KR20170126775A - Electrolytic Copper Foil Having Low Surface Roughness, Method for Manufacturing The Same, Flexible Copper Clad Laminate Comprising The Same, Anode Comprising The Same, and Secondary Battery Comprising The Same - Google Patents

Abstract

Disclosed are an electrolytic copper foil having low surface roughness, a method for manufacturing the same, a flexible copper clad laminate having excellent peeling strength between the electrolytic copper foil and a nonconductive polymer membrane, a negative electrode having excellent adhesion between the electrolytic copper foil and a negative electrode active material and a secondary battery having excellent charging and discharging capacity maintenance rates. The electrolytic copper foil of the present invention comprises: a plurality of nodules arranged on the mat surface; and a plurality of fine nodules located on at least one surface of the nodules and having the longest diameter of 0.2 m or less.

Description

TECHNICAL FIELD [0001] The present invention relates to an electrolytic copper foil having a low surface roughness, a method for producing the same, a flexible copper-clad laminate film containing the same, a cathode including the same, and a secondary battery comprising the same. The Same, Anode Comprising The Same, and Secondary Battery Comprising The Same}

The present invention relates to an electrolytic copper foil having a low surface roughness and a method for producing the same, and also relates to a flexible copper foil laminated film having excellent peel strength between an electrolytic copper foil and a nonconductive polymer membrane, a negative electrode having excellent adhesion strength between an electrolytic copper foil and a negative active material, To a secondary battery having a discharge capacity retention ratio.

Electronic devices such as notebook computers, mobile phones, PDAs, compact video cameras, and electronic notebooks have become increasingly smaller and lighter, flexible printed circuit boards (TABs) that can be applied to TAB (Tape Automated Bonding) and COF : FPCB) is increasing. As a result, demand for a flexible copper clad laminate (FCCL) used for manufacturing FPCB is also increasing.

The flexible copper foil laminated film is a laminate of a nonconductive polymer film and a copper foil. A flexible printed circuit board can be obtained by selectively removing the copper foil of the flexible copper-clad laminate film and forming a predetermined circuit pattern on the nonconductive polymer membrane.

If the copper foil to be removed when forming the circuit pattern is not completely removed and a part of it remains (i.e., remaining copper exists), a short circuit is caused and the flexible printed circuit board (FPCB) Of course, reduces the yield and reliability of the electronic device to which it is applied.

On the other hand, when the peeling strength between the nonconductive polymer membrane and the copper foil is low, when the copper foil is selectively etched to form a circuit pattern on the nonconductive polymer substrate, the etchant penetrates between the circuit pattern and the non- There is a risk that the circuit pattern peels off from the nonconductive polymer base material.

The flexible copper clad laminate film can be formed by: i) forming a nonconductive polymer film on the copper foil by i) producing a copper foil and then coating or laminating the film or ii) depositing copper on the nonconductive polymer film. Generally, in terms of the peel strength between the nonconductive polymer membrane and the copper foil, the former method can provide a flexible copper-clad laminate film which is superior to the latter method.

However, even in the case of the flexible copper-clad laminate film produced by the former method, the peel strength between the nonconductive polymer film and the copper foil is not satisfactory.

In order to increase the peel strength, it may be considered to increase the surface roughness (R _z ) of the copper foil in contact with the nonconductive polymer membrane. However, as a portable electronic device such as a smart phone is miniaturized, the thickness of a nonconductive polymer membrane such as a polyimide film must be reduced, and the reduction of the thickness of the nonconductive polymer membrane is required to have a low surface roughness (R _z ) ). ≪ / RTI > That is, according to the prior art, if the peeling strength of the copper foil to the nonconductive polymer membrane is increased, the miniaturization of the portable electronic device can not be attained.

Conversely, if the surface roughness (R _z ) of the copper foil is lowered in order to meet the miniaturization of the portable electronic device, there arises a problem that the copper foil is easily peeled off from the nonconductive polymer membrane. Particularly, as electronic equipment is getting smaller and smaller, the angle at which the flexible printed circuit board (FPCB) is folded in the electronic equipment becomes more sharp, and the risk of peeling of the circuit pattern is increasing. The peeling of the circuit pattern due to insufficient peel strength between the nonconductive polymer film and the copper foil lowers the yield, durability and reliability of the flexible printed circuit board (FPCB) itself as well as the electronic equipment to which it is applied.

Meanwhile, the lithium secondary battery includes a negative electrode, and the negative electrode includes a copper foil and a negative electrode active material coated thereon. As the charging and discharging of the lithium secondary battery is repeated, contraction and expansion of the negative electrode active material occur alternately. This causes separation of the copper foil and the negative electrode active material, thereby lowering the charge / discharge capacity retention rate of the lithium secondary battery. In particular, as the bonding strength between the copper foil and the negative electrode active material is weak, the charge / discharge capacity retention rate of the lithium secondary battery is seriously degraded.

Accordingly, it is an object of the present invention to provide an electrolytic copper foil capable of preventing problems caused by limitations and disadvantages of the related art, a manufacturing method thereof, a flexible copper-clad laminated film including the same, a cathode including the same, and a secondary battery comprising the same will be.

One aspect of the present invention is to provide an electrolytic copper foil having a low surface roughness and excellent adhesion between the nonconductive polymer membrane and the negative electrode active material.

Another aspect of the present invention is to provide a method for producing an electrolytic copper foil having a low surface roughness and excellent adhesion to a nonconductive polymer membrane or an anode active material.

Another aspect of the present invention is to provide a flexible copper clad laminated film having an electrolytic copper foil having a low surface roughness not only capable of responding to miniaturization of electronic devices but also having excellent peel strength between a nonconductive polymer membrane and an electrolytic copper foil.

Another aspect of the present invention is to provide a negative electrode having excellent adhesion strength between an electrolytic copper foil and a negative electrode active material.

Another aspect of the present invention is to provide a secondary battery having an excellent charge / discharge capacity retention ratio.

Other features and advantages of the invention will be set forth in the description which follows, or may be learned by those skilled in the art from the description.

According to an aspect of the present invention, there is provided an electrolytic copper foil having a mat surface and a shinny surface opposite thereto, the electrolytic copper foil comprising: a plurality of nodules arranged on the mat surface; And a plurality of micro-nodes located on a surface of at least one of the nodules and having a maximum diameter of 0.2 탆 or less, wherein the longest diameter means a maximum diameter in a direction parallel to the shiny plane And an electrolytic copper foil is provided.

The fine nodules may include at least one of Cu, Ni, Zn, Fe, Cr, and Mo.

The R _z of the matte surface may be 0.8 to 3 탆.

The fine nodules may have a spherical shape or a needle shape.

The thickness of the electrolytic copper foil may be 1 to 70 탆.

The electrolytic copper foil may include a main copper film; A copper nodule layer on the main copper layer, the copper nodule layer including the nodules; A micro-nodule layer on the copper node layer, the micro node layer comprising the micro nodes; And a barrier layer on the fine nodule layer.

Wherein the barrier layer comprises: a first sub-barrier layer on the fine nodal layer; And a second sub-barrier layer on the first sub-barrier layer.

The first sub-barrier layer may comprise zinc or a zinc alloy, and the second sub-barrier layer may comprise chromium.

The surface of the second sub-barrier layer may be modified with a silane coupling agent.

According to another aspect of the present invention, there is provided a method of manufacturing a semiconductor device, comprising: forming a main copper film through electroplating; Forming a copper layer on the main copper layer; And forming a fine nodular layer on the copper nodule layer including a plurality of fine nodules having a maximum diameter of 0.2 탆 or less, wherein the longest diameter means a maximum diameter in a direction parallel to the shiny surface, Wherein the electrolytic copper foil is a copper foil.

The copper seed layer forming step may include the steps of: performing a powdering process to produce nodular nuclei on the main copper film; And performing a capsuling process to stabilize the nodular nucleus.

The powdering process may be performed at a current density of 20 to 50 ASD in a first plating solution maintained at 20 to 30 DEG C, the first plating solution may include 15 to 35 g / L of copper ions, 90 to 210 g / L of sulfuric acid and 0.01 to 5 g / L of additives may be included in the additive. The additive may be Ti, V, Cr, Fe, Co, Mo, W, Ni or a mixture of at least one of them have.

The encapsulation process may be performed at a current density of 5 to 40 ASD in a second plating solution maintained at 40 to 60 DEG C and the second plating solution may include 40 to 60 g / L of copper ions and 90 to 210 g / L of sulfuric acid.

The powdering step and the encapsulating step may be alternately performed two or more times each.

The microdomold layer forming step may be performed at a current density of 5 to 20 ASD in a third plating solution maintained at 20 to 30 DEG C, and the third plating solution may include 7 to 10 g / L of copper ions, 14 to 16 g / L of nickel ions, and 90 to 210 g / L of sulfuric acid.

The method of the present invention may further include the step of forming a barrier layer on the fine nodular layer.

The forming of the barrier layer may include forming a first sub-barrier layer including zinc or a zinc alloy on the micro-nodular layer, And forming a second sub-barrier layer containing chromium on the first sub-barrier layer.

The method of the present invention may further comprise modifying the surface of the second sub-barrier layer with a silane coupling agent.

According to still another aspect of the present invention, there is provided an electrolytic copper foil comprising: the electrolytic copper foil described above; And a nonconductive polymer membrane on the mat surface of the electrolytic copper foil.

According to still another aspect of the present invention, there is provided an electrolytic copper foil comprising: the electrolytic copper foil described above; And a negative electrode active material layer on the mat surface of the electrolytic copper foil.

According to another aspect of the present invention, An electrolyte for providing an environment in which lithium ions can move between the anode and the cathode; And a separator that electrically isolates the anode and the cathode from each other.

The foregoing general description of the present invention is intended to be illustrative of or explaining the present invention, but does not limit the scope of the present invention.

According to the present invention, excellent peel strength between the electrolytic copper foil and the nonconductive polymer membrane can be ensured while maintaining the surface roughness of the electrolytic copper foil at a low level. Therefore, the present invention can not only cope with miniaturization of electronic devices but also can prevent the yield, durability, and reliability of the flexible printed circuit board (FPCB) and the electronic devices to which the flexible printed circuit board (FPCB) is applied from deteriorating due to peeling of the circuit pattern.

Further, according to the present invention, it is possible to prevent the copper part to be removed when the electrolytic copper foil of the flexible copper-clad laminated film is partially etched to form the circuit pattern, without causing the copper part to be completely removed and causing the residue. Therefore, it is possible to prevent a reduction in the yield and reliability of the electronic apparatus due to the short circuit.

Further, since the electrolytic copper foil of the present invention is strongly adhered to the negative electrode active material, separation of the active material from the electrolytic copper foil can be suppressed during charging and discharging of the secondary battery, and as a result, a secondary battery having a high charge / discharge capacity retention rate can be manufactured.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.
1 is a schematic view of an electrolytic copper foil according to the present invention,
2 is an SEM photograph of a mat surface of an electrolytic copper foil according to an embodiment of the present invention,
3 is a SEM photograph of a mat surface of an electrolytic copper foil according to the prior art,
4 is a cross-sectional view of an electrolytic copper foil according to an embodiment of the present invention,
5 is a schematic view illustrating an apparatus for manufacturing an electrolytic copper foil according to an embodiment of the present invention,
6 is a cross-sectional view of a flexible copper-clad laminate film according to an embodiment of the present invention,
7 is a graph of surface roughness (R _z ) of an electrolytic copper foil with respect to a current density applied during a process of forming a fine nodule layer, obtained from Examples and Comparative Examples.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention. Therefore, the present invention encompasses all changes and modifications that come within the scope of the invention as defined in the appended claims and equivalents thereof.

1 is a schematic view of an electrolytic copper foil of the present invention.

As shown in FIG. 1, the electrolytic copper foil 100 of the present invention has a matte surface M and a shiny surface S opposite thereto.

Matte side of electrolytic copper foil 100 of the present invention (M) has a low surface roughness (R _z) (for example, 0.8 to 3.0 ㎛) so the electrolytic copper foil (100) is able to be applied to a thin non-conductive polymer membrane for small electronic devices Lt; / RTI >

2, which is an SEM photograph of a mat surface M of an electrolytic copper foil 100 according to an embodiment of the present invention, an electrolytic copper foil 100 of the present invention is formed by a plurality of nodules (MN) located on the surface of at least one of the plurality of nodules (N) and the nodules (N) and having a maximum diameter of 0.2 mu m or less. The longest diameter of the micro nodes (MN) means the maximum diameter in a direction parallel to the shiny plane (S) of the electrolytic copper foil (100).

When the diameter of the micro nodules MN exceeds 0.2 탆, the surface roughness R _z of the matte surface M of the electrolytic copper foil 100 is so high that it can not be applied to a thin non- The copper of the portion to be removed when the electrolytic copper foil 100 of the flexible copper-clad laminated film is partially etched for forming a circuit pattern is not completely removed and a part thereof remains (that is, Causes a short circuit of the flexible printed circuit board (FPCB). The term "surface roughness (R _z )" means ten-point mean roughness.

When the electrolytic copper foil 100 is used for manufacturing a secondary battery, if the diameter of the micro nodules MN exceeds 0.2 탆, the anode active material may be damaged due to a high surface roughness R _z of the electrolytic copper foil 100 It can not be uniformly coated on the electrolytic copper foil 100. Uneven coating of the negative electrode active material causes partial desorption of the active material from the electrolytic copper foil 100 during charging and discharging of the secondary battery, thereby rapidly lowering the capacity retention rate of the secondary battery and shortening the life of the secondary battery.

In other words, since the micro nodules MN of the present invention have a very small maximum diameter of not more than 0.2 탆, they have little influence on the surface roughness R _z of the mat surface M of the electrolytic copper foil 100, The adhesive strength and peel strength of the electrolytic copper foil 100 to the conductive polymer membrane / negative electrode active material can be remarkably increased.

On the other hand, as illustrated in the SEM photograph of FIG. 3, since the mat surface of the electrolytic copper foil of the prior art includes only the nodules N and does not include the micro nodules MN of the present invention, the nonconductive polymer membrane / The adhesive force and the peel strength between the active material and the electrolytic copper foil are insufficient and the flexible printed circuit board (FPCB) manufactured by the electrolytic copper foil of the prior art has a high risk of peeling off the circuit pattern, and the secondary battery manufactured by the electrolytic copper foil of the prior art, A capacity retention rate and a short life span.

When the fine nodules MN of the present invention having the longest diameter of 0.2 탆 or less are formed on the surface of the nodules N, the increase in the surface roughness of the prior art electrolytic die without the fine nodules is only 5% or less The increase in peel strength was confirmed to be over 30%.

As a result, according to the present invention, the surface roughness (R _z ) of the mat surface M of the electrolytic copper foil 100, which is substantially determined by the nodules N, is kept at a low value of 0.8 to 3.0 탆, The adhesive force and peel strength of the electrolytic copper foil 100 to the nonconductive polymer membrane / negative electrode active material are the same as those of the prior art having the same surface roughness (R _z ) due to the micro nodules MN having a very smallest diameter of 0.2 μm or less It can be significantly improved compared to the electrolytic copper foil. According to an embodiment of the present invention, not only the nodules N but also the nodules MN may have a spherical shape or a needle shape. By having such a shape, the peeling strength can be further increased without raising the roughness.

The fine nodules MN of the present invention may include at least one of Cu, Ni, Zn, Fe, Cr, and Mo.

The thickness of the electrolytic copper foil 100 according to an embodiment of the present invention may be 1 to 70 탆. When the thickness of the electrolytic copper foil 100 is less than 1 占 퐉, wrinkles are generated in the flexible copper foil laminated film when the copper foil laminated film is produced using the electrolytic copper foil 100. [ On the other hand, when the thickness of the electrolytic copper foil 100 exceeds 70 μm, there arises a problem that the copper remains in a portion where copper is selectively removed when an etching process for forming a circuit pattern is performed.

As the thickness of the electrolytic copper foil 100 used as the anode current collector of the lithium secondary battery becomes thinner, the capacity of the secondary battery can be increased by thickly coating the anode active material. Therefore, it is preferable that the electrolytic copper foil 100 used for manufacturing the secondary battery has a thickness of 1 to 20 mu m. If the thickness of the electrolytic copper foil 100 is less than 1 탆, workability in handling is poor and wrinkles and / or tears are frequently caused in the roll-to-roll process. On the other hand, when the thickness of the electrolytic copper foil 100 exceeds 20 μm, there is a limit to increase the capacity of the secondary battery.

Hereinafter, an electrolytic copper foil 100 according to an embodiment of the present invention will be described in detail with reference to FIG.

4, the electrolytic copper foil 100 according to an embodiment of the present invention includes a main copper film 110, a copper nodule layer on the main copper film 110 120, a micro-nodule layer 130 on the copper layer and a barrier layer 140 on the micro-layer 130.

The main copper film 110 is manufactured through electroplating, and has a shiny surface in contact with the rotating cathode drum and a mat surface on the opposite side.

The surface of the main copper film 110 is treated so that the copper nucleus layer 120, the fine nodule layer 130 and the barrier layer 140 are formed on one surface (for example, a matte surface) of the main copper film 110, Or sequentially formed on both surfaces.

The copper module layer 120 includes the nodules N and the microdomell layer 130 includes the micro nodes MN.

The effect of the barrier layer 140 on the physical properties of the mat surface M of the electrolytic copper foil 100 of the present invention is extremely slight. How to form the copper layer 120 and the microdomell layer 130 has a considerable effect on the final physical properties of the copper foil 100. The copper layer 120 and the fine layer 130 The specific method of forming the present invention will be described later.

4, the barrier layer 140 includes a first sub-barrier layer 141 on the micro-nodule layer 130 and a second sub-barrier layer 141 on the first sub- (Not shown).

The first sub-barrier layer 141 is for imparting oxidation resistance, heat resistance and chemical resistance to the electrolytic copper foil 100 and is made of zinc (Zn), zinc alloy, nickel (Ni), iron (Fe), cobalt ), Vanadium (V), and molybdenum (Mo), preferably 3 to 20 mg / m ² of zinc (Zn) or zinc alloy.

The first sub-barrier layer 141 may further include an impurity of 0.05 wt% or less. The impurity may be at least one of phosphorus (P), sulfur (S), carbon (C), oxygen (O), and wheat nitrogen (N).

The second sub-barrier layer 142 prevents chromium (Cr) from being oxidized when the electrolytic copper foil 100 of the present invention is stored for a long period of several months.

The surface of the second sub-barrier layer 142 may be modified with a silane coupling agent. That is, the surface of the second sub-barrier layer 142 may be bonded to the silane coupling agent.

Hereinafter, a method of manufacturing an electrolytic copper foil 100 according to an embodiment of the present invention will be described in detail with reference to FIG.

First, a positive electrode plate 13 and a rotating negative electrode drum 12, which are arranged so as to be spaced apart from each other in an electrolytic solution 11 contained in an electrolytic bath 10, are energized at a current density of 10 to 80 ASD, The main copper film 110 is formed by electrodeposition. The distance between the positive electrode plate 13 and the rotating cathode drum 12 may be 8 to 13 mm.

The electrolytic solution 11 contains 50 to 100 g / L of copper ions, 50 to 150 g / L of sulfuric acid, 17 to 23 ppm of chlorine ions, and an organic additive. The organic additives may be gelatin, hydroxyethyl cellulose (HEC), organic sulfides (e.g., SPS), organic nitrides, thiourea, or a mixture of two or more thereof.

The electrolytic solution 11 may be maintained at 40 to 60 ° C during the main copper film 110 formation step and the flow rate of the electrolytic solution 11 supplied to the electrolytic bath 10 may be 30 to 50 m ³ / Lt; / RTI > It is preferable that the flow rate variation of the electrolytic solution 11 supplied to the electrolytic bath 10 is controlled to be within 2%.

The roughness of the matte surface of the main copper film 110 can be controlled by adjusting the current density, composition and composition ratio of the electrolytic solution.

On the other hand, the roughness of the shiny side of the main copper film 110 depends on the degree of polishing of the surface of the rotating cathode drum 12. According to an embodiment of the present invention, the surface of the rotary cathode drum 12 is polished with an abrasive brush having a grain size of # 800 to # 1500.

Subsequently, a surface treatment for sequentially forming a copper nucleus layer 120 and a fine nucleus layer 130 on the main copper film 110 manufactured through electrolytic plating is performed. The method of the present invention may further include the step of forming a barrier layer 140 on the fine nodule layer 130.

The copper nucleus layer 120 may be formed by sequentially performing a powdering process and a capsuling process.

The powdering process is a process for producing a nodule nucleus on the main copper film 110 for improving the adhesion with the nonconductive polymer film. The process comprises the steps of: providing a current of 20 to 50 ASD in the first plating liquid maintained at 20 to 30 캜; Density < / RTI > The first plating solution may contain 15 to 35 g / L of copper ions, 90 to 210 g / L of sulfuric acid, and 0.01 to 5 g / L of additives, and the additive may include Ti, V, Cr, Fe, Co , Mo, W, Ni, or a mixture of at least one of them or a mixture of two or more of them.

The encapsulation process may be performed at a current density of 5 to 40 ASD in a second plating solution maintained at 40 to 60 캜 for stabilizing the nuclei formed through the powdering process. The second plating solution may contain 40 to 60 g / L of copper ions and 90 to 210 g / L of sulfuric acid. Copper is uniformly deposited through the encapsulation process, so that the nodule nuclei can be further grown or the nodule nucleus can be prevented from falling off.

As illustrated in FIG. 5, the powdering process and the encapsulation process may be performed by sequentially passing the main copper film 110 through the first and second copper plating baths 20 and 30. At this time, the first plating solution for the powder ring process is contained in the first copper plating tank 20, and the second plating solution for encapsulating process is contained in the second plating tank 30.

Alternatively, the powdering process and the encapsulation process may be performed at least two times, alternating with each other.

Before forming the copper nucleus layer 120 on the main copper film 110, impurities (for example, a resin component) and a natural oxide film on the surface of the main copper film 110 Acid cleaning for removal of the acid solution and water cleaning for removing the acidic solution used for the pickling can be sequentially performed. As the acid solution for the pickling process, a hydrochloric acid solution, a sulfuric acid solution, a sulfuric acid-hydrogen peroxide solution, or a mixture of at least two of them may be used. The concentration and temperature of the acidic solution can be adjusted according to the characteristics of the production line.

Subsequently, the main copper film 110, which has sequentially passed through the first and second copper plating tanks 20 and 30, is allowed to pass through the third copper plating tank 40 containing the third plating solution, A micro-nodule layer 130 including a plurality of micro-nodules having a maximum diameter of less than or equal to 탆 is formed on the copper module layer 120. As described above, the longest diameter means the maximum diameter in the direction parallel to the shiny surface.

The third plating solution may be maintained at 20 to 30 캜, and may include 7 to 10 g / L of copper ion, 14 to 16 g / L of nickel ion, and 90 to 210 g / L of sulfuric acid.

The step of forming the microdomell layer 130 may be performed at a current density of 5 to 20 ASD. When the current density of less than 5 ASD is applied, since the micro-nodules (MN) are scarcely generated, it is not expected to sufficiently improve the adhesive force and peel strength with the nonconductive polymer membrane / negative electrode active material. On the other hand, when the current density exceeding 20 ASD is applied, the micro-nodules MN grow excessively and their maximum diameter exceeds 0.2 탆.

As described above, when the diameter of the fine nodules MN exceeds 0.2 탆, the surface roughness R _z of the electrolytic copper foil 100 increases sharply so that it can not be applied to a thin nonconductive polymer membrane for small electronic devices And exceeds 3.0 占 퐉, so that a residual is caused when the electrolytic copper foil 100 is partially etched to form a circuit pattern, causing a short circuit of the flexible printed circuit board (FPCB). In addition, in the case of the secondary battery, since the negative electrode active material is coated on the electrolytic copper foil 100 in a non-uniform manner, the active material is partially separated from the electrolytic copper foil 100 during charging and discharging of the secondary battery, Thereby shortening the lifetime of the battery.

Next, a barrier layer 140 is formed on the fine nodule layer 130.

According to an embodiment of the present invention, the forming of the barrier layer 140 may include forming a first sub-barrier layer 141 including zinc (Zn) or a zinc alloy on the micro-nodule layer 130 And forming a second sub-barrier layer 142 containing chromium (Cr) on the first sub-barrier layer 141.

As described above, the first sub-barrier layer 141 is for imparting oxidation resistance, heat resistance, and chemical resistance to the electrolytic copper foil 100. In the first sub-barrier layer 141, But the present invention is not limited thereto and may include nickel (Ni), iron (Fe), cobalt (Co), vanadium (V), molybdenum (Mo), and the like.

The second sub-barrier layer 142 prevents corrosion of the electrolytic copper foil 100 when it is stored for a long period of several months.

5, the main copper film 110 on which the fine nodule layer 130 is formed is sequentially passed through the zinc plating bath 50 and the chromium plating bath 60 to form the first and second The sub-barrier layers 141 and 142 may be sequentially formed.

The plating solution of the zinc plating bath (50) contains 1 to 5 g / L of zinc ions and can be maintained at 30 to 45 캜. Alternatively, the plating solution contained in the zinc plating bath 50 may further contain at least one of phosphorus (P), sulfur (S), carbon (C), oxygen (O) and wheat nitrogen (N) can do. The plating in the zinc plating bath 50 can be performed at a current density of 1 to 5 ASD.

The plating solution of the chromium plating bath 60 contains 1 to 5 g / L of chromic acid, has a pH of 10 to 12, and can be maintained at 20 to 40 ° C. In addition, plating can be performed at a current density of 0.5 to 4 ASD.

After the second sub-barrier layer 142 is formed, a drying process is performed, and then the electrolytic copper foil 100 is wound on a winder WR.

5, the method of manufacturing an electrolytic copper foil according to the present invention further includes, after the drying step, modifying the surface M of the second sub-barrier layer 142 with a silane coupling agent can do. The silane coupling agent may be an olefin group, an epoxy group, an amino group, or a silane having a mercapto group. The surface modification using the silane coupling agent can be carried out by a dipping method, a showering method, a spraying method, or the like. The surface modification using a silane coupling agent strengthens the adhesive force between the electrolytic copper foil 100 and the nonconductive polymer membrane when producing the flexible copper-clad laminated film.

On the other hand, the surface treatment process for the electrolytic copper foil for the secondary battery may be different from the electrolytic copper foil for the flexible copper foil laminated film. Generally, for use as an electrolytic copper foil for a secondary battery, chromate or electrolytic chromium or silane coupling or BTA (bententriazole) is rust-treated after being applied, but the present invention provides superior performance Unlike the electrolytic copper foil for the flexible copper foil laminated film, the powdering process and the encapsulating process after the foaming process does not break the current but only passes through the electrolytic copper foil in the plating bath, Current flows to make fine nodules. At this time, it is possible to make fine nodules at the same time on both the mat and the shiny surface by applying an electric current to the electrode in the plating tank for treating the shiny not only the matt surface but also the shiny surface. That is, in terms of productivity, it is possible to easily manufacture the secondary battery and the flexible copper-clad laminated film even if the current is applied for any purpose. In the case of the secondary battery, the second sub-barrier treatment is performed after the fine nodule treatment, thereby imparting rustproofing.

Hereinafter, the flexible copper clad laminated film (FCCL) of the present invention will be described in detail with reference to FIG.

6, the flexible copper-clad laminate film of the present invention includes an electrolytic copper foil 100 having a matte surface and a shiny surface opposite thereto, and a non-conductive polymer film 200 on the mat surface of the electrolytic copper foil 100. [

As described above, the electrolytic copper foil 100 has a plurality of nodules N disposed on the mat surface and a plurality of nodules N disposed on the surface of at least one of the nodules N, And includes fine nodes MN. The R _z of the matte surface may be 0.8 to 3 탆.

According to an embodiment of the present invention, the thickness of the electrolytic copper foil 100 may be 1 to 70 탆.

6, the electrolytic copper foil 100 includes a main copper layer 110, a copper layer 120 on the main copper layer 110, a fine metal layer 130 on the copper layer 120, And a barrier layer 140 on the fine nodule layer 130.

The barrier layer 140 may include a first sub-barrier layer 141 on the micro-nodule layer 130 and a second sub-barrier layer 142 on the first sub-barrier layer 141. The first sub-barrier layer 141 is for imparting oxidation resistance, heat resistance and chemical resistance to the electrolytic copper foil 100 and is made of zinc (Zn), zinc alloy, nickel (Ni), iron (Fe), cobalt ), Vanadium (V), and molybdenum (Mo), preferably 3 to 20 mg / m ² of zinc (Zn) or zinc alloy. The second sub-barrier layer 142 is for preventing corrosion when the electrolytic copper foil 100 of the present invention is stored for a long period of several months, and may include chromium (Cr). The surface of the second sub-barrier layer 142 in contact with the nonconductive polymer membrane 200 may be modified with a silane coupling agent.

According to a preferred embodiment of the present invention, the nonconductive polymer membrane 200 may include polyimide and may be formed by laminating a polyimide film on the electrolytic copper foil 100 through a roll press, The precursor solution may be coated on the electrolytic copper foil 100 by, for example, a knife coating method, and then heat-treated.

Hereinafter, the present invention will be described in detail with reference to examples and comparative examples. It is to be understood, however, that the present invention is not limited to the following embodiments, but the scope of the present invention is not limited to these embodiments.

Example 1

A positive electrode plate and a rotating negative electrode drum, which were arranged so as to be spaced apart from each other by a distance of 10 mm in the electrolytic solution (main component: copper sulfate, additive: gelatin, HEC, SPS) contained in the electrolytic cell, were electrodeposited with a current density of 50 ASD, (electrodeposit), and as a result, the main copper film was formed.

Subsequently, a plurality of nodules were formed on the main copper film by sequentially passing the main copper film through the first and second copper plating baths.

The first copper plating bath contained a first plating solution for the powdering process. The first plating solution was maintained at 25 캜 and contained 20 g / L of copper ion, 150 g / L of sulfuric acid, and 300 ppm of molybdenum (Mo) as an additive. The current density applied for the powdering process was 30 ASD.

The second copper plating bath contained a second plating solution for the encapsulation process. The second plating solution contained 40 g / L of copper ion and 100 g / L of sulfuric acid and was maintained at 40 캜. The current density applied for the encapsulation process was 10 ASD.

Subsequently, the main copper film on which the nodules were formed passed through a third plating solution in the third copper plating bath to form a plurality of fine nodules on the surface of the nodules. The third plating solution contained 8 g / L of copper ion, 15 g / L of nickel ion, and 150 g / L of sulfuric acid and was maintained at 25 캜. The current density applied for fine nodule formation was 5 ASD.

Subsequently, the main copper film on which the fine nodules were formed was sequentially passed through a zinc plating bath for forming the first sub-barrier layer and a chromium plating bath for forming the second sub-barrier layer to complete an electrolytic copper foil having a thickness of 18 μm.

Example 2

An electrolytic copper foil was prepared in the same manner as in Example 1, except that the applied current density for forming fine nodules was 10 ASD.

Example 3

An electrolytic copper foil was prepared in the same manner as in Example 1 except that the applied current density for forming fine nodules was 15 ASD.

Example 4

An electrolytic copper foil was prepared in the same manner as in Example 1, except that the applied current density for forming fine nodules was 20 ASD.

Comparative Example 1

An electrolytic copper foil was prepared in the same manner as in Example 1 except that the fine nodule formation process was omitted.

Comparative Example 2

An electrolytic copper foil was prepared in the same manner as in Example 1 except that the applied current density for forming fine nodules was 3 ASD.

Comparative Example 3

An electrolytic copper foil was prepared in the same manner as in Example 1, except that the applied current density for forming fine nodules was 25 ASD.

(Ii) the surface roughness (R _z ), (iii) the peel strength to the polyimide film, (iv) the presence or absence of residuals, and And (v) capacity retention of a secondary battery including a negative electrode made of electrolytic copper foils of Examples and Comparative Examples were measured by the following methods, and the results are shown in Table 1.

* Presence of fine nodule and its longest diameter

The matt surface of the electrolytic copper foil was observed at a magnification of 20,000 × after tilting it at 45 ° with a scanning electron microscope to check the existence of fine nodules and measure the longest diameter thereof.

* Surface roughness (R _z )

The R _z of the mat surface of the electrolytic copper foil was measured using a contact type surface roughness meter (SJ-210 manufactured by Mitsudo Co., Ltd.) according to JIS B 0601-1994.

* Peel strength and residuals

A polyamic acid solution was coated on the matte side of the electrolytic copper foil, followed by imidization through thermosetting, thereby producing a laminate sample of an electrolytic copper foil and a polyimide film. The peel strength between the electrolytic copper foil and the polyimide film was measured according to JIS C 6481 standard. Subsequently, whether or not the nodule remained on the surface of the polyimide film after the peeling strength measurement was observed by an optical microscope was checked to determine whether the residue was present.

* Capacity retention rate of secondary battery (%)

First, negative electrodes were prepared from the electrolytic copper foils of Examples 1-4 and Comparative Examples 1-3. Specifically, 2 parts by weight of SBR (styrene butadiene rubber) and 2 parts by weight of CMC (caroboxymethylcellulose) were mixed with 100 parts by weight of carbon commercially available as an anode active material. Then, a slurry was prepared by adding distilled water as a solvent to this mixture. The slurry was coated on the surface of an electrolytic copper foil (width: 10 cm) to a thickness of about 60 μm using a doctor blade, dried at 120 ° C., and then subjected to a roll pressing process (pressure: 1 ton / cm ² ) to prepare a negative electrode.

Lithium manganese oxide _{(Li 1. 1 Mn 1.} 85 Al 0. 05 O 4) and lithium manganese oxide (LiMnO _2-o) in the orthorhombic crystal structure was prepared the positive electrode active material were mixed at a weight ratio of 90:10. The above cathode active material, carbon black, and polyvinylidene fluoride (PVDF) were mixed with NMP as an organic solvent at a weight ratio of 85: 10: 5 to prepare a slurry. The slurry was coated on both sides of an aluminum foil having a thickness of 20 mu m and dried to prepare a positive electrode.

Further, 1 M of LiPF ₆ dissolved as a solute in a non-aqueous organic solvent in which ethylene carbonate (EC) and ethyl methyl carbonate (EMC) were mixed at a weight ratio of 1: 2 was used as a basic electrolyte, and 99.5% by weight of this basic electrolyte, And 0.5 wt% of succinic anhydride were mixed to prepare an electrolytic solution.

A secondary battery was prepared from the thus prepared negative electrode, positive electrode, and electrolyte.

Then, the capacity per g of the positive electrode was measured with the charging operating voltage of 4.3 V and the discharging operating voltage of 3.4 V, and the charging / discharging time of 50 cycles at a charging / discharging rate of 0.2 C at 50 캜 And the capacity retention rate of the secondary battery was calculated according to the following equation (1). (For reference, the capacity retention rate after 50 charge / discharge cycles of a secondary battery required in the industry is more than 90%.)

[Formula 1]

Capacity retention rate (%) = (capacity after 50 times charge / discharge / capacity after 1 charge / discharge) × 100

Whether to perform the fine nodule formation process Fine Nodule
Upon formation,
Current density (ASD) Fine Nodule
existence
Whether maximum
Longest diameter of fine nodule
(탆) R _z
(탆) Peel strength
(kgf / cm) Persistence
The presence or absence Volume
Retention rate
(%) Example 1 ○ 5 ○ 0.11 2.65 0.80 × 91 Example 2 ○ 10 ○ 0.14 2.66 0.79 × 91 Example 3 ○ 15 ○ 0.16 2.68 0.81 × 93 Example 4 ○ 20 ○ 0.18 2.69 0.82 × 92 Comparative Example 1 × - × - 2.60 0.50 × 82 Comparative Example 2 ○ 3 × - 2.61 0.51 × 85 Comparative Example 3 ○ 25 ○ 0.25 3.10 0.82 ○ 91

As can be seen from the above Table 1, the electrolytic copper foils of Example 1-4 in which the fine nodules were formed showed only a small increase in surface roughness (R _z ) compared to the case where the fine nodule formation process was not performed (Comparative Example 1) It was found that the peeling strength of the polyimide film was significantly improved. On the other hand, in the case of Comparative Example 2, in which the current density applied in the micro nodule formation process was less than 5 ASD, no micro nodules were formed, The strength increase was hardly observed.

On the other hand, in the case of Comparative Example 3 in which the current density was less than 25 ASD in the micro nodule formation process, micro nodules were excessively grown and micro nodules having a maximum diameter exceeding 0.2 m were observed, and the surface roughness (R _z ) Has reached a level that can not be applied to a thin nonconductive polymer membrane for a small electronic device. In the case of Comparative Example 3, after the peeling strength test, the residual was observed, which causes short circuit of the flexible printed circuit board (FPCB) as described above.

On the other hand, the lithium secondary batteries manufactured from the electrolytic copper foils of Examples 1-4 and Comparative Example 3 in which the fine nodules were formed showed excellent capacity retention ratios of 90% or more after 50 cycles of charging and discharging, while Comparative Examples 1 and 2 2 lithium secondary batteries showed a low capacity retention ratio of less than 90% after 50 cycles of charging and discharging. Accordingly, it can be seen that the fine nodule improves the adhesion between the electrolytic copper foil and the negative electrode active material, thereby suppressing the desorption of the active material during charging and discharging of the secondary battery.

7 is a graph of surface roughness (R _z ) of an electrolytic copper foil with respect to a current density applied during a process of forming a fine nodular layer, obtained from Example 1-4 and Comparative Example 2-3. 7, it can be seen that the surface roughness (R _z ) of the electrolytic copper foil sharply increases when the current density applied in the micro nodule formation process exceeds 20 ASD.

100: electrolytic copper foil 110: main copper film
120: copper nodule layer 130: fine nodule layer
140: barrier layer 200: nonconductive polymer membrane

Claims (21)

An electrolytic copper foil having a matte surface and a shiny surface opposite to the matte surface,
A plurality of nodules disposed on the matte surface; And
A plurality of micro-nodes located on a surface of at least one of the nodules and having a maximum diameter of 0.2 탆 or less, wherein the maximum diameter means a maximum diameter in a direction parallel to the shiny surface Features,
An electric boat. The method according to claim 1,
Characterized in that the fine nodules comprise at least one of Cu, Ni, Zn, Fe, Cr, and Mo.
An electric boat. The method according to claim 1,
Characterized in that R _z of the mat surface is 0.8 to 3 탆.
An electric boat. The method according to claim 1,
Characterized in that the fine nodules have a spherical shape or a needle shape.
An electric boat. The method according to claim 1,
Wherein the thickness of the electrolytic copper foil is 1 to 70 mu m.
An electric boat. The method according to claim 1,
The electrolytic copper foil,
A main copper film;
A copper nodule layer on the main copper layer, the copper nodule layer including the nodules;
A micro-nodule layer on the copper node layer, the micro node layer comprising the micro nodes; And
And a barrier layer on the fine nodule layer.
An electric boat. The method according to claim 6,
Wherein the barrier layer comprises:
A first sub-barrier layer on the fine nodal layer; And
And a second sub-barrier layer on the first sub-barrier layer.
An electric boat. 8. The method of claim 7,
Wherein the first sub-barrier layer comprises zinc or a zinc alloy,
Wherein the second sub-barrier layer comprises chromium,
An electric boat. 9. The method of claim 8,
Wherein the surface of the second sub-barrier layer is modified with a silane coupling agent.
An electric boat. Forming a main copper film through electrolytic plating;
Forming a copper layer on the main copper layer; And
Forming a fine nodular layer on the copper nodule layer including a plurality of fine nodules having a maximum diameter of 0.2 탆 or less, wherein the longest diameter means a maximum diameter in a direction parallel to the shiny side ≪ / RTI >
Method of manufacturing electrolytic copper foil. 11. The method of claim 10,
In the copper seed layer formation step,
Performing a powdering process to produce nodule nuclei on the main copper film; And
And performing a capsuling process to stabilize the nodule nuclei.
Method of manufacturing electrolytic copper foil. 12. The method of claim 11,
The powdering process is performed at a current density of 20 to 50 ASD in a first plating solution maintained at 20 to 30 DEG C,
Wherein the first plating solution comprises 15 to 35 g / L of copper ions, 90 to 210 g / L of sulfuric acid, 0.01 to 5 g / L of an additive,
Wherein the additive is at least one of Ti, V, Cr, Fe, Co, Mo, W, and Ni, or a mixture of two or more thereof.
Method of manufacturing electrolytic copper foil. 13. The method of claim 12,
The encapsulation process is performed at a current density of 5 to 40 ASD in a second plating solution maintained at 40 to 60 DEG C,
Characterized in that said second plating liquid comprises 40 to 60 g / l of copper ions and 90 to 210 g / l of sulfuric acid.
Method of manufacturing electrolytic copper foil. 14. The method of claim 13,
Characterized in that the powdering step and the encapsulating step are alternately performed at least twice each,
Method of manufacturing electrolytic copper foil. 11. The method of claim 10,
The microdomule layer forming step is performed at a current density of 5 to 20 ASD in a third plating solution maintained at 20 to 30 DEG C,
Wherein the third plating solution comprises 7 to 10 g / L of copper ions, 14 to 16 g / L of nickel ions, and 90 to 210 g / L of sulfuric acid.
Method of manufacturing electrolytic copper foil. 11. The method of claim 10,
Further comprising the step of forming a barrier layer on the fine nodule layer.
Method of manufacturing electrolytic copper foil. 17. The method of claim 16,
The forming of the barrier layer may include:
Forming a first sub-barrier layer comprising zinc or a zinc alloy on the micro-nodular layer; And
And forming a second sub-barrier layer containing chromium on the first sub-barrier layer.
Method of manufacturing electrolytic copper foil. 18. The method of claim 17,
Further comprising modifying the surface of the second sub-barrier layer with a silane coupling agent.
Method of manufacturing electrolytic copper foil. An electrolytic copper foil according to any one of claims 1 to 9, And
And a nonconductive polymer membrane on the mat surface of the electrolytic copper foil.
Flexible copper foil laminated film. An electrolytic copper foil according to any one of claims 1 to 9, And
And a negative electrode active material layer on the mat surface of the electrolytic copper foil,
cathode. anode;
A cathode according to claim 20;
An electrolyte for providing an environment in which lithium ions can move between the anode and the cathode; And
And a separator for electrically insulating the anode and the cathode.
Secondary battery.

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