KR20170088614A - Electrolytic copper foil with high strength for current collector of lithium secondary battery and lithium secondary battery comprising the same - Google Patents

Abstract

The present invention relates to an electrolytic copper foil having high strength for a current collector of a lithium secondary battery, and to the current collector and the lithium secondary battery manufactured using the same, and specifically, to the high-strength electrolytic copper foil in which room-temperature half power bandwidth is maintained constant even after high-temperature heat treatment. The electrolytic copper foil according to the present invention can maintain high strength characteristics even after heat treatment and can prevent the occurrence of wrinkles and warping phenomena, thereby providing the electrolytic copper foil which can withstand the volume change and heat generation phenomenon of the lithium secondary battery and has stably maintained capacity and performance.

Description

TECHNICAL FIELD The present invention relates to an electrolytic copper foil for a lithium secondary battery having a high strength and a lithium secondary battery including the same,

The present invention relates to an electrolytic copper foil for a lithium secondary battery current collector having a high strength and a current collector and a lithium secondary battery manufactured using the same. More particularly, the present invention relates to a lithium secondary battery having a full width at half maximum (FWHM) To a high strength electrolytic copper foil.

Research is underway to focus on alternative energy sources and alternate power sources, ie, electrochemical energy production, in order to respond to soaring energy consumption and change to environmentally friendly consumption patterns. In particular, a secondary battery has been developed as a storage and conversion method of electrochemical energy. Lithium secondary batteries having excellent discharge performance and high energy density among secondary batteries are being used not only for small IT devices such as mobile phones and notebook PCs, Is expected to be applied.

In the lithium secondary battery, the negative electrode is composed of a collector coated with a negative active material layer, and a copper foil is generally used as a material for the negative electrode collector. The copper foil is mainly made of rolled copper foil by rolling. However, it is difficult to manufacture a copper foil having a high production cost and a wide width, and adhesion to the active material is lowered due to contamination caused by lubricant used in rolling. Is lowered. Accordingly, development of a technology using an electrolytic copper foil as a current collector replacing the rolled copper foil has attracted attention.

As the thickness of the electrolytic copper foil used as the anode current collector of the lithium secondary battery increases, the amount of the active material that can be included increases, thereby increasing the capacity of the secondary battery. However, if the thickness of the copper foil is thinner, The possibility of breakage increases. Therefore, in the case of the ultra thin, the characteristic of the tensile strength becomes more important. In addition, in the case of a metal-based or composite-based active material that has recently been spotlighted for high-capacity use, there is a demand for a high-strength electrolytic copper foil capable of coping with a large volume expansion (see Non-Patent Document 1).

Lithium secondary batteries are accompanied by heat generation due to volume change and overcharging during charging and discharging. In addition, the active material on the current collector has a problem that the adhesion of the active material coated on the surface of the current collector is weakened by the physical force such as deterioration, swelling or external impact of the lithium secondary battery and a gap is generated in the close contact surface between the current collector and the active material. Currents and electrons are concentrated at specific points (see Patent Document 1). Therefore, in order to cope with the high temperature drying conditions in the active material coating and the volume expansion and exothermic phenomena at the time of repeated charging and discharging of the battery, tensile strength is maintained at the time of heat treatment and adhesion with the active material is excellent and wrinkles, A copper foil that does not occur is necessary.

 Under these circumstances, the present inventors have made intensive researches to develop an electrolytic copper foil that maintains high strength characteristics even after heat treatment. As a result, it has been found that by producing an electrolytic copper foil having a constant room temperature half width and a room temperature tensile strength even after heat treatment, And the present invention has been completed.

Korean Patent Publication No. 10-2014-0078883

 Kim TR et al., Carbon letters, 2007, 8 (4), 335-339.

SUMMARY OF THE INVENTION An object of the present invention is to provide an electrolytic copper foil in which the room temperature half width is maintained constant even after heat treatment.

Another object of the present invention is to provide a current collector for a lithium secondary battery manufactured using the electrolytic copper foil.

It is still another object of the present invention to provide a lithium secondary battery comprising a current collector manufactured using the electrolytic copper foil.

In order to achieve the above object, a first aspect of the present invention is an electrolytic copper foil for a lithium secondary battery current collector, wherein an X-ray diffraction spectrum of the electrolytic copper foil shows a full width at half of a diffraction peak with respect to a (111) Maximum, FWHM) of 0.18 to 0.35 deg., And the half-width after heat treatment at 130 deg. C for 10 minutes is maintained at 97% or more of the room temperature half-value width.

In the present invention, the tensile strength at room temperature of the electrolytic copper foil is 45 to 70 kgf / mm ² , And the tensile strength after heat treatment at 130 占 폚 for 10 minutes is 90% or more of the tensile strength at room temperature.

A second aspect of the present invention provides a current collector for a lithium secondary battery manufactured using the electrolytic copper foil.

A third aspect of the present invention provides a lithium secondary battery comprising a current collector manufactured using the electrolytic copper foil.

The electrolytic copper foil according to the present invention can maintain the high strength characteristics even after the heat treatment and can prevent the occurrence of wrinkles and warping phenomenon and can endure the volume change and heat generation phenomenon of the lithium secondary battery and maintain the capacity and performance stably You can provide an electric boat.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is an X-ray diffraction spectrum and half-width of an electrolytic copper foil for a lithium secondary battery current collector according to Example 1 of the present invention at room temperature. Fig.
FIG. 2 is a graph showing an X-ray diffraction spectrum and a half-value width of an electrolytic copper foil for a current collector for a lithium secondary battery according to Example 1 of the present invention after heat treatment at 130 ° C. for 10 minutes.

Hereinafter, the present invention will be described in detail with reference to Examples. However, the present invention is not limited to or limited by Examples. In describing the embodiments, a detailed description of well-known functions or constructions may be omitted so as to clarify the gist of the present invention. Like reference numerals refer to like elements throughout the specification.

Throughout this specification, when an element is referred to as "including " an element, it is understood that the element may include other elements as well, without departing from the other elements unless specifically stated otherwise.

Throughout this specification, the term "combination thereof" included in the expression of the machine form means one or more combinations or combinations selected from the group consisting of the constituents described in the expression of the machine form, And the like.

Hereinafter, an electrolytic copper foil for a lithium secondary battery current collector having high strength according to the present invention, a current collector manufactured using the same, and a lithium secondary battery will be described in detail.

The electrolytic copper foil for a lithium secondary battery current collector according to the present invention has a full width at half maximum of valence at diffraction peaks with respect to the (111) crystal face in the X-ray diffraction spectrum with respect to the electrolytic copper foil of 0.18 to 0.35 degrees, And the width thereof is maintained at 97% or more of the room temperature half value width.

The physical properties of the electrolytic copper foil can exhibit properties meeting the requirements by controlling factors such as gloss, tensile strength, elongation, and crystal orientation, thereby making it possible to produce an electrolytic copper foil of desired quality. In the X-ray diffraction spectrum of the electrolytic copper foil at room temperature and the electrolytic copper foil after the high-temperature heat treatment, the half-width value of the peak to the (111) plane of the electrolytic copper foil was constant The electrolytic copper foil can exhibit excellent physical properties and high strength characteristics at room temperature and can produce the electrolytic copper foil that retains the characteristics even after high temperature treatment.

The half-value width means a difference in two different diffraction angles (2 &thetas;) corresponding to the intensity value corresponding to half of the maximum intensity value shown in the peak curve for the (111) crystal face of the electrolytic copper foil in the X-ray diffraction spectrum do. In the electrolytic copper foil manufacturing process according to an embodiment of the present invention, the half-width at room temperature measured on the (111) plane may be 0.18 to 0.35, and the range may be in the range of Width range. When the half width of the electrolytic copper foil is smaller than 0.18 °, it corresponds to a case where the copper crystal grains are large in the copper foil. In this case, it is difficult to realize the high strength of the electrolytic copper foil and wrinkles may occur in the copper foil. Further, when the half width of the electrolytic copper foil is larger than 0.35 deg., Copper crystal grains in the copper foil are small. In this case, it is difficult to control the mechanical properties such as elongation and gloss in addition to the strength. There is a problem in the handling of the process.

The tensile strength at room temperature of the electrolytic copper foil according to the present invention is 45 to 70 kgf / mm < ² > And the tensile strength after heat treatment at 130 占 폚 for 10 minutes may be 90% or more of the tensile strength at room temperature. When the tensile strength of the electrolytic copper foil is 45 kgf / mm ² , Wrinkles may occur due to low mechanical strength in a roll to roll operation in a lithium secondary battery manufacturing process, and the tensile strength is 70 kgf / mm < ^{2 >} , The elongation of the electrolytic copper foil may be lowered and breakage may occur in the battery manufacturing process.

When the tensile strength of the electrolytic copper foil after the heat treatment is 90% or more of the room temperature tensile strength, the strength can be maintained even after the heat treatment, high temperature drying conditions during the coating of the active material and softening during the roll press process do not occur, So that the yield can be increased.

The elongation of the electrolytic copper foil according to the present invention may be 2 to 20%. If the elongation percentage is less than 2%, breakage may occur due to volume change of the active material layer during charging and discharging, which may cause defects. When the elongation percentage is more than 20% Lt; / RTI >

The surface roughness Rz of each of the matte side (M side) and the shiny side (S side) of the electrolytic copper foil according to the present invention may be 2.0 m or less.

On one side of the electrolytic copper foil, a glossy shiny surface (S-plane) is formed with relatively low illuminance, and a mat surface (M-plane) having the same or higher relative illuminance is formed on the other surface. If the surface roughness Rz exceeds 2.0 m, the thickness of the active material layer may be uneven and charge and discharge may not be uniformly performed, and the lifetime characteristics of the lithium battery may be deteriorated.

The thickness of the electrolytic copper foil according to the present invention may be 5 to 20 탆. As the thickness of the electrolytic copper foil is thinner, the current collector with the active material can be contained in a large amount in the secondary battery, which is advantageous for high capacity. However, if the thickness is less than 5 탆, the mechanical strength may be lowered and the possibility of breakage may increase. If it exceeds 20 μm, the amount that can be contained in the secondary battery is reduced, which may make it difficult to increase the capacity.

The electrolytic copper foil according to one embodiment of the present invention can be produced through a conventional electrolytic electrification system. That is, a drum and an anode functioning as a cathode are provided in a container in which an electrolyte is continuously supplied, and an electric current is applied between the drum and the anode so that the electrolyte can intervene therebetween. At this time, the electrolytic copper foil is electrodeposited on the surface of the drum while the drum is rotating, and can be wound up through the guide roll. The electrolytic solution may be a copper electrolytic solution containing copper ion, sulfuric acid, chlorine, and an organic additive. The organic additive may be a thiourea compound or a cellulose compound. The electrolytic solution may include 70 to 100 g / L of copper ions, 70 to 100 g / L of sulfuric acid, 10 ppm or less of chlorine, and 5 ppm or less of each organic additive.

The thiourea compound can improve the production stability and strength of an electrolytic copper foil, and can be used in combination with other additives such as diethylthiourea, ethylenethiourea, acetylenethiourea, dipropylthiourea, N-trifluoroacetylthiourea, N-ethyl thiourea, N-cyanoacetylthiourea, N-allylthiourea, o-tolylthiourea, N, N'-butylene thiourea, thiazolidinethiol, 4-thiazolinethiol, 4-methyl-2-pyrimidinethiol (4 -methyl-2-pyrimidinethiol), 2-thiouracil, or a combination thereof, but is not limited thereto, and any thiourea-based compound that can be used as an additive in the art can be used.

In addition, the cellulose compound may be added as a preparation for achieving stable low-lightness, and may be, but not limited to, hydroxyethyl cellulose (HEC), carboxymethyl cellulose, or a combination thereof. Any additives conventionally used as additives for electrolytic copper foil can be used without limitation. In addition, a sulfide-based compound and a high-molecular-weight nitride may be further added to the electrolytic solution.

The temperature of the copper electrolytic solution used in the production of the electrolytic copper foil according to an embodiment of the present invention may be 40 to 60 ° C, and the current density used in the manufacturing process may be 30 to 60 A / dm ² .

The electrolytic copper foil according to an embodiment of the present invention may further include a purification process such as carbon filtration, diatomite filtration, and hydrogen peroxide addition so as to minimize organic impurities in the electrolytic solution.

Further, the electrolytic copper foil may be selectively subjected to surface treatment. In an embodiment of the present invention, the electrolytic copper foil may be subjected to a chromate treatment on the surface through an immersion process using a rust preventive solution containing chromic acid as a main component, thereby further improving the moisture resistance and heat resistance.

Another aspect of the present invention provides a current collector for a lithium secondary battery manufactured using an electrolytic copper foil having a half-value width after the heat treatment maintained at 97% or more of a room temperature half-value width. Since the current collector is made of the electrolytic copper foil as described above, not only high mechanical strength can be provided even after the heat treatment, but also volume change of the electrode active material can be easily accommodated.

Another aspect of the present invention provides a lithium secondary battery comprising a current collector produced using an electrolytic copper foil having a half-width after heat treatment maintained at 97% or more of a half-value full width at half maximum. The lithium secondary battery according to the present invention can provide improved lifetime characteristics and stable high-efficiency characteristics by employing a negative electrode including a current collector made of the electrolytic copper foil described above, and can exhibit excellent lifetime characteristics particularly at high temperatures.

The lithium secondary battery includes a negative electrode; anode; And an electrolyte disposed between the anode and the cathode.

The negative electrode comprises the above-described current collector; And a negative electrode active material layer disposed on at least one side of the current collector, and the negative electrode active material layer may include a negative electrode active material, a binder, and a conductive material.

The negative electrode active material may be a non-carbon-based material. For example, the negative electrode active material may be at least one selected from the group consisting of a lithium-alloyable metal, an alloy of lithium-alloyable metal and another metal, an oxide of lithium-alloyable metal, a transition metal oxide, . ≪ / RTI >

The lithium-alloyable metal may be at least one selected from the group consisting of Si, Sn, Al, Ge, Pb, Bi, Si-Y alloys (Y is an alkali metal, an alkaline earth metal, a Group 13-16 element, a transition metal, a rare earth element, , Not Si), a Sn-Y alloy (Y is an alkali metal, an alkaline earth metal, a Group 13 element, a transition metal, a rare earth element, or a combination element thereof, but not Sn). The element Y may be at least one element selected from the group consisting of Mg, Ca, Sr, Ba, Ra, Sc, Y, Ti, Zr, Hf, Rf, V, Nb, Ta, Db, Cr, Mo, W, Sg, Pb, Ru, Os, Hs, Rh, Ir, Pd, Pt, Cu, Ag, Au, Zn, Cd, B, Al, Ga, In, Ge, P, As, Sb, Bi, Po, or a combination thereof.

The transition metal oxide may be lithium titanium oxide, vanadium oxide or lithium vanadium oxide, and the non-transition metal oxide may be SnO ₂ or SiO _x (0 <x <2), but is not limited thereto. In particular, the negative electrode active material may be at least one selected from the group consisting of Si, Sn, Pb, Ge, Al, SiO _x (0 <x ≦ 2), SnO _y (0 <y ≦ ₂ ), Li ₄ Ti ₅ O ₁₂ , TiO ₂ , LiTiO ₃ , Li ₂ Ti ₃ O ₇ , but it is not limited thereto, and any non-carbon anode active material may be used as long as it is used in the related art.

Also, a composite of the non-carbon based negative active material and the carbon-based material may be used, and in addition to the non-carbon based material, a carbon-based negative active material may be additionally included. The carbon-based material may be crystalline carbon, amorphous carbon, or a mixture thereof. The crystalline carbon may be graphite such as natural graphite or artificial graphite in the form of non-shaped, flake, flake, spherical or fibrous type, and the amorphous carbon may be a soft carbon (soft carbon) , Hard carbon, mesophase pitch carbide, or calcined coke, but is not limited thereto.

As the conductive material, metal powders such as acetylene black, Ketjen black, natural graphite, artificial graphite, carbon black, carbon fiber, copper, nickel, aluminum and silver, metal fibers and the like can be used. May be used alone or in combination of two or more. However, the conductive material is not limited thereto, and any conductive material may be used as long as it can be used as a conductive material in the related art. In addition, the above-described crystalline carbon-based material can be added as a conductive material.

Examples of the binder include vinylidene fluoride / hexafluoropropylene copolymer, polyvinylidene fluoride (PVDF), polyacrylonitrile, polymethyl methacrylate, polytetrafluoroethylene and mixtures thereof, or styrene butadiene rubber type polymer But are not limited to, and can be used as long as they can be used as bonding agents in the art.

The negative electrode can be produced by the following method. First, a negative electrode active material composition containing a negative electrode active material, a conductive material, a binder and a solvent is prepared, and the negative electrode active material composition is coated directly on the metal current collector to produce a negative electrode plate. Alternatively, the negative electrode active material composition may be cast on a separate support, and then the film peeled off from the support may be laminated on the metal current collector to produce a negative electrode plate. The negative electrode is not limited to the above-described form, but may be in a form other than the above-described form.

As the solvent, N-methylpyrrolidone, acetone, water or the like may be used, but not limited thereto, and any solvent which can be used in the technical field can be used. The content of the negative electrode active material, the conductive material, the binder, and the solvent is generally used in a lithium battery, and one or more of the conductive material, the binder and the solvent may be omitted depending on the use and configuration of the lithium secondary battery.

The anode can be prepared by the following method. First, a cathode active material composition in which a cathode active material, a conductive material, a binder, and a solvent are mixed is prepared, and the cathode active material composition is coated directly on the metal current collector and dried to produce a cathode plate. Alternatively, the cathode active material composition may be cast on a separate support, and then the film peeled from the support may be laminated on the metal current collector to produce a cathode plate.

The positive electrode active material may include at least one selected from the group consisting of lithium cobalt oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, lithium iron phosphate, and lithium manganese oxide. However, May be used. For example, LiNiO ₂ , LiCoO ₂ , LiMn _x O _x (x = 1, 2), LiNi _{1 - x} Mn _x O ₂ (0 <x <1), LiNi _{1 - x - y} Co _x Mn _y O ₂ (0? X? 0.5, 0? Y? 0.5), LiFeO ₂ , V ₂ O ₅ , TiS, MoS and the like can be used. The conductive material, the binder and the solvent in the positive electrode active material composition may be the same as those used in the negative electrode active material composition. It is also possible to add a plasticizer to the cathode active material composition and / or the anode active material composition to form pores inside the electrode plate.

A separator may be inserted between the positive electrode and the negative electrode. The separator is usable as long as it is commonly used in a lithium battery. A material having low resistance against the ion movement of the electrolyte and excellent in the ability to impregnate the electrolyte may be used. For example, glass fiber, polyester, Teflon, polyethylene, polypropylene, polytetrafluoroethylene (PTFE) or a combination thereof, may be in the form of nonwoven fabric or woven fabric. As the lithium ion battery, a windable separator such as polyethylene or polypropylene can be used as a non-limiting example.

The above separator can be produced by the following method. A separator composition may be prepared by mixing a polymer resin, a filler, and a solvent, and the separator composition may be directly coated on the electrode and dried to form a separator. Alternatively, after the separator composition is cast and dried on a support, a separator film peeled from the support may be laminated on the electrode to form a separator.

The polymer resin used in the production of the separator is not particularly limited, and any of the materials used for the binder of the electrode plate may be used. For example, vinylidene fluoride / hexafluoropropylene copolymer, polyvinylidene fluoride (PVDF), polyacrylonitrile, polymethyl methacrylate or mixtures thereof may be used.

The electrolyte disposed between the anode and the cathode may be an organic electrolyte. In addition, the electrolyte may be a solid. The solid electrolyte may be boron oxide or lithium oxynitride, but is not limited thereto and may be used as long as it can be used as a solid electrolyte in the art. The solid electrolyte may be formed on the cathode by a method such as sputtering.

The organic electrolytic solution may be prepared by dissolving a lithium salt in an organic solvent. The organic solvent may be any organic solvent which can be used in the art. Examples of the organic solvent include, but are not limited to, propylene carbonate, ethylene carbonate, fluoroethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, methyl isopropyl carbonate, Propyl carbonate, dibutyl carbonate, benzonitrile, acetonitrile, tetrahydrofuran, 2-methyltetrahydrofuran, gamma -butyrolactone, dioxolane, 4-methyldioxolane, N, Dimethylformamide, acetamide, dimethylsulfoxide, dioxane, 1,2-dimethoxyethane, sulfolane, dichloroethane, chlorobenzene, nitrobenzene, diethylene glycol, dimethyl ether or mixtures thereof.

The lithium salt is selected from the group consisting of LiPF ₆ , LiBF ₄ , LiSbF ₆ , LiAsF ₆ , LiClO ₄ , LiCF ₃ SO ₃ , Li (CF ₃ SO ₂ ) ₂ N, LiC ₄ F ₉ SO ₃ , LiAlO ₂ , LiAlCl ₄ , _x F _{2x + 1} SO ₂ ) (C _y F _{2y + 1} SO ₂ ) (where x and y are natural numbers), LiCl, LiI or mixtures thereof, but not limited thereto, Anything that can be used can be used.

Hereinafter, the present invention will be described in detail with reference to examples. However, these examples are intended to further illustrate the present invention, and the scope of the present invention is not limited to these examples.

Example  : An electric boat  Produce

Example  One

In order to produce an electrolytic copper foil by electrolysis, a debubbling machine in which a DSE (Dimensionally Stable Electrode) and a titanium cathode drum opposed to each other was used, and the temperature of the copper electrolytic solution was maintained at 55 ° C. The current density was 40 A / dm ² , and a copper electrolyte containing 70 g / L of copper ion and 85 g / L of sulfuric acid as the basic composition was used. The copper electrolytic solution was purified through a carbon filter. Chlorine and an organic additive were further added to the copper electrolytic solution, and the compositions of the added chlorine and organic additives are shown in Table 1 below. The electrolytic copper foil prepared above was immersed for 2 seconds in a separate rust prevention bath containing 5 g / L of chromic acid solution to perform chromate treatment on the surface.

Example  2 to 4 and Comparative Example  1 to 4

An electrolytic copper foil was prepared in the same manner as in Example 1, except that the composition of the copper electrolytic solution was changed as shown in Table 1 below.

Abbreviations in Table 1 mean the following compounds.

HEC: Hydroxyethyl cellulose

TU: Thiourea

Experimental Example  One : An electric boat  Property evaluation

1-1. X-ray diffraction analysis ( XRD ; X-ray diffraction)

X-ray diffraction analysis of the electrolytic copper foil prepared in Examples 1 to 4 and Comparative Examples 1 to 4 was carried out using a Bruker D8 DISCOVER at a diffraction angle 2θ = 30-100 °, Theta was scanned at a rate of 2 DEG / min using theta-2-Theta as a scanning axis. The scanning was performed with Cu K? Radiation at 40 kV and 40 mA at 1.5406 A wavelength. The electrolytic copper foil after heat treatment at 130 占 폚 for 10 minutes was subjected to X-ray diffraction analysis in the same manner as described above, and the half-width of the peak appearing on the (111) crystal face of the electrolytic copper foil in the X-ray diffraction spectrum was calculated Respectively. The results are shown in Table 1 above. The X-ray diffraction spectrum of the electrolytic copper foil prepared in Example 1 at room temperature and after heat treatment (at 130 DEG C for 10 minutes) is shown in Figs. 1 and 2, respectively.

1-2. Tensile strength measurement

The tensile tests of the electrolytic copper foils prepared in Examples 1 to 4 and Comparative Examples 1 to 4 were conducted according to the IPC-TM-650 standard. The maximum tensile strength measured at room temperature was referred to as room temperature tensile strength, and the tensile strength was measured in the same manner as above using an electrolytic copper foil after heat treatment at 130 占 폚 for 10 minutes and recorded at high temperature tensile strength (Table 1).

1-3. Surface roughness ( Rz ) And Elongation  Measure

The surface roughness Rz of the electrolytic copper foil prepared in Examples 1 to 4 and Comparative Examples 1 to 4 was measured according to the JIS B0601-1994 standard and the elongation of the electrolytic copper foil was performed according to the IPC-TM-650 standard. Table 2 shows the results.

division Surface roughness (μm) Elongation (%) Example 1 1.6 8.1 Example 2 1.6 7.5 Example 3 1.2 5.1 Example 4 1.9 10.5 Comparative Example 1 2.7 3.4 Comparative Example 2 2.4 8.2 Comparative Example 3 2.6 4.2 Comparative Example 4 1.7 7.9

As a result of evaluation of the physical properties of the electrolytic copper foil produced in the above examples, the half width and the tensile strength after heat treatment were 97% or more and 90% or more, respectively, with respect to the room temperature half width and the room temperature tensile strength , It was confirmed that the electrolytic copper foil which can keep the high strength property constant at high temperature treatment can be manufactured. Further, it was confirmed that wrinkles were not generated on the electrolytic copper foil and the warpage was relaxed, thereby making it possible to produce an electrolytic copper foil which does not cause heat treatment or breakage due to volume change due to heat treatment. That is, from the above results, it can be seen that the electrolytic copper foil can endure the volume change and heat generation phenomenon of the lithium secondary battery, the capacity and performance can be stably maintained, and the efficiency and lifetime characteristics of the battery including the current collector made of the electrolytic copper foil can be improved Can contribute.

The present invention has been described with reference to the preferred embodiments. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. Therefore, the disclosed embodiments should be considered in an illustrative rather than a restrictive sense. The scope of the present invention is defined by the appended claims rather than by the foregoing description, and all differences within the scope of equivalents thereof should be construed as being included in the present invention.

Claims (7)

An electrolytic copper foil for a lithium secondary battery current collector,
The full width at half maximum (FWHM) of the diffraction peak with respect to the (111) crystal face in the X-ray diffraction spectrum of the electrolytic copper foil was 0.18 to 0.35 ° and the full width at half maximum after heat treatment at 130 ° C for 10 minutes And is maintained at 97% or more of the room temperature half value width. Claim 1, wherein the room temperature tensile strength of the electrolytic copper foil is 45 to 70 kgf / mm ² in the , And the tensile strength after heat treatment at 130 占 폚 for 10 minutes is 90% or more of the tensile strength at room temperature. The electrolytic copper foil according to claim 1, wherein the electrolytic copper foil has an elongation of 2 to 20%. The electrolytic copper foil according to claim 1, wherein a surface roughness Rz of the matte side and a shiny side of the electrolytic copper foil is 2.0 m or less. The electrolytic copper foil according to claim 1, wherein the electrolytic copper foil has a thickness of 5 to 20 μm. A current collector for a lithium secondary battery manufactured using the electrolytic copper foil for a lithium secondary battery current collector according to claim 1. A lithium secondary battery comprising a current collector produced by using an electrolytic copper foil for a lithium secondary battery current collector according to claim 1.

Images