WO2017018655A1 - Electrolytic copper foil for lithium secondary battery and lithium secondary battery comprising same - Google Patents

Abstract

An electrolytic copper foil for a lithium secondary battery, according to one embodiment of the present invention, has a curl indicator (C) value of zero to 4.0, the curl indicator (C) value defined as 1.21ΔR+1.12ΔCr+0.01ΔG, wherein the ΔR corresponds to an absolute value of a difference between luminance measured on a first surface of the electrolytic copper foil for a lithium secondary battery and luminance measured on a second surface of the electrolytic copper foil for a lithium secondary battery, the ΔCr corresponds to an absolute value of a difference between an electrodeposit amount of chrome forming an anti-corrosion layer formed on the first surface of the electrolytic copper foil for a lithium secondary battery and an electrodeposit amount of chrome forming an anti-corrosion layer formed on the second surface of the electrolytic copper foil for a lithium secondary battery, and the ΔG corresponds to an absolute value of a difference between a gloss level measured on the first surface of the electrolytic copper foil for a lithium secondary battery and a gloss level measured on the second surface of the electrolytic copper foil for a lithium secondary battery.

Description

Electrolytic copper foil for lithium secondary battery and lithium secondary battery comprising same

The present invention relates to an electrolytic copper foil for a lithium secondary battery and a lithium secondary battery including the same. More specifically, a curl indicator (curl indicator) as a variable which is a main factor for generating curl of copper foil is limited to a certain range, thereby generating curl. It relates to an electrolytic copper foil for a minimized lithium secondary battery and a lithium secondary battery comprising the same. This application claims the priority based on Korean Patent Application No. 10-2015-0104779 filed on July 24, 2015 and Korean Patent Application No. 10-2016-0063598 filed on May 24, 2016, All content disclosed in the specification and drawings of an application is incorporated in this application.

If a certain level of curl is generated in the electrolytic copper foil for a lithium secondary battery, wrinkles may occur in a battery manufacturing process, and when wrinkles are intensified, overlap may occur. Such wrinkles and overlap may occur in lithium. It may become a fatal defect in manufacture of the electrolytic copper foil for secondary batteries.

Accordingly, in the production of the electrolytic copper foil for lithium secondary batteries, it is usually necessary to manage the curl at a level of about 7 mm or less.

On the other hand, the cause of the curl is the difference between the stress and surface characteristics generated on the shiny surface (shiny surface) having a relatively high glossiness and the matte surface having a relatively low gloss of both surfaces of the copper foil Is generated accordingly.

For example, due to such a difference in stress and surface characteristics, M surface curl is generated when compressive stress is applied toward the mat surface, while S surface curl is generated when compressive stress is applied to the shiny surface.

Therefore, in order to reduce the curl generation of the copper foil below a certain level, it is necessary to find factors that have a particularly large influence on the curl of the copper foil among the surface properties of both surfaces of the copper foil, and control their values within a certain level range.

The present invention has been made in view of the above technical problem, and finds factors influencing the curl characteristics of an electrolytic copper foil for a lithium secondary battery and controls the values thereof within a predetermined range to curl the manufacturing process of the electrolytic copper foil for a lithium secondary battery. It is an object of the present invention to minimize the generation amount.

However, the technical problem to be achieved by the present invention is not limited to the above-described problem, another technical problem not mentioned above will be clearly understood by those skilled in the art from the description of the invention described below.

The present inventors have conducted studies to achieve the above technical problem, and found that several factors have a great influence on the curl characteristics of the electrolytic copper foil for lithium secondary batteries, and the curl indicator using these factors as variables. It was found that the amount of curl change of the electrolytic copper foil for a lithium secondary battery can be controlled to a desired level by limiting) to a certain range.

The electrolytic copper foil for lithium secondary batteries according to an embodiment of the present invention is an electrolytic copper foil for lithium secondary batteries, wherein a Curl index (C) value defined as 1.21ΔR + 1.12ΔCr + 0.01ΔG is 0 or more and 4.0 or less, and the ΔR is the lithium. It corresponds to an absolute value of the difference in roughness measured on the first surface and the second surface of the electrolytic copper foil for secondary batteries, wherein ΔCr is the electrodeposition amount of chromium forming a chromium layer formed on the first surface of the lithium secondary battery electrolytic copper foil. And the absolute value of the difference in the electrodeposition amount of chromium forming the chromium layer formed on the second surface, wherein ΔG is the difference between the glossiness measured on the first surface of the electrolytic copper foil for lithium secondary batteries and the glossiness measured on the second surface It corresponds to an absolute value.

The roughness measured on each of both surfaces of the copper secondary battery foil may be 0.2 ㎛ to 2.5 ㎛.

Each electrodeposition amount of chromium forming a chromium layer formed on both surfaces of the copper secondary battery foil may be 1.0 mg / m ^{2 or} more.

Glossiness measured on each of both surfaces of the copper secondary battery foil may be 10GU to 450GU.

The ΔR may be 0 or more and 2.0 μm or less.

The ΔCr may be 0 or more and 3.5 mg / m ² or less.

The ΔG may be 0 or more and 350GU or less.

The lithium secondary battery copper foil may have a thickness of about 4 μm to about 35 μm.

On the other hand, the lithium secondary battery according to an embodiment of the present invention, the lithium secondary battery electrolytic copper foil according to an embodiment of the present invention is applied as a negative electrode current collector.

According to an aspect of the present invention, the amount of curl generated in the copper foil in the manufacturing process of the electrolytic copper foil for lithium secondary battery can be suppressed to below the reference value, thereby preventing the occurrence of wrinkles and overlap in the copper foil in the manufacturing process of the lithium secondary battery. It becomes possible.

The following drawings attached to this specification are illustrative of the preferred embodiments of the present invention, and together with the detailed description of the invention to serve to further understand the technical spirit of the present invention, the present invention is a matter described in such drawings It should not be construed as limited to.

1 is a cross-sectional view showing an electrolytic copper foil for a lithium secondary battery according to an embodiment of the present invention.

2 is a cross-sectional view showing a state in which chromium layers are formed on both surfaces of an electrolytic copper foil for a lithium secondary battery according to an embodiment of the present invention.

3 and 4 are photographs showing a curl measurement method for an electrolytic copper foil for a lithium secondary battery according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, terms or words used in the present specification and claims should not be construed as being limited to the common or dictionary meanings, and the inventors should properly explain the concept of terms in order to best explain their own invention. Based on the principle that can be defined, it should be interpreted as meaning and concept corresponding to the technical idea of the present invention. Therefore, the embodiments described in the specification and the drawings shown in the drawings are only some of the most preferred embodiments of the present invention and do not represent all of the technical spirit of the present invention, various modifications that can be replaced at the time of the present application It should be understood that there may be equivalents and variations.

First, an electrolytic copper foil for a lithium secondary battery according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2.

1 is a cross-sectional view showing an electrolytic copper foil for a lithium secondary battery according to an embodiment of the present invention, Figure 2 is a cross-sectional view showing a state in which antirust layers are formed on both sides of the electrolytic copper foil for a lithium secondary battery according to an embodiment of the present invention.

1 and 2, the electrolytic copper foil 1 for a lithium secondary battery according to an exemplary embodiment of the present invention has a thickness of about 4 μm to 35 μm, and is preferably used as a negative electrode current collector of a lithium secondary battery. That is, it is preferable that an electrolytic copper foil is used as a negative electrode collector couple | bonded with a negative electrode active material in a lithium secondary battery.

On the other hand, in the manufacture of a lithium secondary battery, a foil made of aluminum (Al) is generally used as a positive electrode current collector combined with the positive electrode active material.

Therefore, in this invention, the case where the said electrolytic copper foil 1 for lithium secondary batteries corresponds to the negative electrode electrical power collector applied to a lithium secondary battery is demonstrated as an example.

The stress applied to the electrolytic copper foil 1 for lithium secondary batteries is determined by the surface shape, glossiness, and chromium electrodeposition amount of the copper foil. Surface shape and glossiness are closely related to the crystal structure and grain size of copper foil.

If the grain size is fine and crystals are formed in a circular structure, the surface of the electrolytic copper foil for lithium secondary batteries 1 has low roughness and high gloss. On the other hand, when the grain size is large and has a columnar structure, relatively high roughness and low gloss are achieved. You have a degree.

In general, compressive stress is applied to the side having the low roughness and high glossiness in both surfaces of the electrolytic copper foil 1 for lithium secondary battery, and curl occurs in the compressive stress side.

In addition, curling occurs in the electrolytic copper foil 1 for lithium secondary batteries due to the difference in electrodeposition amount of chromium constituting the rustproof layer 2 formed on both surfaces. That is, the compressive stress is applied to the greater amount of chromium deposition on both surfaces of the electrolytic copper foil 1 for lithium secondary battery, and curling occurs on the surface.

Therefore, in order to reduce curling of the electrolytic copper foil 1 for lithium secondary batteries, rust preventives are formed on both surfaces of the copper foil for rust prevention as well as surface roughness and glossiness related to grain size and crystal structure of the lithium secondary battery electrolytic copper foil 1. Even the amount of chromium deposited in the layer 2 should be taken into account.

In the present invention, considering the difference in all three physical properties measured on both sides of the electrolytic copper foil (1) for the lithium secondary battery, by using the curl index (C) corresponding to the index indicating the degree of curl generated in the copper foil Indicates the degree of curling.

Here, the Curl index (C) is an average roughness measured on both sides of the lithium secondary battery electrolytic copper foil (1), that is, the difference in surface roughness, rustproof layer formed on both sides of the lithium secondary battery electrolytic copper foil (1) for rust prevention ( 2) The index corresponds to the difference in electrodeposition amount of chromium (Cr) and the difference in glossiness measured on both sides of the electrolytic copper foil for lithium secondary batteries (1).

The curl indicator C is defined as follows:

C = 1.21ΔR + 1.12ΔCr + 0.01ΔG (where ΔR is the absolute value of the difference in surface roughness measured at the first side 1a and the second side 1b, ΔCr is the first side 1a and the second side) (1b) The absolute value of the difference of electrodeposition amount of chromium which forms the rustproof layer 2 formed in each, (DELTA) G corresponds to the absolute value of the glossiness difference measured in the 1st surface 1a and the 2nd surface 1b. )

In the electrolytic copper foil 1 for a lithium secondary battery according to an exemplary embodiment of the present invention, the curl index (C) value indicating curl characteristics is limited to 0 or more and 4.0 or less in order to minimize curl generation.

When the curl index (C) value exceeds 4.0, curl of a value larger than the value to be limited for use as a negative electrode current collector of a secondary battery is generated, making it difficult to apply copper foil as a negative electrode current collector of a lithium secondary battery. do.

The three parameters constituting the Curl Index (C) formula are different in units, but in terms of surface roughness difference (ΔR), in μm units, in case of chromium deposition amount (ΔCr), in mg / m ² units, and in glossiness difference. In the case of (ΔG), the Curl index (C) value is obtained by calculating values based on GU (Glossy Unit) units and adding the values together except for units.

On the other hand, the lithium secondary battery electrolytic copper foil (1), in order to obtain the desired curl characteristics, the value of the curl index (C) can be limited within a certain range, preferably, each parameter constituting the curl index (C) ( ΔR, ΔCr, ΔG) may also be limited within a range.

First, it is preferable that ΔR which is the absolute value of the difference in surface roughness measured on both surfaces (first surface and second surface) of the electrolytic copper foil 1 for lithium secondary batteries is 0 or more and 2.0 µm or less. When the ΔR exceeds 2.0 μm, curling in excess of the reference value occurs toward the side where the roughness of both sides of the copper foil is lower, making it difficult to commercialize.

Next, in the electrolytic copper foil 1 for lithium secondary batteries, ΔCr, which is the absolute value of the difference in the electrodeposition amount of chromium forming the rustproof layer 2 formed on both surfaces (first and second surfaces), is 0 to 3.5 mg / it is preferably not more than ² m. When the ΔCr exceeds 3.5 mg / m ² , curling occurs at a level exceeding a reference value toward the side where the amount of electrodeposition is greater among both sides of the copper foil, making it difficult to commercialize.

Finally, it is preferable that ΔG, which is the absolute value of the difference in glossiness measured on both surfaces (first and second surfaces) of the electrolytic copper foil 1 for lithium secondary batteries, becomes 0 or more and 350GU or less. When the ΔG exceeds 350GU, curls exceeding the reference value are generated toward the surface showing higher glossiness of both surfaces of the electrolytic copper foil, making it difficult to commercialize.

On the other hand, the lithium secondary battery electrolytic copper foil (1), it is preferable that the roughness (that is, both surface roughness) measured on the first surface and the second surface, respectively, is approximately 0.2㎛ to 2.5㎛ on the basis of Rz (ten point average roughness). .

When the roughness of the two sides is less than 0.2 μm, there is a problem in that the adhesion between the electrolytic copper foil and the active material is lowered. When the adhesion decreases between the electrolytic copper foil and the active material, the risk of deactivation of the active material is increased during the use of the lithium secondary battery. .

On the contrary, when the roughness of both sides exceeds 2.5 μm, the uniformity of the active material may not be uniformly applied to the surface 1a of the electrolytic copper foil due to the high roughness, and thus the adhesion may be lowered. If not, the discharge capacity retention rate of the manufactured lithium secondary battery may decrease.

In addition, the lithium secondary battery electrolytic copper foil 1 according to an embodiment of the present invention, it is preferable that the glossiness (that is, both sides glossiness) measured on each of the first and second surfaces is approximately 10GU or more and 450GU or less. Do.

When the two-sided glossiness is less than 10GU or more than 450GU, an error may occur in the copper foil sensing during coating of the two-side negative electrode material pattern in the battery manufacturing process.

In addition, it is electrolytic copper foil for a lithium secondary battery according to an embodiment of the present invention, the first surface and the that the rust-preventive layer (2) Cr deposition amount is 1.0mg / m ² or less than 4.5mg / m ² of which is coated on the second surface desirable.

When if the amount is less than 1.0mg / m ² the amount of Cr deposition of electrolytic copper foil surface is easily oxidized due to air in the atmosphere can not be used as a secondary battery, a copper foil, exceeding 4.5mg / m ^2, the electrolytic copper foil and between the negative electrode active material Adhesion decreases.

<Examples and Comparative Examples>

Hereinafter, the characteristics of the present invention will be described more clearly by preparing an electrolytic copper foil of an example satisfying the characteristics of the present invention and a comparative example, and comparing the physical properties between the electrolytic copper foils of this example and the comparative example.

An electrolytic copper foil for a lithium secondary battery according to an embodiment and a comparative example is manufactured by using a milling machine having a structure including a positive electrode plate positioned at a predetermined interval with respect to a rotating drum and a drum in an electrolytic cell.

Electrolytic copper foil according to an embodiment of the present invention is added to the additive consisting of 2 ~ 16mg / L gelatin and 2 ~ 16mg / L HEC in copper sulfate containing 50 ~ 100g / L copper, 50 ~ 150g / L sulfuric acid It can be produced by electrodepositing copper foil on the drum of the above-mentioned machine by applying a current density of approximately 10 ASD to 80 ASD to one electrolyte.

In addition, it is possible to minimize the difference in glossiness and roughness of both surfaces of the copper foil by giving a slope to the applied current to give a difference in the current density of the initial plating and the current density of the final plating. That is, the current density of the initial plating is preferably set to approximately 1.5 times or more higher than the current density of the final plating. Here, the current density of the initial plating refers to the current density applied for 2 to 5 seconds, which is the time when the core of the copper plating is generated during the pulverization process, and the current density of the final plating refers to the current density of the initial plating except for the current density. It means the current density at the time of plating. Further, discontinuous control is made so that the current density of the initial plating is 1.5 times larger than the current density of the final plating. That is, the current control is performed by the current density of the initial plating, and when the final plating time is reached, the current control is performed so that the current density drops continuously to 1.5 times or less.

In addition, the concentration of the pre-treated electrolytic copper foil (ie, the raw foil) prepared by the above-described raw foil manufacturing process is 0.5 to 1.5 g / L, the concentration of the additive (for example, 2-deoxyribose, etc.) is 1.2 g / L The rust preventive layer 2 of FIG. 2 is formed by immersing the rust preventive solution at a liquid temperature of 20 ° C. to 35 ° C. for 0.5 seconds to 2 seconds to apply chromium rust preventive solution on both sides of the pretreated electrolytic copper foil. At this time, the difference in the amount of chromium deposits of the rust-preventing layer 2 is minimized by appropriately adjusting the concentration of Cr and the concentration of the additive (for example, 2-deoxyribose, etc.) and / or the surface roughness and surface shape of the raw foil. can do.

On the other hand, in the electrolytic copper foil according to the comparative example, the concentration of gelatin and HEC in copper sulfate containing 50 ~ 100g / L copper, 50 ~ 150g / L sulfuric acid is different from the embodiment as shown in Table 1 below, and applied to the electrolyte solution The current density of the current to be in the range of 10ASD to 80ASD, but as shown in Table 1 below, by adjusting the difference between the current density of the initial plating and the current density of the final plating is less than 1.5 times to electrodeposit the copper foil on the drum of the machine I was.

In addition, by immersing the pre-treated electrolytic copper foil (ie, the raw foil) according to the comparative example prepared through the above-mentioned raw material manufacturing process in the rust solution as shown in [Table 1] by rust prevention by applying chromium rust solution on both sides of the pre-treated electrolytic copper foil A layer was formed.

The composition, electrolytic conditions and antirust layer formation conditions of a specific electrolyte solution for milling the electrolytic copper foil according to these Examples and Comparative Examples are as follows.

(1) electrolyte composition and electrolytic conditions

Copper: 75g / L

Sulfuric acid: 100g / L

Electrolyte Temperature: 55 ℃

Current Density of Initial Plating and Current Density of Final Plating: Refer to [Table 1] below

Additive (Gelatin and HEC) Concentrations: See Table 1 below

(2) Condition of forming rustproof layer

Cr concentration of rust preventive solution: 1.0g / L

Additive (2-deoxyribose) concentration of rust preventive solution: See Table 1 below.

Liquid temperature: 20 ℃ ~ 35 ℃

Immersion time: 0.5 second to 2 seconds

division	additive (gelatin) [mg / L]	additive (HEC) [mg / L]	Early plating Current density [ASD]	Current Density of Final Plating [ASD]	Cr [g / L]	2- Deoxyribose [g / L]
Example 1	2.1	2.3	75	40	1.0	1.2
Example 2	2.2	15.9	75	40	1.0	1.2
Example 3	7.5	2.2	65	40	1.0	1.2
Example 4	7.8	15.8	65	40	1.0	1.2
Example 5	15.8	2.3	80	40	1.0	1.2
Example 6	15.8	15.8	80	40	1.0	1.2
Example 7	3.7	4.9	70	40	1.0	1.2
Comparative Example 1	1.9	7.6	75	40	1.0	1.2
Comparative Example 2	16.5	7.4	75	40	1.0	1.2
Comparative Example 3	7.5	1.8	80	40	1.0	1.2
Comparative Example 4	7.4	16.8	80	40	1.0	1.2
Comparative Example 5	7.5	7.6	55	40	1.0	1.2
Comparative Example 6	7.5	7.6	45	40	1.0	1.2
Comparative Example 7	2.1	2.3	65	40	1.0	0
Comparative Example 8	2.1	2.3	80	40	1.0	0

Next, the curl generation level according to the curl index (C) value of the electrolytic copper foils of the Examples and Comparative Examples will be described with reference to Table 2 below.

Surface roughness measurement

In order to measure the surface roughness of the electrolytic copper foil, a surface roughness measuring apparatus (SE1700 manufactured by Kosaka Laboratory Ltd.) was used.

Chromium electrodeposition amount analysis

The chromium electrodeposition amount was measured by dissolving the electrolytic copper foil samples of Examples and Comparative Examples with nitric acid having a concentration of 20% by mass and performing quantitative analysis by atomic absorption method using an atomic absorption spectrophotometer (model: AA240FS) manufactured by VARIAN Corporation.

Gloss measurement

The incidence angle was measured at 60 degrees using Nippon Denshoku Industries Co., Ltd. glossimeter handy gloss meter PG-1 based on JISZ8741.

Curl measurement

As shown in the photograph shown in Figure 3, after cutting the matte surface (crosse) of the relatively low glossiness of both surfaces of the electrolytic copper foil of the Examples and Comparative Examples in the form of a cross of 8cm × 8cm size, and the photo shown in Figure 4 Similarly, measure the heights of the four points that rise sharply as the curl occurs. At this time, the arithmetic mean value of the measured value corresponds to the curl value of the said copper foil.

	thickness [Μm]	Front page Rz [μm]	The second page Rz [μm]	△ R [Μm]	Front page Glossiness [G.U]	The second page Glossiness [G.U]	△ G [G.U]	Front page Cr amount [mg / ㎡]	The second page Cr amount [mg / ㎡]	△ Cr [mg / ㎡]	Curl Index [C]	Curl [mm]
Example 1	6	2.44	0.85	1.59	45	80	35	2.1	1.9	0.2	2.50	2.3
Example 2	6	2.45	0.85	1.60	122	85	37	2.1	1.9	0.2	2.53	6.4
Example 3	6	1.76	0.85	0.91	88	42	46	2.1	1.9	0.2	1.79	6.8
Example 4	6	1.21	0.85	0.36	211	121	90	2.1	1.3	0.8	2.23	6.4
Example 5	6	1.32	0.88	0.44	177	86	91	2	2.5	0.5	2.00	4.2
Example 6	6	0.65	0.88	0.23	362	83	279	2	2.7	0.7	3.85	5.8
Example 7	6	2.01	0.78	1.23	88	87	One	2	2.9	0.9	2.51	6.5
Comparative Example 1	6	2.92	0.85	2.07	32	87	55	2.8	1.9	0.9	4.06	7.5
Comparative Example 2	6	1.21	0.85	0.36	425	73	352	2.1	1.9	0.9	4.18	7.9
Comparative Example 3	6	2.89	0.85	2.04	18	82	64	2.9	1.9	1.0	4.23	8.2
Comparative Example 4	6	0.67	0.85	0.18	467	82	385	1.9	2.1	0.2	4.29	8.3
Comparative Example 5	6	2.88	0.67	2.21	18	82	64	2.9	2.1	0.8	4.21	8.1
Comparative Example 6	6	3.02	0.67	2.35	11	82	71	2.8	2.1	0.7	4.34	8.3
Comparative Example 7	6	2.12	0.88	1.24	89	86	3	4.1	0.5	3.6	5.56	7.9
Comparative Example 8	6	1.45	0.88	0.57	268	86	182	2.2	0.7	1.5	4.19	7.9

Looking at the above [Table 2], when the curl index (C) of the copper foil appears to be 4 or less (Examples 1 to 7), the curl generation amount does not exceed the reference value to 7mm or less, but the curl index (C) exceeds 4 In the case of (comparative examples 1-8), it turns out that the curl generation amount exceeds 7 mm.

In Examples 1 to 7, not only the curl index C of the copper foil was found to be 4 or less, but also C = 1.21ΔR + 1.12ΔCr + 0.01ΔG, provided that ΔR is the first face 1a and the first of the copper foil. ΔCr is the absolute value of the roughness difference measured on the second surface 1b, and ΔG is the absolute value of the difference in electrodeposition amount of chromium constituting the rustproof layer 2 formed on each of the first and second surfaces 1a and 1b. Each of the parameters ΔR, ΔCr and ΔG constituting the curl index C, which is expressed as an absolute value of the difference in glossiness measured on the first side 1a and the second side 1b, also have a preferred range. It can be seen that it does not deviate.

That is, in Examples 1 to 7, it can be seen that ΔR is 2.0 μm or less, ΔCr is 3.5 mg / m ² or less, and ΔG is 350 GU or less.

On the other hand, in Comparative Examples 1 to 7, not only the curl index C of the copper foil exceeds 4, but the respective parameters ΔR, ΔCr, and ΔG constituting the curl index C are preferred ranges. You can see that it is moving away from. In particular, in the case of Comparative Example 8, although the value of the respective parameters ΔR, ΔCr and ΔG constituting the curl index (C) satisfies the numerical value specified in the present invention, the curl index (C) exceeds 4 The amount of curl generated exceeds 7 mm.

As described above, the lithium secondary battery copper foil according to an embodiment of the present invention, as well as the curl indicator (curl indicator) as a variable to the main factors that generate the curl of the copper foil is limited to a certain range, and constitutes the curl indicator Each variable is also limited to a certain range to minimize the occurrence of curl.

Although the present invention has been described above by means of limited embodiments and drawings, the present invention is not limited thereto and will be described below by the person skilled in the art to which the present invention pertains. Of course, various modifications and variations are possible within the scope of the claims.

The present invention relates to an electrolytic copper foil for a lithium secondary battery, which is a negative electrode current collector material applied to a lithium secondary battery, and a lithium secondary battery including the same.

Claims (13)

1. In the electrolytic copper foil for lithium secondary batteries,

   Curl index (C) value defined as 1.21ΔR + 1.12ΔCr + 0.01ΔG is 0 or more and 4.0 or less,

   ΔR corresponds to an absolute value of the illuminance difference measured on the first surface of the electrolytic copper foil for lithium secondary batteries and the illuminance difference measured on the second surface,

   The ΔCr corresponds to an absolute value of the difference between the electrodeposition amount of chromium forming the rustproof layer formed on the first surface of the electrolytic copper foil for lithium secondary batteries and the chromium electrodeposition amount of the chromium forming the rustproof layer formed on the second surface,

   The ΔG corresponds to the absolute value of the difference in glossiness measured on the first surface and the glossiness measured on the second surface of the electrolytic copper foil for lithium secondary batteries.
2. The method of claim 1,

   The surface roughness measured on the first and second surfaces of the electrolytic copper foil for lithium secondary batteries is 0.2 ㎛ to 2.5 ㎛ electrolytic copper foil for each of.
3. The method of claim 1,

   The electrolytic copper foil for a lithium secondary battery a first side and a deposition amount of the chromium forming a rust-preventive layer formed on the second side is a lithium secondary battery, electrolytic copper foil, it characterized in that each of 1.0mg / m ^2, more than 4.5mg / m ² or less of.
4. The method of claim 1,

   The glossiness measured on the first and second surfaces of the electrolytic copper foil for lithium secondary batteries is 10GU to 450GU, respectively.
5. The method of claim 1,

   Said (DELTA) R is 0 or more and 2.0 micrometers or less, The electrolytic copper foil for lithium secondary batteries characterized by the above-mentioned.
6. The method of claim 1,

   The ΔCr is from 0 to 3.5mg / m ² or less, characterized in that the lithium secondary battery electrolytic copper foil.
7. The method of claim 1,

   The ΔG is 0 or more and 350GU or less, the electrolytic copper foil for lithium secondary batteries.
8. The method of claim 5,

   The ΔG is 0 or more and 350GU or less, the electrolytic copper foil for lithium secondary batteries.
9. The method of claim 8,

   The ΔCr is from 0 to 3.5mg / m ² or less, characterized in that the lithium secondary battery electrolytic copper foil.
10. The method of claim 5,

    The ΔCr is from 0 to 3.5mg / m ² or less, characterized in that the lithium secondary battery electrolytic copper foil.
11. The method of claim 7, wherein

    The ΔCr is from 0 to 3.5mg / m ² or less, characterized in that the lithium secondary battery electrolytic copper foil.
12. The method of claim 1,

    The thickness of the said electrolytic copper foil for lithium secondary batteries is 4 micrometers-35 micrometers, The electrolytic copper foil for lithium secondary batteries.
13. A lithium secondary battery to which the electrolytic copper foil for lithium secondary batteries according to any one of claims 1 to 12 is applied as a negative electrode current collector.

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