KR20160091732A - Method for Preparing Positive Electrode Having Insulation Coating portion and Positive Electrode Prepared Thereby - Google Patents

Abstract

The present invention provides a method for preparing an anode where an anode material containing an anode active material is covered on one surface or both surfaces of a current collector, comprising the steps of: (a) covering the anode material containing the anode active material on one surface or both surfaces of the current collector; (b) preparing an insulation coating agent containing an ultraviolet (UV) ray curable material; (c) covering the insulation coating agent on a boundary portion between an anode material coated part and an anode uncoated part; and (d) irradiating the insulation agent with UV rays to cure the insulation agent for forming an insulation coating part. The present invention enhances efficient in manufacturing the anode and enhances safety of the anode manufactured therefrom and a secondary battery.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a positive electrode including an insulated coating portion and a positive electrode using the same,

The present invention relates to a method of manufacturing an anode including an insulating coating portion and a cathode manufactured using the same. More specifically, the present invention relates to a method of applying an insulating coating agent containing an ultraviolet (UV) curing substance to a boundary portion between a cathode mixture applying portion and an anode non- The present invention relates to a method of manufacturing a positive electrode having improved efficiency of a manufacturing process and a positive electrode manufactured using the same and having improved safety.

As technology development and demand for various devices have increased, the demand for secondary batteries as energy sources is rapidly increasing. Among such secondary batteries, lithium secondary batteries having high energy density and voltage, long cycle life and low self- It has been commercialized and widely used.

Particularly, in the case of a lithium secondary battery, the demand for an energy source is rapidly increasing due to an increase in technology development and demand for a mobile device. Recently, the use of a lithium secondary battery as a power source for an electric vehicle (EV) and a hybrid electric vehicle , And the area of use is also expanding for applications such as power assisted power supply through gridization.

Generally, a lithium secondary battery has a structure in which a nonaqueous electrolyte solution is impregnated into an electrode assembly composed of a positive electrode containing a lithium transition metal oxide and a negative electrode including a carbonaceous active material and a porous separator. The positive electrode is prepared by coating a positive electrode mixture containing a lithium transition metal oxide on an aluminum foil, and the negative electrode is prepared by coating a copper foil with a negative electrode mixture containing a carbonaceous active material.

However, such a lithium secondary battery is liable to be short-circuited due to contact between the positive electrode and the negative electrode when exposed at a high temperature, and is liable to be short-circuited due to overcharge, external short circuit, nail penetration, local crush, Even when current flows, there is a risk of ignition / explosion as the battery is heated by heat generation.

Particularly, the separation membrane is a microporous membrane made of a polyolefin resin and has a heat-resistant temperature of only about 120 to 160 degrees, so that the separator can shrink due to heat generation inside the battery, thereby causing a larger reaction heat, There is a problem to be reached.

This phenomenon occurs mainly at the electrode active material coating end of the electrode current collector coated with the electrode active material during lamination, and various methods for lowering the possibility of shorting the electrode under external shock or high temperature have been attempted.

For example, in order to prevent the electrode tab from coming into contact with the upper end of the electrode assembly due to the movement of the electrode assembly in the state where the battery is completed, There is a method of attaching.

The insulating tape is wound around the collector tape to a length slightly extended from the top of the collector to the bottom of the collector, and is usually wound about 2 to 3 times in order to prevent loosening. However, such winding work of the insulating tape is very troublesome, It has a problem that it is easy to be released when bending.

Therefore, there is a high need for a manufacturing method of a positive electrode and a positive electrode using the same, which can secure safety while solving these problems fundamentally.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems of the prior art and the technical problems required from the past.

The present invention provides a method of manufacturing a positive electrode including an application of an insulating coating containing an ultraviolet (UV) curable material on a boundary portion between a cathode mixture applying portion and a cathode uncoated portion.

It is another object of the present invention to provide a secondary battery having improved safety even in an abnormal state using a positive electrode manufactured by the above-described method.

Accordingly, the present invention is a method for producing a positive electrode coated with a positive electrode mixture containing a positive electrode active material on one surface or both surfaces of a current collector,

(a) applying a positive electrode mixture containing a positive electrode active material to one surface or both surfaces of a current collector;

(b) preparing an insulating coating agent comprising an ultraviolet (UV) curable material;

(c) applying an insulating coating agent to a boundary portion between the cathode mixture applying portion and the anode uncoated portion; And

(d) curing the insulating coating agent by irradiating ultraviolet rays (UV) to form an insulated coating portion;

And a method for manufacturing the anode.

In general, when the separator end shrinks due to a reaction heat generated in an abnormal operation process of a battery, a short circuit may occur due to contact between the anode and the cathode.

Particularly, in the secondary battery, the application amount (coating area) of the negative electrode active material is relatively larger than that of the positive electrode active material due to the difference in operation efficiency between the positive electrode active material and the negative electrode active material. In this case, And the risk of ignition may be high.

Therefore, in the present invention, an insulation coated portion in which a UV curable material is cured is formed at a boundary portion between the cathode mixture applying portion and the anode uncoated portion, so that even if the separator end shrinks during abnormal operation of the battery, thereby preventing the generation of shorts and ensuring safety and efficiency of the manufacturing process.

In the present invention, the positive electrode uncoated portion may include a portion of the current collector where the positive electrode mixture is not applied, specifically, a portion where a positive electrode tab protruding outward from the current collector is formed.

The insulating coating agent may be applied in the form of covering the positive electrode material mixture applying portion and the positive electrode uncoated portion at the boundary portion between the positive electrode material mixture applying portion and the positive electrode uncoated portion. For example, at the boundary between the positive electrode material mixture applying portion and the positive electrode non- As shown in Fig.

The amount of the insulated coating portion applied on the positive electrode material mixture portion and the amount of the insulated coating portion applied on the positive electrode uncoated portion may be 3: 7 to 7: 3 based on the total weight of the insulated coating portion, 6: 4. ≪ / RTI >

When the amount of the insulated coating portion applied on the positive electrode material mixture applying portion and the area of the insulated coating portion applied on the positive electrode uncoated portion are out of the above range, the internal resistance of the battery increases or the effect of preventing the internal short- It is not desirable because it can not.

Further, the width of the insulated coating portion coated on the positive electrode mix portion with respect to the length direction of the current collector is preferably 0.05 to 20% of the total length of the current collector from the boundary of the positive electrode mixture portion and the positive electrode non- %, And more specifically, an insulating coating agent can be applied so as to be 3 to 15%.

When the width of the insulated coating portion coated on the positive electrode mix portion is less than 0.05% of the total length of the current collector, the area coated on the positive electrode mixture may be too small to cause a short circuit with the negative electrode collector. So that the resistance inside the battery may increase, which is not preferable.

The width of the insulated coating portion coated on the positive electrode uncoated portion with respect to the longitudinal direction of the current collector may be 0.05% to 20% of the total length of the current collector from the boundary between the positive electrode mixture portion and the positive electrode non- , And more specifically 3 to 15%.

If the width of the insulated coating portion coated on the anode uncoated portion is less than 0.05% of the total length of the current collector, a short circuit may occur due to contact with the negative electrode active material. If the width exceeds 20%, the resistance inside the battery may increase. It is not preferable because a problem may occur in the welding process.

Specifically, the width of the insulated coating portion coated on the positive electrode mix portion and the width of the insulated coating portion coated on the positive electrode uncoated portion, from the boundary between the positive electrode mixture portion and the positive electrode non-coated portion, mm to 15 mm, and more specifically from 3 mm to 12 mm.

An insulating coating agent may be applied so that the width of the insulated coating portion is equal to the width of the current collector based on the width direction of the current collector.

The thickness of the insulating coating portion formed at the boundary portion between the anode mixture coating portion and the anode uncoated portion may be 1 占 퐉 to 1000 占 퐉 based on the current collector, and more specifically, 10 占 퐉 to 700 占 퐉.

In addition, the thickness of the insulating coating formed on the cathode mixture portion may be 0.1 to 990 占 퐉 based on the positive electrode mixture, and specifically, the insulating coating agent may be coated to have a range of 0.5 to 900 占 퐉.

If the thickness of the insulation coating portion is out of the above range, the desired insulation effect may not be exhibited or resistance inside the battery may increase.

In the present invention, when an ultraviolet ray is irradiated with an insulating coating agent, an ultraviolet curable material exhibiting a high intermolecular binding force can be used as the crosslinking is performed by a chemical reaction.

Specifically, the ultraviolet curable material may be at least one selected from the group consisting of an acrylate oligomer having at least one acryl group, an acrylate monomer, and a vinyl ether monomer.

As one example, the acrylate oligomer may be at least one selected from the group consisting of urethane acrylate, polyester acrylate, epoxy acrylate, and silicone acrylate and may have a number average molecular weight of 50 to 5000.

The acrylate-based monomer may be monofunctional or multifunctional, for example, hydroxyethyl acrylate (HEA), hydroxyethyl methacrylate (HEMA), 1,6-hexanediol diacrylate (HDDA ), Tripropylene glycol diacrylate (TPGDA), trimethylolpropane triacrylate (TMPTA), pentaerythritol triacrylate (PETA), and dipentaerythritol hexaacrylate (DPHA) It can be more than one.

The vinyl ether monomer may be monofunctional or multifunctional and may be selected from the group consisting of, for example, butanediol monovinyl ether, 1,4-cyclohexanedimethanol monovinyl ether and triethylene glycol divinyl ether. It can be more than one.

In addition, the insulating coating agent may include a photoinitiator, a photoinitiator, and a thickener in addition to the ultraviolet curable material.

The photoinitiator may be selected from the group consisting of dialkoxyacetophenone, benzyl ketal, hydroxyalkyl phenyl ketone, benzoyl oxime ester, aminoketone, onium salt of triarylsulfonyl salt, 2,4,6-trimethylbenzoyl- Phosphine oxide and 2-hydroxy-2-methyl-1-phenyl-propan-1-one.

The thickening agent may be at least one selected from the group consisting of carboxymethylcellulose, hydroxyethylcellulose, polyvinyl alcohol, and polyvinyl acetate.

The content of the photoinitiator may range from 0.01% to 5%, and more specifically, from 0.1% to 3% based on the total weight of the insulating coating.

When the content of the photoinitiator is less than 0.01% based on the total weight of the insulating coating agent, the ultraviolet polymerization reaction slows down. When the content of the photoinitiator exceeds 5%, the ultraviolet polymerization reaction is accelerated. However, not.

When the photoinitiator and the thickener are included at the same time, the content of the thickener may be in the range of 0.01% to 5%, more specifically 0.1% to 3% based on the total weight of the insulating coating agent, The content of the thickener may range from 1% to 50%, and in particular from 5% to 30%, based on the total weight of the insulating coating.

When the content of the thickener is less than 5% based on the total weight of the insulating coating agent, the optimum effect due to the addition of the thickener can not be obtained. When the content of the thickener exceeds 50%, the ratio of the ultraviolet- So that it is not preferable.

In some cases, the ultraviolet ray-curable resin composition may be used in an organic solvent in an amount of 45% to 99% based on the total weight of the insulating coating agent. Examples of the organic solvent include n-hexane, Hydrocarbons such as octane, cyclohexane, and cyclopentane; Aromatic hydrocarbons such as toluene, xylene and ethylbenzene; Alcohols such as methanol, ethanol, n-butanol, ethylene glycol monomethyl ether and propylene glycol monomethyl ether; Esters such as ethyl acetate, n-butyl acetate, n-amyl acetate, ethylene glycol monomethyl ether acetate and propylene glycol monomethyl ether acetate; Ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl n-amyl ketone, and cyclohexanone; Polyalkylene glycol dialkyl ethers such as diethylene glycol dimethyl ether and diethylene glycol dibutyl ether; Ethers such as 1,2-dimethoxyethane, tetrahydrofuran and dioxane; N-methylpyrrolidone, dimethylformamide, dimethylacetamide or ethylene carbonate may be used alone or in combination of two or more thereof

In step (c), the insulating coating is selected from the group consisting of spray coating, roll coating, die coating, gravure printing, and bar coating The positive electrode mixture portion can be applied to the positive electrode uncoated portion using one or more of the following methods.

In the step (d), the insulating coating may be formed by irradiating ultraviolet rays having a wavelength range of about 100 to 380 nm with an ultraviolet lamp to an insulating coating agent within a time range of several seconds to several minutes to cure the insulating coating agent.

In general, curing a thermosetting material requires a heater having a large area ratio to form a high heat or drying condition, and it is also possible to use a separator which can adversely affect other components of the other cell due to exposure to heat for a long time. It may cause shrinkage.

Thus, the UV-curable material can efficiently form the insulating coating portion with a small energy amount in a relatively short time while using an ultraviolet light source having a small volume ratio, thereby minimizing electrode damage due to heating while improving the efficiency of the manufacturing process have.

The present invention provides a positive electrode manufactured by the above method.

The insulated coating portion of the positive electrode may be coated to cover the coating end portion of the positive electrode material mixture applying portion.

The insulated coating portion of the positive electrode may be coated at the boundary between the positive electrode mixture applying portion and the positive electrode uncoated portion so as to extend toward the positive electrode material mixture applying portion and the positive electrode uncoated portion.

The amount of the insulated coating portion coated on the positive electrode material mixture portion of the positive electrode and the amount of the insulated coating portion coated on the positive electrode uncoated portion may be 3: 7 to 7: 3 based on the total weight of the insulated coating portion, 6 to 6: 4.

When the amount of the insulated coating portion applied on the positive electrode material mixture applying portion and the area of the insulated coating portion applied on the positive electrode uncoated portion are out of the above range, the internal resistance of the battery increases or the effect of preventing the internal short- It is not desirable because it can not.

The width of the insulated coating portion coated on the positive electrode mix portion is from 0.05% to 20% relative to the total length of the current collector to the positive electrode mixture portion at the boundary between the positive electrode mixture portion and the positive electrode non- And in particular can be from 3 to 15%.

When the width of the insulated coating portion coated on the positive electrode mix portion is less than 0.05% of the total length of the current collector, the area applied on the positive electrode mixture is too small to cause a short circuit with the negative electrode collector. The area coated on the joint portion is excessively large, so that the resistance inside the battery may increase, which is not preferable.

The width of the insulated coating portion coated on the positive electrode uncoated portion with respect to the longitudinal direction of the current collector may be 0.05% to 20% of the total length of the current collector from the boundary between the positive electrode mixture portion and the positive electrode non- , And more specifically from 3 to 15%.

If the width of the insulated coating portion coated on the anode uncoated portion is less than 0.05% of the total length of the current collector, a short circuit may occur due to contact with the negative electrode active material. If the width exceeds 20%, the resistance inside the battery may increase. It is not preferable because a problem may occur in the welding process.

Specifically, the width of the insulated coating portion coated on the positive electrode mix portion and the width of the insulated coating portion coated on the positive electrode uncoated portion, from the boundary between the positive electrode mixture portion and the positive electrode non-coated portion, mm to 15 mm, and more specifically from 3 mm to 12 mm.

The width of the insulated coating portion may be the same as the width of the current collector with respect to the width direction of the current collector.

The thickness of the insulating coating portion formed at the boundary portion between the cathode mixture applying portion and the anode uncoated portion may be from 1 m to 1000 m, and more specifically from 10 m to 700 m, based on the current collector.

In addition, the thickness of the insulating coating formed on the portion of the positive electrode material mixture may be 0.1 to 990 mu m, and more specifically, 0.5 to 900 mu m, based on the positive electrode material mixture.

If the thickness of the insulation coating portion defined above is too small, it is difficult to exhibit a desired insulation effect, and if it is too thick, the thickness of the electrode assembly may increase or the resistance inside the battery may increase.

The present invention provides a secondary battery, wherein the electrode assembly including the positive electrode, the negative electrode, and the separator is embedded in the battery case with the electrode assembly impregnated with the lithium-containing electrolyte.

The positive electrode is prepared, for example, by coating a mixture of a positive electrode active material, a conductive material and a binder on a positive electrode current collector, and then drying the mixture. Optionally, a filler may be further added to the mixture.

The cathode active material may be a layered compound such as lithium cobalt oxide (LiCoO ₂ ), lithium nickel oxide (LiNiO ₂ ), or a compound substituted with one or more transition metals; Lithium manganese oxides such as Li _{1 + x} Mn _{2 -x} O ₄ (where x is 0 to 0.33), LiMnO ₃ , LiMn ₂ O ₃ , LiMnO ₂ and the like; Lithium copper oxide (Li ₂ CuO ₂ ); Vanadium oxides such as LiV ₃ O ₈ , LiFe ₃ O ₄ , V ₂ O ₅ and Cu ₂ V ₂ O ₇ ; A Ni-site type lithium nickel oxide expressed by the formula LiNi _1-x M _x O ₂ (where M = Co, Mn, Al, Cu, Fe, Mg, B or Ga and x = 0.01 to 0.3); Formula _{LiMn 2-x M x O 2} ( where, M = Co, Ni, Fe , Cr, and Zn, or Ta, x = 0.01 ~ 0.1 Im) or Li ₂ Mn ₃ MO ₈ (where, M = Fe, Co, Ni, Cu, or Zn); LiMn ₂ O _{4 in} which a part of Li in the formula is substituted with an alkaline earth metal ion; Disulfide compounds; Fe ₂ (MoO ₄ ) ₃ , and the like. However, the present invention is not limited to these.

The conductive material is usually added in an amount of 1 to 50% by weight based on the total weight of the mixture including the cathode active material. Such a conductive material is not particularly limited as long as it has electrical conductivity without causing chemical changes in the battery, for example, graphite such as natural graphite or artificial graphite; Carbon black such as carbon black, acetylene black, ketjen black, channel black, furnace black, lamp black, and summer black; Conductive fibers such as carbon fiber and metal fiber; Metal powders such as carbon fluoride, aluminum, and nickel powder; Conductive whiskey such as zinc oxide and potassium titanate; Conductive metal oxides such as titanium oxide; Conductive materials such as polyphenylene derivatives and the like can be used.

The binder is a component that assists in bonding of the active material and the conductive material and bonding to the current collector, and is usually added in an amount of 1 to 50 wt% based on the total weight of the mixture containing the cathode active material. Examples of such binders include polyvinylidene fluoride, polyvinyl alcohol, carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene , Polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene butylene rubber, fluorine rubber, various copolymers and the like.

The filler is optionally used as a component for suppressing the expansion of the anode, and is not particularly limited as long as it is a fibrous material without causing a chemical change in the battery. Examples of the filler include olefin polymers such as polyethylene and polypropylene; Fibrous materials such as glass fibers and carbon fibers are used.

The negative electrode is manufactured by applying and drying an anode active material on an anode current collector, and may further include the above-described components as needed.

Examples of the negative electrode active material include carbon such as non-graphitized carbon and graphite carbon; _{Li x Fe 2 O 3 (0≤x≤1} ), Li x WO 2 (0≤x≤1), Sn x Me 1-x Me 'y O z (Me: Mn, Fe, Pb, Ge; Me' : Metal complex oxides such as Al, B, P, Si, Group 1, Group 2, Group 3 elements of the periodic table, Halogen, 0 < x < Lithium metal; Lithium alloy; Silicon-based alloys; Tin alloy; _{SnO, SnO 2, PbO, PbO} 2, Pb 2 O 3, Pb 3 O 4, Sb 2 O 3, Sb 2 O 4, Sb 2 O 5, GeO, GeO 2, Bi 2 O 3, Bi 2 O 4, and Bi ₂ O ₅ ; Conductive polymers such as polyacetylene; Li-Co-Ni-based materials and the like can be used.

In the present invention, the amount of the negative electrode active material applied to the current collector of the negative electrode may be greater than the amount of the positive electrode active material applied to the current collector of the positive electrode.

Generally, in the case of an anode active material, an irreversible capacity of about 10 to 20% is generated at the time of initial charging / discharging including the initial charging, and only about 80 to 90% of the irreversible capacity can be used reversibly. As a cathode active material, There is a problem that waste of the electrode material is caused by the irreversible capacity of about 10 to 20%. Accordingly, in the manufacturing process of the electrode, the amount of the negative electrode active material applied to the negative electrode current collector of the negative electrode is made larger than the amount of the positive electrode active material applied to the current collector of the positive electrode.

However, when the separator shrinks under an abnormal operating condition of the battery, the negative electrode active material and the positive electrode collector may come into contact with each other easily to cause a short circuit. In the present invention, a predetermined insulation coating agent is applied to the boundary portion between the positive electrode mixture- It is possible to solve the short circuit problem due to contact between the negative electrode active material and the positive electrode collector while minimizing the waste of the positive electrode active material.

The separation membrane is interposed between the anode and the cathode, and an insulating thin film having high ion permeability and mechanical strength is used. The pore diameter of the separator is generally 0.01 to 10 mu m, and the thickness is generally 5 to 300 mu m. Such separation membranes include, for example, olefinic polymers such as polypropylene, which are chemically resistant and hydrophobic; A sheet or nonwoven fabric made of glass fiber, polyethylene or the like is used. When a solid electrolyte such as a polymer is used as an electrolyte, the solid electrolyte may also serve as a separation membrane.

The lithium salt-containing electrolytic solution is a non-aqueous electrolytic solution consisting of a polar organic electrolytic solution and a lithium salt. As the electrolytic solution, a non-aqueous liquid electrolytic solution, an organic solid electrolyte, an inorganic solid electrolyte and the like are used.

Examples of the nonaqueous liquid electrolytic solution include N-methyl-2-pyrrolidinone, propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, gamma -Butyrolactone, 1,2-dimethoxyethane, tetrahydroxyfuran, 2-methyltetrahydrofuran, dimethylsulfoxide, 1,3-dioxolane, formamide, dimethylformamide, dioxolane , Acetonitrile, nitromethane, methyl formate, methyl acetate, triester phosphate, trimethoxymethane, dioxolane derivatives, sulfolane, methylsulfolane, 1,3-dimethyl-2-imidazolidinone, propylene carbonate Nonionic organic solvents such as tetrahydrofuran derivatives, ethers, methyl pyrophosphate, ethyl propionate and the like can be used.

Examples of the organic solid electrolyte include a polymer electrolyte such as a polyethylene derivative, a polyethylene oxide derivative, a polypropylene oxide derivative, a phosphate ester polymer, an agitation lysine, a polyester sulfide, a polyvinyl alcohol, a polyvinylidene fluoride, Polymers containing ionic dissociation groups, and the like can be used.

Examples of the inorganic solid electrolyte include Li ₃ N, LiI, Li ₅ NI ₂ , Li ₃ N-LiI-LiOH, LiSiO ₄ , LiSiO ₄ -LiI-LiOH, Li ₂ SiS ₃ , Li ₄ SiO ₄ , Nitrides, halides and sulfates of Li such as Li ₄ SiO ₄ -LiI-LiOH and Li ₃ PO ₄ -Li ₂ S-SiS ₂ can be used.

The lithium salt is a material that is readily soluble in the non-aqueous electrolyte, for example, 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, chloroborane lithium, lower aliphatic carboxylic acid lithium, lithium tetraphenyl borate and imide have.

For the purpose of improving the charge-discharge characteristics and the flame retardancy, the non-aqueous liquid electrolyte may contain, for example, pyridine, triethylphosphite, triethanolamine, cyclic ether, ethylenediamine, glyme, N, N-substituted imidazolidine, ethylene glycol dialkyl ether, ammonium salt, pyrrole, 2-methoxyethanol, aluminum trichloride and the like are added It is possible. In some cases, a halogen-containing solvent such as carbon tetrachloride or ethylene trifluoride may be further added to impart nonflammability, or a carbon dioxide gas may be further added to improve high-temperature storage characteristics.

In the present invention, the electrode assembly may comprise one of the following structures:

(i) a jelly-roll structure in which a positive electrode sheet and a negative electrode sheet are wound with a separator interposed therebetween;

(ii) a laminated structure in which two or more positive electrode plates and two or more negative electrode plates are stacked with a separator interposed therebetween;

(iii) a stack / folding structure in which at least two positive electrode plates and at least one negative electrode plate are laminated and joined together with a separator interposed therebetween, the two or more unit cells being wound by a separator film.

That is, the type of the electrode assembly included in the battery cell according to the present invention is not limited, and an electrode assembly suitable for a device or device to be mounted can be applied.

Among the electrode assemblies, a stacked or stacked / folded type electrode assembly is manufactured by stacking or winding predetermined unit cells, and the unit cells may have a bicell structure in which electrodes on both outer sides have the same polarity The electrodes on both outer sides may have a full cell structure having polarities different from each other, or a structure in which a bixel and a pull cell are mixed and used.

The battery case may be made of a laminate sheet including a metal layer and a resin layer. A preferable example of such a laminate sheet is an aluminum laminate sheet.

The present invention provides a battery pack including the battery cell as a unit cell and a device including the battery pack as a power source.

Typical examples of such devices include smart phones, smart phone cases, wearable devices, smart pads, tablet PCs, netbooks, or notebook computers as well as mid- to large-sized devices such as electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, , But the present invention is not limited to these.

The structure of these devices and their fabrication methods are well known in the art, and a detailed description thereof will be omitted herein.

The present invention can provide a method of manufacturing a positive electrode including an application of an insulating coating material containing an ultraviolet (UV) curable material to a boundary portion between a cathode mixture applying portion and a cathode uncoated portion, thereby improving the efficiency of the manufacturing process.

In addition, the present invention provides a positive electrode having an insulating coating portion including a predetermined material at a boundary portion between a positive electrode material mixture applying portion and a positive electrode uncoated portion, thereby preventing the secondary battery from being deformed or shrinking Thereby preventing the short circuit between the positive electrode and the negative electrode.

1 schematically shows a plan view (a) and a side view (b) of a cathode for a stacked type electrode assembly according to one embodiment of the present invention;
Fig. 2 schematically shows a partially enlarged view of a side view (b) according to Fig. 1; Fig. And
3 schematically shows a plan view (a) and a side view (b) of a positive electrode for a jelly-roll type electrode assembly according to another embodiment of the present invention;

Hereinafter, the present invention will be described with reference to Examples. However, the following Examples are intended to illustrate the present invention and the scope of the present invention is not limited thereto.

1 and 2 schematically show a cathode for a stacked type electrode assembly according to one embodiment of the present invention. In FIGS. 1 and 2, for convenience of explanation, shapes before the anode, the separator, and the cathode are laminated are shown.

1 (a) and 1 (b), an anode 100 according to the present invention includes a cathode current collector 110 and a cathode tab 120 protruding outward from the cathode current collector 110 .

The insulating coating portion 130 is formed on the cathode current collector 110 at the boundary between the cathode mixture applying portion 111 to which the cathode mixture 140 is applied and the cathode uncoated portion 112 to which the cathode mixture 140 is not applied have.

The positive electrode tab 120 to which the positive electrode mixture 140 is not applied may also be regarded as a kind of positive electrode uncoated portion.

In this embodiment, the insulating coating portion 130 is formed on the entire anode uncoated portion 112. However, in another embodiment, the insulating coating portion may be formed on only a part of the anode uncoated portion of the anode current collector.

Referring to FIG. 2, the insulated coating portion 130 of the positive electrode is coated to cover the coating end portion of the positive electrode material mixture applying portion 140, and at the boundary between the positive electrode material mixture applying portion 140 and the positive electrode non- The positive electrode mixture coating portion 140, and the positive electrode uncoated portion 112, respectively.

The amount of the insulated coating portion coated on the positive electrode material mixture portion 140 and the amount of the insulated coating portion coated on the positive electrode uncoated portion 112 may be 3: 7 to 7: 3 based on the total weight of the insulated coating portion.

The width w ₁ of the insulated coating portion 130 coated on the positive electrode mix portion coating portion 140 is set such that the width w ₁ of the positive electrode mixture portion coating portion 140 at the boundary between the positive electrode mixture portion applying portion 140 and the positive electrode non- And the width w ₂ of the insulated coating portion 130 coated on the positive electrode uncoated portion 112 may be in the range of 0.05 to 20% The positive electrode uncoated portion 112 may be 0.05% to 20% of the total length of the current collector 110 at the boundary between the positive electrode uncoated portion 112 and the positive electrode uncoated portion 112.

The width w ₁ of the insulated coating portion 130 applied on the positive electrode mixture applying portion 140 and the width w ₁ of the insulated coating portion 130 coated on the positive electrode uncoated portion 112, (W ₂ ) of the positive electrode mixture coating portion 130 may be in the range of 1 mm to 15 mm from the boundary between the positive electrode mixture applying portion and the positive electrode uncoated portion.

The cathode reference to the insulation coating unit thickness (h) of the current collector in the 1 ㎛ to 1000 ㎛ one can, the insulating coating thickness based on the positive electrode mixture coated portion (140) (h ₁₎ is 0.1 ㎛ to 990 ㎛ days .

The insulating coating 130 may be coated with the insulating coating 130 so that the width of the insulating coating 130 is the same as the width of the current collector 110 with respect to the width direction of the current collector.

3 (a) and 3 (b) are schematic diagrams showing a part of the anode of the jelly-roll type electrode assembly according to another embodiment of the present invention. In FIG. 3, the shape before rounding is shown for convenience of explanation.

3, the anode 200 includes a cathode mixture application portion 211 to which a cathode mixture 240 is applied on a current collector (aluminum foil 210) for manufacturing a jelly-roll type electrode assembly, and a cathode mixture 240 An insulating coating 230 is formed at the boundary of the uncoated cathode non-coated portion 212 and the anode tab 220 is attached to the end of the anode uncoated portion 212 to protrude upward. The positive electrode tab 220 is made of a metal strip having a relatively thicker thickness than the current collector 210 and is strongly attached to the current collector 210 by spot welding or the like.

The insulating coating part 230 is formed by curing an insulating coating material containing an ultraviolet curable material by ultraviolet rays.

The width of the other insulated coating portion 230 and the like can be appropriately analyzed with reference to Figs. 1 and 2. Fig.

The insulation coated portion 230 prevents a short circuit due to contact between the positive electrode and the negative electrode, thereby improving the safety of the secondary battery.

Claims (23)

A method for producing a positive electrode coated with a positive electrode mixture containing a positive electrode active material on one surface or both surfaces of a current collector,
(a) applying a positive electrode mixture containing a positive electrode active material to one surface or both surfaces of a current collector;
(b) preparing an insulating coating agent comprising an ultraviolet (UV) curable material;
(c) applying an insulating coating agent to a boundary portion between the cathode mixture applying portion and the anode uncoated portion; And
(d) curing the insulating coating agent by irradiating ultraviolet rays (UV) to form an insulated coating portion;
And a cathode. The method according to claim 1, wherein in the step (c), the positive electrode uncoated portion is a portion of the current collector where the positive electrode mixture is not applied. 3. The method of manufacturing a positive electrode according to claim 2, wherein the positive electrode uncoated portion has a positive electrode tab protruding outwardly from the current collector. The method of claim 1, wherein the ultraviolet ray-curable material is at least one selected from the group consisting of an acrylate oligomer having at least one acryl group, an acrylate monomer, and a vinyl ether monomer. 5. The method of claim 4, wherein the acrylate oligomer is at least one selected from the group consisting of urethane acrylate, polyester acrylate, epoxy acrylate, and silicone acrylate; The acrylate monomer may be at least one selected from the group consisting of hydroxyethyl acrylate (HEA), hydroxyethyl methacrylate (HEMA), 1,6-hexanediol diacrylate (HDDA), tripropylene glycol diacrylate (TPGDA) At least one selected from the group consisting of propane triacrylate (TMPTA), pentaerythritol triacrylate (PETA) and dipentaerythritol hexaacrylate (DPHA); And the vinyl ether monomer is at least one selected from the group consisting of butanediol monovinyl ether, 1,4-cyclohexanedimethanol monovinyl ether, and triethylene glycol divinyl ether. The method according to claim 1, wherein the insulating coating agent comprises a photoinitiator, a photoinitiator, and a thickener. The method of claim 6, wherein the photoinitiator is selected from the group consisting of dialkoxyacetophenone, benzyl ketal, hydroxyalkyl phenyl ketone, benzoyl oxime ester, aminoketone, onium salts of triarylsulfonyl salts, Trimethylbenzoyl-diphenyl-phosphine oxide and 2-hydroxy-2-methyl-1-phenyl-propane-1-one. 7. The method according to claim 6, wherein the thickening agent is at least one selected from the group consisting of carboxymethylcellulose, hydroxyethylcellulose, polyvinyl alcohol, and polyvinyl acetate. 7. The method of claim 6, wherein the content of the photoinitiator ranges from 0.01% to 5% based on the total weight of the insulating coating agent, and the content of the thickener ranges from 1% to 50% Gt; < / RTI > The method according to claim 1, wherein the insulating coating is applied by spray coating, roll coating, die coating, gravure printing, or bar coating Wherein the positive electrode coating material is applied to the positive electrode uncoated portion by using at least one method selected from the group consisting of the following. A positive electrode, characterized in that it is produced by the process according to claim 1. 12. The anode according to claim 11, wherein the insulating coating portion of the anode is coated so as to cover an application end portion of the cathode mixture applying portion. 12. The anode according to claim 11, wherein the insulated coating portion of the anode is coated at a boundary between the cathode mixture application portion and the anode uncoated portion so as to extend toward the anode mixture coating portion and the anode uncoated portion. 14. The battery pack according to claim 13, wherein the amount of the insulated coating portion coated on the positive electrode material mixture portion of the positive electrode and the amount of the insulated coating portion coated on the positive electrode uncoated portion are 3: 7 to 7: 3 based on the total weight of the insulated coating portion The anode. 14. The method according to claim 13, wherein the width of the insulated coating portion coated on the positive electrode mix portion is from the boundary between the positive electrode mixture portion and the positive electrode uncoated portion to the positive electrode mixture portion, 0.05% to 20%. 14. The method according to claim 13, wherein the width of the insulated coating portion coated on the positive electrode uncoated portion is from the boundary between the positive electrode uncoated portion and the positive electrode uncoated portion to 0.05 < % To 20%. 14. The method according to claim 13, wherein the width of the insulated coating portion coated on the positive electrode mix portion and the width of the insulated coating portion coated on the positive electrode uncoated portion are set such that the width of the boundary between the positive electrode mixture portion and the positive electrode non- Is in the range of 1 mm to 15 mm. 14. The anode according to claim 13, wherein the width of the insulating coating portion is equal to the width of the current collector with respect to the width direction of the current collector. 14. The anode according to claim 13, wherein the thickness of the insulating coating on the anode is 1 占 퐉 to 1000 占 퐉 based on the current collector. The secondary battery according to claim 11, wherein the electrode assembly including the positive electrode, the negative electrode and the separator is embedded in the battery case with the lithium-containing electrolyte impregnated therein. The secondary battery according to claim 20, wherein the amount of the negative electrode active material applied to the current collector of the negative electrode is greater than the amount of the positive electrode active material applied to the current collector of the positive electrode. 21. The secondary battery of claim 20, wherein the electrode assembly is of a jelly-roll type, a stacked type, or a stack / folding type. A device comprising a secondary cell according to claim 20.

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