# US 2014/0193660 A1 · Electrolytic copper foil and method for producing the same

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- Number: US 2014/0193660 A1
- Document ID: US20140193660A1
- Status: Published application
- Kind: A1
- Application number: 14/063,088
- Filed: 2013-10-25
- Published: 2014-07-10
- Earliest claimed: 2013-01-07
- Assignees: Chang Chun Petrochemical Co., Ltd.
- Applicants: Chang Chun Petrochemical Co., Ltd.
- Inventors: Chen-Ping Tsai; Kuei-Sen Cheng; Chyen-Fu Lin
- Web page: https://patentgrep.com/patent/US20140193660A1

## CPC

- C25D 1/04: Wires; Strips; Foils
- C25D 3/38: of copper
- Y10T 428/12431: Foil or filament smaller than 6 mils
- C25D: PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

An electrolytic copper foil is provided. The electrolytic copper foil has a shiny side and a matte side opposing to the shiny side, wherein the difference in roughness between the shiny side and the matte side is 0.5 μm or less. The electrolytic copper foil has a tensile strength of 45 kg/mm2 or above, and is particularly suitable for applications in a lithium ion secondary battery.

## Claims

### Claim 1

An electrolytic copper foil, comprising:
a shiny side; and
a matte side opposing to the shiny side,
wherein the shiny side and the matte side have a difference in roughness of 0.5 μm or less, and the electrolytic copper foil has a tensile strength of 45 kg/mm2 or above.

### Claim 2 (depends on 1)

The electrolytic copper foil of claim 1, wherein the electrolytic copper foil has an elongation rate of 12% or above after a heat treatment is performed on the electrolytic copper foil at 140° C. for 5 hours.

### Claim 3 (depends on 1)

The electrolytic copper foil of claim 1, wherein the shiny side of the electrolytic copper foil has roughness of 1.6 μm or less.

### Claim 4 (depends on 1)

The electrolytic copper foil of claim 1, wherein the matte side of the electrolytic copper foil has roughness of 1.6 μm or less.

### Claim 5 (depends on 1)

The electrolytic copper foil of claim 1, wherein the matte side of the electrolytic copper foil has gloss of 60 or above at a light incident angle of 60°.

### Claim 6

A method for producing an electrolytic copper foil, comprising steps of:
adding a hydrogen peroxide solution in a copper sulfate electrolyte; and
performing an electrochemical reaction on the copper sulfate electrolyte added with the hydrogen peroxide solution, so as to obtain the electrolytic copper foil.

### Claim 7 (depends on 6)

The method of claim 6, wherein the copper sulfate electrolyte is prepared by dissolving a copper raw material in sulfuric acid.

### Claim 8 (depends on 7)

The method of claim 7, wherein the copper raw material is a copper waste.

### Claim 9 (depends on 6)

The method of claim 6, wherein 6 to 30 mL of the hydrogen peroxide solution is added per ton of the copper sulfate electrolyte per hour.

### Claim 10 (depends on 9)

The method of claim 9, wherein the hydrogen peroxide solution has a concentration of 50 wt %.

### Claim 11 (depends on 6)

The method of claim 6, further comprising a step of filtering the copper sulfate electrolyte by using an activated carbon filter prior to the step of performing the electrochemical reaction on the copper sulfate electrolyte added with the hydrogen peroxide solution.