction of an oxide-forming element, wherein 0≤x<0.5, 0≤y<0.5, 0≤z<0.5, and x+y+z≤1) and mixtures thereof. 27. A method of preparing an electrode for a secondary battery in the form of a sheet, comprising: (S1) coating a slurry containing an electrode active material on one surface of a current collector, followed by drying, thereby forming an electrode active material layer; (S2) coating a polymer-containing polymer solution on the electrode active material layer; (S3) forming a first porous support layer on the polymer solution; and (S4) compressing the preparation obtained in step (S3) to form a porous polymer layer bonded between the electrode active material layer and the first porous support layer and integrated with each other. 28. The method for producing an electrode for a secondary battery in the form of a sheet according to claim 27, wherein the polymer solution contains a binder component. 29. The method for producing a sheet-form electrode for a secondary battery according to claim 28, wherein in the step (S3), the first porous support layer is formed on the polymer solution before the binder component is cured. 30. The method for preparing an electrode for a secondary battery in the form of a sheet according to claim 28, wherein in the step (S4), the preparation obtained in the step (S3) is compressed by a coating doctor blade to form a porous polymer layer, and the porous polymer layer is bonded between the electrode active material layer and the first porous support layer to be integrated with each other. 31. The method for preparing an electrode for a secondary battery in the form of a sheet according to claim 27, further comprising forming a second Two support layers. 32. A secondary battery comprising: a positive electrode, a negative electrode, a diaphragm arranged between the positive electrode and the negative electrode, and a non-aqueous electrolytic solution, Wherein at least one of the positive electrode and the negative electrode is the electrode for a secondary battery according to any one of claims 1 to 26. 33. The secondary battery according to claim 32, wherein the secondary battery is in a stacked, wound, stacked/folded or cable type form. 34. A cable-type secondary battery comprising: inner electrode; an isolation layer surrounding the outer surfaces of the inner electrodes to prevent short circuits between the electrodes; and an external electrode which surrounds the outer surface of the separation layer and is formed by being wound in a helical shape, wherein at least one of the internal electrode and the external electrode is formed by using the electrode for a secondary battery according to any one of claims 1 to 26. 35. The cable-type secondary battery according to claim 34, wherein the external electrode is in the form of a uniaxially extended strip. 36. The cable-type secondary battery according to claim 34, wherein the external electrodes are wound in a spiral shape so as not to overlap in a width thereof. 37. The cable-type secondary battery according to claim 36, wherein the external electrodes are spirally wound at intervals within a length twice the width thereof so as not to overlap. 38. The cable-type secondary battery according to claim 34, wherein the external electrodes are wound in a helical shape so as to overlap in a width thereof. 39. The cable-type secondary battery according to claim 38, wherein the external electrode is wound in a spiral shape such that a width of an overlapping portion thereof is within 0.9 times a width of the external electrode itself. 40. The cable-type secondary battery according to claim 34, wherein the inner electrode is a hollow structure in which a central portion is hollow. 41. The cable-type secondary battery according to claim 40, wherein the internal electrode comprises one or more electrodes for a secondary battery wound in a spiral shape. 42. The cable-type secondary battery according to claim 40, wherein the internal electrode is provided therein with a core of an internal current collector, a core for supplying lithium ions containing an electrolyte; or a filled core. 43. The cable-type secondary battery according to claim 42, wherein the core of the inner current collector is made of: carbon nanotubes, stainless steel, aluminum, nickel, titanium, sintered carbon or copper; , nickel, titanium or silver-treated stainless steel; aluminum-cadmium alloys; non-conductive polymers treated on their surface with a conductive material; conductive polymers. 44. The cable-type secondary battery according to claim 42, wherein the core for supplying lithium ions comprises a gel polymer electrolyte and a support. 45. The cable-type secondary battery according to claim 42, wherein the core for supplying lithium ions contains a liquid electrolyte and a porous carrier. 46. The cable-type secondary battery according to claim 42, wherein the electrolyte is selected from the group consisting of using 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), γ-butyrolactone (γ-BL), sulfolane, methyl acetate (MA) or methyl propionate (MP) non-aqueous electrolytes; gel polymer electrolytes using PEO, PVdF, PVdF-HFP, PMMA, PAN or PVAc; and using PEO, polypropylene oxide (PPO), Solid electrolytes of polyethyleneimine (PEI), polyethylene sulfide (PES), or polyvinyl acetate (PVAc). 47. The cable-type secondary battery according to claim 42, wherein the electrolyte further contains a lithium salt. 48. The cable-type secondary battery according to claim ₄₇ , wherein the lithium salt is selected from the group consisting _of : LiCl, LiBr, LiI, _LiClO4 , _LiBF4 , _LiB10Cl10 , _LiPF6 , _LiCF3SO3 , _{LiCF3CO 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, lower aliphatic lithium carbonate, lithium tetraphenyl borate and mixture. 49. The cable-type secondary battery according to claim 42, wherein the filled core is made of polymer resin, rubber and inorganic substances in the form of wire, fiber, powder, mesh and foam. 50. The cable-type secondary battery according to claim 34, wherein the internal electrode is a negative electrode or a positive electrode, and the external electrode is a positive electrode or a negative electrode corresponding to the internal electrode. 51. The cable-type secondary battery according to claim 34, wherein the separation layer is an electrolyte layer or a separator. 52. The cable-type secondary battery according to claim 51, wherein the electrolyte layer comprises an electrolyte selected from the group consisting of: a gel polymer electrolyte using PEO, PVdF, PMMA, PVdF-HFP, PAN, or PVAc; and using PEO , Polypropylene oxide (PPO), polyethyleneimine (PEI), polyethylene sulfide (PES) or polyvinyl acetate (PVAc) solid electrolyte. 53. The cable-type secondary battery according to claim 51, wherein the electrolyte layer further contains a lithium salt. 54. The cable-type secondary battery according to claim ₅₃ , wherein the lithium salt is selected from the group consisting _of : LiCl, LiBr, LiI, _LiClO4 , _LiBF4 , _LiB10Cl10 , _LiPF6 , _LiCF3SO3 , _{LiCF3CO 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, lower aliphatic lithium carbonate, lithium tetraphenyl borate and mixture. 55. The cable-type secondary battery according to claim 51, wherein said separator is made of a material selected from the group consisting of ethylene homopolymer, propylene homopolymer, ethylene-butene copolymer, ethylene-hexene copolymer, and ethylene-methanol. Porous polymer substrates made of polyolefin polymers in acrylate-based copolymers; composed of polyesters, polyacetals, polyamides, polycarbonates, polyimides, polyether ether ketones, polyether Porous polymer substrates made of polymers in sulfone, polyphenylene ether, polyphenylene sulfide, and polyethylene naphthalate; porous substrates made of mixtures of inorganic particles and binder polymers; Or a separator having a porous coating formed on at least one surface of the porous polymer substrate, and comprising inorganic particles and a binder polymer. 56. The cable-type secondary battery according to claim 55, wherein the porous polymer substrate is a porous polymer film substrate or a porous non-woven fabric substrate. 57. The cable-type secondary battery according to claim 34, further comprising a protective coating surrounding an outer surface of the outer electrode. 58. The cable-type secondary battery according to claim 57, wherein the protective coating is made of polymer resin. 59. The cable-type secondary battery according to claim 58, wherein the polymer resin comprises any one selected from the group consisting of PET, PVC, HDPE, epoxy resin, and mixtures thereof. 60. The cable-type secondary battery according to claim 58, wherein the protective coating further comprises a moisture barrier layer. 61. The cable type secondary battery according to claim 60, wherein the moisture blocking layer is made of aluminum or liquid crystal polymer. 62. A cable-type secondary battery, comprising: A core for supplying lithium ions, which contains an electrolyte; an inner electrode surrounding an outer surface of the core for supplying lithium ions, and comprising a current collector and an electrode active material layer; an isolation layer surrounding the outer surface of the inner electrode to prevent short circuits between the electrodes; and an outer electrode formed by being wound in a helical shape so as to surround the outer surface of the separator, and comprising a current collector and an electrode active material layer, wherein at least one of the internal electrode and the external electrode is formed using the electrode for a secondary battery according to any one of claims 1 to 26. 63. A cable-type secondary battery, comprising: Two or more internal electrodes arranged parallel to each other; an isolation layer surrounding the outer surfaces of the inner electrodes to prevent short circuits between the electrodes; and an external electrode which surrounds the outer surface of the separation layer and is formed by being wound in a helical shape, wherein at least one of the internal electrode and the external electrode is formed using the electrode for a secondary battery according to any one of claims 1 to 26. 64. A cable-type secondary battery, comprising: two or more cores for the supply of lithium ions, which contain the electrolyte; two or more internal electrodes arranged in parallel to each other, each internal electrode surrounding the outer surface of each core for supplying lithium ions and comprising a current collector and a layer of electrode active material; an isolation layer surrounding the outer surfaces of the inner electrodes to prevent short circuits between the electrodes; and an outer electrode formed by helically winding so as to surround the outer surface of the separator, and comprising a current collector and an electrode active material layer, wherein At least one of the internal electrode and the external electrode is formed using the electrode for a secondary battery according to any one of claims 1 to 26. 65. The cable-type secondary battery according to claim 64, wherein the internal electrode comprises one or more electrodes for a secondary battery wound in a spiral shape.