KR102048116B1 - High-strength, low-warping electrolytic copper foil and method for producing same - Google Patents

Abstract

The tensile strength in the state (hereinafter referred to as "state tensile strength") is 45 kgf / mm 2 to 55 kgf / mm 2, and the average value of the lift amount of four corners having a width of 100 mm is 2 mm or less. The said electrolytic copper foil which is 85% or more of the state tensile strength value is the tensile strength (henceforth "heating tensile strength after heating") after heating at 180 degreeC for 60 minute and electrolytic copper foil to be used. It is an object of the present invention to provide an electrolytic copper foil useful for an electrolytic copper foil having high state tensile strength and heating tensile strength and low warpage, in particular, a negative electrode current collector for a secondary battery.

Description

High strength and low warpage electrolytic copper foil and its manufacturing method {HIGH-STRENGTH, LOW-WARPING ELECTROLYTIC COPPER FOIL AND METHOD FOR PRODUCING SAME}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrolytic copper foil having high strength and low warpage and a method for producing the same, and particularly to an electrolytic copper foil useful for a secondary battery negative electrode current collector.

Electrolytic copper foil manufactured by electroplating contributes greatly to the development of an electric and electronic related industry, and has become an indispensable presence as a printed circuit material and a secondary battery negative electrode collector. Although the history of manufacture of an electrolytic copper foil is long (refer patent document 1 and patent document 2), the usefulness is reconfirmed as a secondary battery negative electrode electrical power collector recently.

When manufacturing example of an electrolytic copper foil is shown, the electrode is arrange | positioned, for example by the titanium or stainless steel rotating drum which is about 3000 mm in diameter and about 2500 mm in width, and the clearance gap about 5 mm around the drum. do.

Copper, sulfuric acid, and glue are introduced into this electrolytic cell to obtain an electrolytic solution. Then, the flux, the electrolyte temperature, and the current density are adjusted to deposit copper on the surface of the rotating drum, and the copper deposited on the surface of the rotating drum is peeled off to continuously manufacture copper foil.

This electrolytic copper foil manufacturing method can aim at reduction of manufacturing cost, can manufacture from the very thin layer thickness of several micrometers to the thick copper foil of 70 micrometers, and since the single side | surface of an electrolytic copper foil has moderate roughness, This has many advantages that the adhesive strength with the resin is high.

In recent years, although electrolytic copper foil is used as a copper foil for vehicle negative electrode materials for vehicles, it is required that the intensity | strength of an electrolytic copper foil is high as the characteristic. Although the electrolytic copper foil manufactured conventionally has the characteristic which can respond to this heat resistance request | requirement, when the copper foil is taken out from a roll, there exists a problem that a foil is bent.

This is considered to have a cause to the structure which arises in the manufacturing process of an electrolytic copper foil. In the process of manufacturing a battery negative electrode material using an electrolytic copper foil, since the curvature of this electrolytic copper foil is unpreferable, it is necessary to reduce it as much as possible or to prevent it from generating at all. Here, as an evaluation method of the amount of warpage, the electrolytic copper foil was punched into a 100 mm long sheet by a press and defined as an average value of the lifted amount of four corners when left at room temperature for 30 minutes, and the subsequent examination was carried out. It shall be said.

Japanese Laid-Open Patent Publication No. 7-188969 Japanese Unexamined Patent Publication No. 2004-107786

TECHNICAL FIELD The present invention relates to an electrolytic copper foil having high strength and low warpage and a method for producing the same, and particularly, to provide an electrolytic copper foil useful for a secondary battery negative electrode current collector.

The present application provides the following invention.

(1) Tensile strength (hereinafter, referred to as "state tensile strength") in the state (i) is 45 kgf / mm 2 to 55 kgf / mm 2, and the average value of the lifted amounts of four corners having a width of 100 mm. It is 2 mm or less, The electrolytic copper foil characterized by the above-mentioned.

(2) The electrolytic copper foil as described in said (1) characterized by the crystal grain of electrolytic copper foil cross section consisting of the fine particle whose aspect ratio is less than 2.0, and the columnar particle whose aspect ratio is 2.0 or more.

(3) The sum total of the area of a columnar particle is 5%-30%, and remainder is a fine particle, The electrolytic copper foil as described in said (1) or (2) characterized by the above-mentioned.

In addition, the present application provides the following invention.

(4) The average particle diameter of the fine particle whose aspect ratio is less than 2.0 is 0.2 micrometer or less, The electrolytic copper foil in any one of said (1)-(3) characterized by the above-mentioned.

(5) It is copper foil for secondary battery negative electrode electrical power collectors, The electrolytic copper foil in any one of said (1)-(4) characterized by the above-mentioned.

(6) A method for producing an electrolytic copper foil by an electrolytic method using a sulfuric acid-based copper electrolytic solution, wherein the electrolytic solution temperature is set to 60 to 65 ° C and the current density is set to 60 to 120 A / dm 2 to be electrolytically characterized. The manufacturing method of an electrolytic copper foil.

(7) In the method for producing an electrolytic copper foil by an electrolytic method using a sulfuric acid-based copper electrolyte, the electrolytic solution temperature is set to 60 to 65 ° C, the current density is set to 60 to 120 A / dm 2, and the electrolysis is performed. )-The manufacturing method of the electrolytic copper foil characterized by manufacturing the electrolytic copper foil in any one of (6).

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrolytic copper foil having high strength and low warpage and a method for producing the same, and particularly, having an excellent effect of providing an electrolytic copper foil useful for a secondary battery negative electrode current collector.

1 is a micrograph showing the shape of particles in the cross section of the electrolytic copper foil of Example 1. FIG.
2 is a micrograph showing the shape of particles in the cross section of the electrolytic copper foil of Comparative Example 1. FIG.

The present invention provides an electrolytic copper foil capable of maintaining the strength without causing warpage by allowing the columnar particles and the fine particles to simultaneously exist in the electrolytic copper foil. The electrolytic copper foil of this invention is especially useful as copper foil for secondary battery negative electrode electrical power collectors.

Specifically, the presence of the columnar particles can reduce the amount of warpage, and the presence of the fine particles can maintain the strength.

That is, the average value of the lifting amount of the four corners which are 100 mm in width and width shall be 45 kgf / mm <2> -55 kgf / mm <2> in tensile strength (henceforth "state tensile strength") in the state of an electrolytic copper foil by this. Can be 2 mm or less.

The higher the current density, the smaller the particles can be formed, and the higher the strength can be. However, even if it is low, it does not fall below the lower limit of this invention. Rather, the problem of bending is large. That is, when the current density is less than 60 A / dm 2, there is no temperature condition that can cause the warpage to be 2 mm or less. This is thought to be because the whole particle | grain becomes large and an effect becomes small even if a columnar particle exists.

On the other hand, when the current density exceeds 120 A / dm 2, the whole becomes too fine, and even if the liquid temperature is increased, it is considered that the columnar particles are less likely to occur and the warpage is increased.

As mentioned above, it turns out that the combination of electrolyte temperature and current density is important for an appropriate range. It can be said that the liquid temperature is lower when the current density is low in the range of an appropriate current density. In addition, when the current density is low, since the original particles tend to be large, when the liquid temperature is increased, the total particle size is larger than the increase in the columnar particles, so that the warpage increases even if there are columnar particles.

On the other hand, it is more preferable that liquid temperature is high when current density is high in the range of a suitable current density. If the current density is high, the particle diameter is originally small, and it is considered that the columnar particles are unlikely to develop unless the liquid temperature is high.

About the particle shape in the structure of an electrolytic copper foil, it can know by observing the cross section of an electrolytic copper foil. For fine particles, the aspect ratio (ratio of the maximum height and the minimum width of the particles) can be less than 2.0, and for the columnar particles, the aspect ratio can be set to 2.0 or more, and the two can be distinguished. The particle shape in the structure of the electrolytic copper foil of this invention is discriminated by this aspect ratio.

In this invention, the sum total of the area of a columnar particle may be 10%-55%, and remainder can be made into fine particle. The "area of columnar particle" means the "area of columnar particle" which can be observed in the cross section of an electrolytic copper foil here. This is a preferable aspect which can suppress the curvature of an electrolytic copper foil and can maintain strength.

When there are too few columnar particles, ie, less than 5%, curvature becomes large, and it is unpreferable. Moreover, when it exceeds 30%, since a fine particle becomes comparatively small on the contrary, intensity | strength falls and it is not preferable. Therefore, it can be said that it is a preferable condition to make the sum total of the area of a columnar particle into 5%-30%.

Moreover, in this invention, it is preferable that the average particle diameter of the fine particle which exists in an electrolytic copper foil, ie, the fine particle whose aspect ratio is less than 2.0, is 0.2 micrometer or less. The fine particles play a role of increasing strength as described above, and the lower limit of the average particle diameter is not particularly limited. When the average particle diameter of this fine particle becomes large, even if columnar particle exists, there exists a tendency for the effect of the columnar particle | grains of reduction of curvature to reduce. Therefore, it is a preferable aspect that the average particle diameter of a fine particle is 0.2 micrometer or less. Moreover, about the thickness of the copper foil for secondary battery negative electrode collectors, 20 micrometers or less are preferable and 10 micrometers or less are more preferable.

The electrolytic copper foil of this invention manufactures an electrolytic copper foil by the electrolytic method using a sulfate type copper electrolyte solution. The present invention relates to a titanium or stainless steel rotary drum having a diameter of about 3000 mm and a width of about 2500 mm, and a conventional electrolytic copper foil manufacturing apparatus in which electrodes are arranged at intervals of about 5 mm around the drum. Can be prepared. An example of this apparatus is an example, and the specification of the apparatus is not particularly limited.

Copper concentration: 80-110 g / l, sulfuric acid concentration: 70-110 g / l, glue concentration: 2.0-10.0 ppm are introduce | transduced in this electrolytic cell, and it is set as electrolyte solution.

Then, the flux was adjusted to 3.0 to 5.0 m / s, electrolyte temperature: 60 ° C to 65 ° C, and current density: 60 to 120 A / dm 2 to precipitate copper on the surface of the rotating drum, and to precipitate on the surface of the rotating drum. The copper stripped off is removed, and copper foil is continuously manufactured.

That is, as above-mentioned, electrolytic solution temperature is 60-65 degreeC and current density is 60-120 A / dm <2>, and electrolysis is a preferable condition to obtain the electrolytic copper foil which has the said characteristic. In particular, adjustment of electrolyte temperature is important. Details are described in Examples and Comparative Examples.

On the surface or the back surface of this electrolysis, and also both surfaces, a roughening process can be performed as needed. For example, average surface roughness Ra can be 0.04-0.20 micrometer. In this case, the reason for making the lower limit of average surface roughness Ra into 0.04 micrometer is for forming fine particle | grains and making adhesiveness favorable.

Thereby, for example, it becomes possible to apply | coat as many active materials of a secondary battery as possible, and can raise the electric capacity of a battery. On the other hand, the upper limit is made 0.20 micrometer in order to reduce the variation of weight thickness. Thereby, the charge / discharge characteristic of a secondary battery can be improved, for example. These surface roughness shows an example and can be adjusted suitably according to the use of an electrolytic copper foil.

Moreover, it is preferable to make the average diameter of the roughening particle | grains of a roughening process surface into 0.1-0.4 micrometer, taking the copper foil for negative electrode collectors for secondary batteries as an example. While the roughened particles are fine particles, the fine particles are desired to be more uniform. This is also a preferable form in order to improve the adhesiveness of a battery active material, to apply | coat as many active materials as possible, and to raise the electric capacity of a battery.

Moreover, it is preferable that the maximum height of the roughening process layer sets the copper foil for negative electrode electrical power collectors for secondary batteries to 0.2 micrometer or less. This is also a preferable form in order to reduce the thickness variation of a roughening process layer, to improve the adhesiveness of a battery active material, to apply as many active materials as possible, and to raise the electric capacity of a battery.

This invention can manage this based on the parameter | index which makes thickness of this roughening particle into 0.2 micrometer or less, and can achieve this.

The copper foil for negative electrode collectors for secondary batteries can form 1 type of plating of copper, cobalt, nickel, or these 2 or more types of alloy plating as a roughening particle. Usually, roughening particle | grains are formed by the triad alloy plating of copper, cobalt, and nickel. In addition, in order to improve heat resistance and weather resistance (corrosion resistance), the copper foil for negative electrode collectors for secondary batteries is a cobalt- nickel-alloy plating layer, a zinc- nickel-alloy plating layer, and a chromate layer on the roughening process surface of both front and back of a rolled copper alloy foil. It is an element of a preferable form to form at least one antirust layer or heat resistant layer and / or silane coupling layer selected from.

By the above, the copper foil for negative electrode collectors for secondary batteries of this invention can make the weight thickness variation of the copper foil width direction of the rolled copper alloy foil after front and back double-side roughening process into 0.5% or less, and is excellent copper foil for negative electrode collectors for secondary batteries Can be provided.

The roughening process on the copper foil for negative electrode collectors for secondary batteries of this invention can perform a roughening process of copper or a copper-cobalt-nickel alloy plating process, for example.

For example, the roughening process of copper is as follows.

Copper conditioning treatment

Cu: 10-25 g / l

H ₂ SO ₄ : 20 to 100 g / l

Temperature: 20-40 degrees Celsius

Dk: 30 to 70 A / dm 2

Time ： 1 to 5 seconds

Moreover, the roughening process by a copper- cobalt- nickel alloy plating process is as follows. The electrolytic plating is carried out so as to form a ternary alloy layer having an adhesion amount of 15 to 40 mg / dm 2 copper-100 to 3000 µg / dm 2 cobalt-100 to 500 µg / dm 2 nickel. This ternary alloy layer is also equipped with heat resistance.

General baths and plating conditions for forming such ternary copper-cobalt-nickel alloy plating are as follows.

(Copper-cobalt-nickel alloy plating)

Cu: 10 to 20 g / l

Co: 1 to 10 g / l

Ni: 1 to 10 g / l

pH ： 1-4

Temperature: 30-50 degrees Celsius

Current density D _k : 20 to 50 A / dm 2

Time: 1 to 5 seconds

After the roughening treatment, a cobalt-nickel alloy plating layer can be formed on the roughened surface. In this cobalt-nickel alloy plating layer, the adhesion amount of cobalt is 200-3000 microgram / dm <2>, and the ratio of cobalt is 60-70 mass%. This process can be regarded as a kind of antirust process in a broad sense.

The conditions of the cobalt-nickel alloy plating are as follows.

(Cobalt-Nickel Alloy Plating)

Co: 1-20 g / l

Ni: 1-20 g / l

pH ： 1.5 to 3.5

Temperature: 30-80 degrees Celsius

Current density D _k : 1.0 to 20.0 A / dm 2

Time: 0.5 to 4 seconds

In addition to the cobalt-nickel alloy plating, a zinc-nickel alloy plating layer may be formed. The total amount of the zinc-nickel alloy plating layer is 150 to 500 µg / dm 2, and the proportion of nickel is 16 to 40 mass%. This has a role of a heat resistant antirust layer.

The conditions of zinc-nickel alloy plating are as follows.

(Zinc-Nickel Alloy Plating)

Zn: 0 to 30 g / l

Ni: 0-25 g / l

pH: 3-4

Temperature: 40-50 degrees Celsius

Current density D _k : 0.5 to 5 A / dm 2

Time: 1-3 seconds

Subsequently, the following rust prevention process can also be performed as needed. Preferred antirust treatment is coating treatment of chromium oxide alone or coating treatment of chromium oxide and zinc / zinc oxide. The coating layer of a mixture of chromium oxide and zinc / zinc oxide is an antirust layer of a zinc-chromium group mixture composed of zinc or zinc oxide and chromium oxide by electroplating using a zinc salt or a plating bath containing zinc oxide and chromate. It is a treatment to coat.

The plating bath include, typically, a K ₂ Cr ₂ O _7, for at least one type and a water-soluble zinc salts, for example, such as dichromate or CrO _3, such as _{Na 2 Cr 2 O 7 ZnO,} ZnSO 4 · 7H 2 O Etc. At least 1 sort (s) and the mixed aqueous solution of alkali hydroxide are used. Representative plating bath compositions and electrolytic conditions are as follows. The copper foil thus obtained has excellent heat resistance peel strength, oxidation resistance and hydrochloric acid resistance.

(Chrome rust prevention treatment)

K ₂ Cr ₂ O ₇ (Na ₂ Cr ₂ O ₇ or CrO ₃ ): 2 to 10 g / l

NaOH or KOH: 10 to 50 g / l

ZnO or ZnSO ₄ · 7H ₂ O: 0.05 to 10 g / l

pH ： 3 to 13

Bath temperature: 20-80 degrees Celsius

Current density D _k : 0.05 to 5 A / dm 2

Time: 5-30 seconds

Anode: Pt-Ti plate, stainless steel sheet

As the amount of chromium oxide, a coating amount of 15 µg / dm 2 or more and zinc of 30 µg / dm 2 or more are required.

Finally, the silane treatment which apply | coats a silane coupling agent on at least roughening surface on a rustproof layer is performed mainly as a main objective of the improvement of the adhesive force of copper foil and a resin substrate as needed. As a silane coupling agent used for this silane treatment, an olefin type silane, an epoxy type silane, an acryl type silane, an amino type silane, a mercapto type silane is mentioned, These can be selected suitably and can be used.

The coating method may be any of spraying with a silane coupling agent solution, coating with a coater, dipping, and shedding. For example, Japanese Patent Application Laid-Open No. 60-15654 describes improving the adhesive force between the copper foil and the resin substrate by performing a chromate treatment on the rough surface side of the copper foil and then performing a silane coupling agent treatment. See this for details. After that, if necessary, annealing treatment may be performed for the purpose of improving the ductility of the copper foil.

About the above, although the additional surface treatment layer with respect to the electrolytic copper foil of this invention mainly applied to the negative electrode electrical power collector for secondary batteries was demonstrated, it cannot be overemphasized that these can be arbitrarily applied according to the use of an electrolytic copper foil. The present invention includes all of these.

Example

Hereinafter, it demonstrates based on an Example and a comparative example. In addition, this embodiment is an example to the last and is not limited only to this example. That is, the other aspect or modification contained in this invention is included.

(Example 1)

In the electrolytic cell, electrodes are arranged at a rotary drum made of titanium having a diameter of about 3133 mm and a width of 2476.5 mm with a gap distance of about 5 mm around the drum. Copper concentration: 90 g / L, sulfuric acid concentration: 80 g / L, glue concentration: 3 ppm were introduced into this electrolytic cell to obtain an electrolyte solution.

Then, the flow rate was adjusted to 3.0 m / s, electrolyte temperature: 60 ° C., current density: 84 A / dm 2, to precipitate copper on the surface of the rotating drum, and the copper deposited on the surface of the rotating drum was peeled off. Copper foil was prepared.

This condition is shown in Table 1. The area ratio of the columnar particles, the size of the fine particles, the strength (state tensile strength), and the amount of warpage of the thus prepared electrolytic copper foil were examined. As a result, the area ratio of the columnar particles was 50%, the size of the fine particles: less than 0.2 µm, the strength (state tensile strength): 51.4 kgf / mm 2, and the amount of warpage: 1.5 mm.

All satisfied the conditions of the present invention. This result is shown in Table 1 similarly. In addition, in Table 1, although the "column particle" is described as "column phase crystal | crystallization", both are the meanings of "particle which consists of columnar crystals", and are used by the same meaning. The same applies to the following.

In addition, in the Example, it is a case where current density is set to 84 A / dm <2>. Moreover, the micrograph which shows the particle shape of this electrolytic copper foil cross section is shown in FIG. In this FIG. 1, the pillar-shaped particle whose aspect ratio is 2.0 or more, and the fine particle whose aspect ratio is less than 2.0 are mixed.

(Example 2)

In the electrolytic cell, electrodes are arranged at a rotary drum made of titanium having a diameter of about 3133 mm and a width of 2476.5 mm with a gap distance of about 5 mm around the drum. Copper concentration: 90 g / L, sulfuric acid concentration: 80 g / L, glue concentration: 3 ppm were introduced into this electrolytic cell to obtain an electrolyte solution.

Then, the flux was adjusted to 3.0 m / s, electrolyte temperature: 63 ° C., current density: 84 A / dm 2, to precipitate copper on the surface of the rotating drum, and to remove copper deposited on the surface of the rotating drum, thereby continuously Copper foil was prepared.

This condition is shown in Table 1. The area ratio of the columnar particles, the size of the fine particles, the strength (state tensile strength), and the amount of warpage of the thus prepared electrolytic copper foil were examined. As a result, the area ratio of the columnar particles was 29%, the size of the fine particles: 0.2 µm, the strength (state tensile strength): 50.7 kgf / mm 2, and the amount of warpage: 1.7 mm.

All satisfied the conditions of the present invention. This result is shown in Table 1 similarly.

(Example 3)

In the electrolytic cell, electrodes are arranged at a rotary drum made of titanium having a diameter of about 3133 mm and a width of 2476.5 mm with a gap distance of about 5 mm around the drum. Copper concentration: 90 g / L, sulfuric acid concentration: 80 g / L, glue concentration: 3 ppm were introduced into this electrolytic cell to obtain an electrolyte solution.

Then, the flow rate was adjusted to 3.0 m / s, the electrolyte temperature was 63 ° C., and the current density was 109 A / dm 2 to precipitate copper on the surface of the rotating drum, and the copper precipitated on the surface of the rotating drum was peeled off and continuously. Copper foil was prepared.

This condition is shown in Table 1. The area ratio of the columnar particles, the size of the fine particles, the strength (state tensile strength), and the amount of warpage of the thus prepared electrolytic copper foil were examined. As a result, the area ratio of the columnar particles: 42%, the size of the fine particles: less than 0.2 µm, the strength (state tensile strength): 51.1 kgf / mm 2, and the amount of warpage: 1.8 mm. All satisfied the conditions of the present invention. This result is shown in Table 1 similarly.

(Example 4)

In the electrolytic cell, electrodes are arranged at a rotary drum made of titanium having a diameter of about 3133 mm and a width of 2476.5 mm with a gap distance of about 5 mm around the drum. Copper concentration: 90 g / L, sulfuric acid concentration: 80 g / L, glue concentration: 3 ppm were introduced into this electrolytic cell to obtain an electrolyte solution.

Then, the flow rate was adjusted to 3.0 m / s, electrolyte temperature: 65 ° C., current density: 84 A / dm 2, to precipitate copper on the surface of the rotating drum, and to strip off the copper deposited on the surface of the rotating drum. Copper foil was prepared.

This condition is shown in Table 1. The area ratio of the columnar particles, the size of the fine particles, the strength (state tensile strength), and the amount of warpage of the thus prepared electrolytic copper foil were examined. As a result, the area ratio of the columnar particles was 23%, the size of the fine particles: 0.2 µm, the strength (state tensile strength): 48.8 kgf / mm 2, and the amount of warpage: 1.4 mm. All satisfied the conditions of the present invention. This result is shown in Table 1 similarly.

(Example 5)

In the electrolytic cell, electrodes are arranged at a rotary drum made of titanium having a diameter of about 3133 mm and a width of 2476.5 mm with a gap distance of about 5 mm around the drum. Copper concentration: 90 g / L, sulfuric acid concentration: 80 g / L, glue concentration: 3 ppm were introduced into this electrolytic cell to obtain an electrolyte solution.

Then, the flow rate was adjusted to 3.0 m / s, electrolyte temperature: 65 ° C., and current density: 97 A / dm 2 to precipitate copper on the surface of the rotating drum, and the copper precipitated on the surface of the rotating drum was peeled off. Copper foil was prepared.

This condition is shown in Table 1. The area ratio of the columnar particles, the size of the fine particles, the strength (state tensile strength), and the amount of warpage of the thus prepared electrolytic copper foil were examined. As a result, the area ratio of the columnar particles was 32%, the size of the fine particles: 0.2 µm, the strength (state tensile strength): 49.2 kgf / mm 2, and the amount of warpage: 1.6 mm. All satisfied the conditions of the present invention. This result is shown in Table 1 similarly.

(Example 6)

In the electrolytic cell, electrodes are arranged at a rotary drum made of titanium having a diameter of about 3133 mm and a width of 2476.5 mm with a gap distance of about 5 mm around the drum. Copper concentration: 90 g / L, sulfuric acid concentration: 80 g / L, glue concentration: 3 ppm were introduced into this electrolytic cell to obtain an electrolyte solution.

Then, the flow rate was adjusted to 3.0 m / s, electrolyte temperature: 65 ° C., and current density: 109 A / dm 2 to precipitate copper on the surface of the rotating drum, and the copper deposited on the surface of the rotating drum was peeled off, thereby continuously. Copper foil was prepared.

This condition is shown in Table 1. The area ratio of the columnar particles, the size of the fine particles, the strength (state tensile strength), and the amount of warpage of the thus prepared electrolytic copper foil were examined. As a result, the area ratio of the columnar particles was 28%, the size of the fine particles: 0.2 µm, the strength (state tensile strength): 49.5 kgf / mm 2, and the amount of warpage: 1.7 mm.

All satisfied the conditions of the present invention. This result is shown in Table 1 similarly.

(Example 7)

In the electrolytic cell, electrodes are arranged at a rotary drum made of titanium having a diameter of about 3133 mm and a width of 2476.5 mm with a gap distance of about 5 mm around the drum. Copper concentration: 90 g / L, sulfuric acid concentration: 80 g / L, glue concentration: 3 ppm were introduced into this electrolytic cell to obtain an electrolyte solution.

Then, the flow rate was adjusted to 3.0 m / s, electrolyte temperature: 65 ° C., and current density: 120 A / dm 2 to precipitate copper on the surface of the rotating drum, and the copper deposited on the surface of the rotating drum was peeled off, thereby continuously. Copper foil was prepared.

This condition is shown in Table 1. The area ratio of the columnar particles, the size of the fine particles, the strength (state tensile strength), and the amount of warpage of the thus prepared electrolytic copper foil were examined. As a result, the area ratio of the columnar particles was 52%, the size of the fine particles: 0.2 µm, the strength (state tensile strength): 51.0 kgf / mm 2, and the amount of warpage: 1.8 mm. All satisfied the conditions of the present invention. This result is shown in Table 1 similarly.

(Comparative Example 1)

In the electrolytic cell, electrodes are arranged at a rotary drum made of titanium having a diameter of about 3133 mm and a width of 2476.5 mm with a gap distance of about 5 mm around the drum. Copper concentration: 90 g / L, sulfuric acid concentration: 80 g / L, glue concentration: 3 ppm were introduced into this electrolytic cell to obtain an electrolyte solution.

Then, the flow rate was adjusted to 3.0 m / s, electrolyte temperature: 57 ° C., current density: 84 A / dm 2, to precipitate copper on the surface of the rotating drum, and the copper precipitated on the surface of the rotating drum was peeled off. Copper foil was prepared.

This condition is shown in Table 1. The area ratio of the columnar particles, the size of the fine particles, the strength (state tensile strength), and the amount of warpage of the thus prepared electrolytic copper foil were examined. As a result, the area ratio of the columnar particles was 6%, the size of the fine particles was less than 0.2 µm, the strength (state tensile strength): 60.6 kgf / mm 2, and the amount of warpage was 7.5 mm. It is a microscope picture which shows the shape of the particle | grains of the cross section of the electrolytic copper foil of the comparative example 1.

In FIG. 1 of Example 1, the columnar particles having an aspect ratio of 2.0 or more and the fine particles having an aspect ratio of less than 2.0 are in a mixed state, whereas in FIG. 2 of Comparative Example 1, the columnar particles having an aspect ratio of 2.0 or more There was little and the undesirable tendency was that most of the fine particles were less than 2.0. That is, the sum total of the area of a columnar particle | grain did not satisfy the requirement of this invention that it is 10% or more. Although this result is shown in Table 1, it became a cause of the curvature increase compared with an Example.

(Comparative Example 2)

In the electrolytic cell, electrodes are arranged at a rotary drum made of titanium having a diameter of about 3133 mm and a width of 2476.5 mm with a gap distance of about 5 mm around the drum. Copper concentration: 90 g / L, sulfuric acid concentration: 80 g / L, glue concentration: 3 ppm were introduced into this electrolytic cell to obtain an electrolyte solution.

Then, the flow rate was adjusted to 3.0 m / s, electrolyte temperature: 57 ° C., current density: 97 A / dm 2, to precipitate copper on the surface of the rotating drum, and the copper precipitated on the surface of the rotating drum was peeled off. Copper foil was prepared.

This condition is shown in Table 1. The area ratio of the columnar particles, the size of the fine particles, the strength (state tensile strength), and the amount of warpage of the thus prepared electrolytic copper foil were examined. As a result, the area ratio of the columnar particles: 0%, the size of the fine particles: less than 0.2 µm, the strength (state tensile strength): 64.4 kgf / mm 2, and the amount of warpage: 6.9 mm. All did not satisfy the conditions of the present invention. This result is shown in Table 1 similarly.

(Comparative Example 3)

In the electrolytic cell, electrodes are arranged at a rotary drum made of titanium having a diameter of about 3133 mm and a width of 2476.5 mm with a gap distance of about 5 mm around the drum. Copper concentration: 90 g / L, sulfuric acid concentration: 80 g / L, glue concentration: 3 ppm were introduced into this electrolytic cell to obtain an electrolyte solution.

Then, the flow rate was adjusted to 3.0 m / s, electrolyte temperature: 57 ° C., current density: 109 A / dm 2, to precipitate copper on the surface of the rotating drum, and to strip off the copper deposited on the surface of the rotating drum. Copper foil was prepared.

This condition is shown in Table 1. The area ratio of the columnar particles, the size of the fine particles, the strength (state tensile strength), and the amount of warpage of the thus prepared electrolytic copper foil were examined. As a result, the area ratio of the columnar particles: 0%, the size of the fine particles: less than 0.2 µm, the strength (state tensile strength): 66.7 kgf / mm 2, the amount of warpage: 8.1 mm. All did not satisfy the conditions of the present invention. This result is shown in Table 1 similarly.

(Comparative Example 4)

In the electrolytic cell, electrodes are arranged at a rotary drum made of titanium having a diameter of about 3133 mm and a width of 2476.5 mm with a gap distance of about 5 mm around the drum. Copper concentration: 90 g / L, sulfuric acid concentration: 80 g / L, glue concentration: 3 ppm were introduced into this electrolytic cell to obtain an electrolyte solution.

Then, the flow rate was adjusted to 3.0 m / s, electrolyte temperature: 60 ° C., current density: 61 A / dm 2, to precipitate copper on the surface of the rotating drum, and to strip off the copper deposited on the surface of the rotating drum. Copper foil was prepared.

This condition is shown in Table 1. The area ratio of the columnar particles, the size of the fine particles, the strength (state tensile strength), and the amount of warpage of the thus prepared electrolytic copper foil were examined. As a result, the area ratio of the columnar particles was 5%, the size of the fine particles: less than 0.2 µm, the strength (state tensile strength): 50.3 kgf / mm 2, and the amount of warpage: 6.2 mm.

All did not satisfy the conditions of the present invention. This result is shown in Table 1 similarly.

(Comparative Example 5)

In the electrolytic cell, electrodes are arranged at a rotary drum made of titanium having a diameter of about 3133 mm and a width of 2476.5 mm with a gap distance of about 5 mm around the drum. Copper concentration: 90 g / L, sulfuric acid concentration: 80 g / L, glue concentration: 3 ppm were introduced into this electrolytic cell to obtain an electrolyte solution.

Then, the flow rate was adjusted to 3.0 m / s, electrolyte temperature: 60 ° C., current density: 109 A / dm 2, to precipitate copper on the surface of the rotating drum, and the copper precipitated on the surface of the rotating drum was peeled off. Copper foil was prepared.

This condition is shown in Table 1. The area ratio of the columnar particles, the size of the fine particles, the strength (state tensile strength), and the amount of warpage of the thus prepared electrolytic copper foil were examined. As a result, the area ratio of the columnar particles was 6%, the size of the fine particles was less than 0.2 µm, the strength (state tensile strength) was 60.4 kgf / mm 2, and the amount of warpage was 6 mm. All did not satisfy the conditions of the present invention. This result is shown in Table 1 similarly.

(Comparative Example 6)

In the electrolytic cell, electrodes are arranged at a rotary drum made of titanium having a diameter of about 3133 mm and a width of 2476.5 mm with a gap distance of about 5 mm around the drum. Copper concentration: 90 g / L, sulfuric acid concentration: 80 g / L, glue concentration: 3 ppm were introduced into this electrolytic cell to obtain an electrolyte solution.

Then, the flow rate was adjusted to 3.0 m / s, the electrolyte temperature was 63 ° C., and the current density was 61 A / dm 2 to precipitate copper on the surface of the rotating drum, and the copper deposited on the surface of the rotating drum was peeled off and continuously. Copper foil was prepared.

This condition is shown in Table 1. The area ratio of the columnar particles, the size of the fine particles, the strength (state tensile strength), and the amount of warpage of the thus prepared electrolytic copper foil were examined. As a result, the area ratio of the columnar particles was 9%, the size of the fine particles: 0.2 µm, the strength (state tensile strength): 55.3 kgf / mm 2, and the amount of warpage: 12.6 mm. All did not satisfy the conditions of the present invention. This result is shown in Table 1 similarly.

(Comparative Example 7)

In the electrolytic cell, electrodes are arranged at a rotary drum made of titanium having a diameter of about 3133 mm and a width of 2476.5 mm with a gap distance of about 5 mm around the drum. Copper concentration: 90 g / L, sulfuric acid concentration: 80 g / L, glue concentration: 3 ppm were introduced into this electrolytic cell to obtain an electrolyte solution.

Then, the flux was adjusted to 3.0 m / s, electrolyte temperature: 70 ° C., current density: 109 A / dm 2, to precipitate copper on the surface of the rotating drum, and to strip off the copper deposited on the surface of the rotating drum. Copper foil was prepared.

This condition is shown in Table 1. The area ratio of the columnar particles, the size of the fine particles, the strength (state tensile strength), and the amount of warpage of the thus prepared electrolytic copper foil were examined. As a result, the area ratio of the columnar particles was 83%, the size of the fine particles: 0.5 µm, the strength (state tensile strength): 43.0 kgf / mm 2, and the amount of warpage: 0.5 mm. All did not satisfy the conditions of the present invention. This result is shown in Table 1 similarly.

Industrial availability

Since the present invention can provide an electrolytic copper foil having high state tensile strength and heating tensile strength and low warpage, it is particularly useful for an electrolytic copper foil for a negative electrode current collector for a secondary battery.

Claims (25)

Tensile strength in the state (hereinafter referred to as "state tensile strength") is 45 kgf / mm <2> -55 kgf / mm <2>, and the average value of the lifting amount of the four corners of 100 mm width is 2 mm or less,
The crystal grain of an electrolytic copper foil cross section consists of the fine particle whose aspect ratio is less than 2.0, and the columnar particle whose aspect ratio is 2.0 or more,
In the cross section of an electrolytic copper foil, the sum total of the area of the said columnar particle | grains is 10%-55%, and remainder is the said fine particle, The electrolytic copper foil characterized by the above-mentioned. The crystal grain of an electrolytic copper foil cross section consists of the fine particle whose aspect ratio is less than 2.0, and the columnar particle whose aspect ratio is 2.0 or more,
In the cross section of an electrolytic copper foil, the sum total of the area of a columnar particle | grain is 10%-55%, and remainder is a fine particle, The electrolytic copper foil characterized by the above-mentioned. Electrolytic copper foil WHEREIN: The cross section of the said electrolytic copper foil is 10%-55% of the sum total of the area of a columnar particle | grain, and remainder is a fine particle, The electrolytic copper foil characterized by the above-mentioned. The method of claim 1,
The average particle diameter of the said fine particle is 0.2 micrometer or less, The electrolytic copper foil characterized by the above-mentioned. The method of claim 2,
The average particle diameter of the said fine particle is 0.2 micrometer or less, The electrolytic copper foil characterized by the above-mentioned. The method of claim 3, wherein
The average particle diameter of the said fine particle is 0.2 micrometer or less, The electrolytic copper foil characterized by the above-mentioned. The method according to any one of claims 1 to 6,
It is a copper foil for secondary battery negative electrode electrical power collectors, The electrolytic copper foil characterized by the above-mentioned. The method according to any one of claims 1 to 6,
The surface or back surface or both surfaces of an electrolytic copper foil are equipped with the roughening process surface, and the average diameter of the roughening particle | grains of the said roughening process surface is 0.1-0.4 micrometers, The electrolytic copper foil characterized by the above-mentioned. Claim 1 to The method of claim 6, wherein
The surface or back surface or both surfaces of an electrolytic copper foil are equipped with the roughening process surface, and the thickness of the roughening particle of the said roughening process surface is 0.2 micrometer or less, The electrolytic copper foil characterized by the above-mentioned. The method according to any one of claims 1 to 6,
The surface or back surface or both surfaces of an electrolytic copper foil are equipped with the roughening process surface whose average surface roughness Ra is 0.04-0.20 micrometer, The electrolytic copper foil characterized by the above-mentioned. The method of claim 7, wherein
The surface or back surface or both surfaces of an electrolytic copper foil are equipped with the roughening process surface whose average surface roughness Ra is 0.04-0.20 micrometer, The electrolytic copper foil characterized by the above-mentioned. The method of claim 8,
The surface or back surface or both surfaces of an electrolytic copper foil are equipped with the roughening process surface whose average surface roughness Ra is 0.04-0.20 micrometer, The electrolytic copper foil characterized by the above-mentioned. The method of claim 9,
The surface or back surface or both surfaces of an electrolytic copper foil are equipped with the roughening process surface whose average surface roughness Ra is 0.04-0.20 micrometer, The electrolytic copper foil characterized by the above-mentioned. The secondary battery negative electrode current collector using the electrolytic copper foil as described in any one of Claims 1-6. The secondary battery negative electrode using the electrolytic copper foil as described in any one of Claims 1-6. The secondary battery using the negative electrode of Claim 15. In the method of manufacturing an electrolytic copper foil by the electrolytic method using a sulfate type copper electrolyte solution, electrolyte temperature is 60-65 degreeC, line speed is 3.0-5.0 m / s, and current density is 60-120 A / dm <2>. The electrolytic copper foil as described in any one of Claims 1-6 is manufactured by electrolysis as above, The manufacturing method of the electrolytic copper foil characterized by the above-mentioned. The method of claim 17,
Copper concentration: 80-110 g / L, sulfuric acid concentration: 70-110 g / L, glue concentration: 2.0-10.0 ppm are introduce | transduced in an electrolytic cell, and the manufacturing method of the electrolytic copper foil characterized by the above-mentioned. delete delete delete delete delete delete delete

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