Electrolytic copper foil, electrode comprising the same, secondary battery comprising the same, and method for manufacturing the same

Patent metadata

Field	Value
Publication number	US-2018062180-A1
Application number	US-201715661309-A
Country	US
Kind code	A1
Filing date	Jul 27, 2017
Priority date	Aug 23, 2016
Publication date	Mar 1, 2018
Grant date	—

Abstract

An electrolytic copper foil capable of securing a secondary battery having a high capacity retention rate, an electrode including the same, a secondary battery including the same, and a method of manufacturing the same. The electrolytic copper foil, which includes a first surface and a second surface opposite to the first surface, includes a copper layer including a matte surface facing the first surface and a shiny surface facing the second surface, and a first protective layer on the matte surface of the copper layer, wherein the first protective layer includes chromium (Cr) and the first surface of the electrolytic copper foil has an adhesion factor of 1.5 to 16.3.

First claim

What is claimed is:

1 . A secondary battery electrolytic copper foil, which includes a first surface and a second surface opposite the first surface, the electrolytic copper foil comprising:
a copper layer including a matte surface facing the first surface and a shiny surface facing the second surface; and a first protective layer on the matte surface of the copper layer, wherein: the first protective layer comprises chromium (Cr); an adhesion factor of the first surface, which is defined by Equation 1 below, ranges from 1.5 to 16.3:
ADF=Pc/10+DA Cr /(mg/m 2 )+R max /μm  Equation 1:

wherein, ADF denotes an adhesion factor, Pc denotes a peak count, DA Cr denotes an amount of chromium (Cr) electrodeposition (mg/m 2 ), and R max denotes a maximum surface roughness (μm); a Pc of the first surface ranges from 5 to 110; a DA Cr of the first surface ranges from 0.5 to 3.8 mg/m 2 ; and a R max of the first surface ranges from 0.4 to 3.5 μm.

2 . The electrolytic copper foil of claim 1 , further comprising a second protective layer on the shiny surface of the copper layer,
wherein: the second protective layer comprises chromium (Cr); and the second surface has an adhesion factor of 1.5 to 16.3.

3 . The electrolytic copper foil of claim 2 , wherein:
a Pc of the second surface ranges from 5 to 110; a DA Cr of the second surface ranges from 0.5 to 3.8 mg/m 2 ; and a R max of the second surface ranges from 0.4 to 3.5 μm.

4 . The electrolytic copper foil of claim 1 , wherein the electrolytic copper foil has a yield strength of 21 to 63 kgf/mm 2 at room temperature.

5 . The electrolytic copper foil of claim 1 , wherein the electrolytic copper foil has an elongation of 3% or more at room temperature.

6 . A secondary battery electrode comprising:
an electrolytic copper foil including a first surface and a second surface opposite the first surface; and a first active material layer on the first surface of the electrolytic copper foil, wherein: the electrolytic copper foil comprises: a copper layer including a matte surface facing the first surface and a shiny surface facing the second surface; and a first protective layer on the matte surface of the copper layer; the first protective layer comprises chromium (Cr); and an adhesion factor of the first surface of the electrolytic copper foil, which is defined by Equation 1 below, ranges from 1.5 to 16.3:
ADF=Pc/10+DA Cr /(mg/m 2 )+R max /μm  Equation 1:

wherein, ADF denotes an adhesion factor, Pc denotes a peak count, DA Cr denotes an amount of chromium (Cr) electrodeposition (mg/m 2 ), and R max denotes a maximum surface roughness (μm).

7 . The secondary battery electrode of claim 6 , wherein the first active material layer comprises at least one active material selected from a group consisting of carbon, a metal (Me) such as Si, Ge, Sn, Li, Zn, Mg, Cd, Ce, Ni, or Fe, an alloy containing the metal, an oxide of the metal (MeO x ), and a composite of the metal and carbon.

8 . The secondary battery electrode of claim 6 , wherein the first active material layer comprises Si.

9 . The secondary battery electrode of claim 6 , wherein:
the electrolytic copper foil further comprises a second protective layer on the shiny surface of the copper layer; and the secondary battery electrode further comprises a second active material layer on the second protective layer.

10 . The secondary battery electrode of claim 6 , wherein adhesion between the electrolytic copper foil and the first active material layer is 25 N/m or more.

11 . A secondary battery comprising:
a cathode; an anode; an electrolyte configured to provide an environment in which lithium ions may move between the cathode and the anode; and a separator configured to electrically insulate the cathode from the anode, wherein the anode comprises: an electrolytic copper foil including a first surface and a second surface opposite the first surface; and a first active material layer on the first surface of the electrolytic copper foil, wherein the electrolytic copper foil comprises: a copper layer including a matte surface facing the first surface and a shiny surface facing the second surface; and a first protective layer on the matte surface of the copper layer; the first protective layer comprises chromium (Cr); and an adhesion factor of the first surface of the electrolytic copper foil, which is defined by Equation 1 below, ranges from 1.5 to 16.3:
ADF=Pc/10+DA Cr /(mg/m 2 )+R max /μm  Equation 1:

wherein, ADF denotes an adhesion factor, Pc denotes a peak count, DA Cr denotes an amount of chromium (Cr) electrodeposition (mg/m 2 ), and R max denotes a maximum surface roughness (μm).

12 . A method of manufacturing a secondary battery electrolytic copper foil, the method comprising:
forming a copper layer by applying electricity between a positive electrode plate and a rotating negative electrode drum which are disposed in an electrolytic solution containing 70 to 90 g/L of copper ions and 50 to 150 g/L of sulfuric acid to be spaced apart from each other; and forming a protective layer on the copper layer, wherein the forming of the copper layer comprises: performing a heat treatment on a copper wire; pickling the heat-treated copper wire; preparing the electrolytic solution by introducing the pickled copper wire into sulfuric acid; performing electroplating by applying electricity between the positive electrode plate and the rotating negative electrode drum at a current density of 40 to 80 A/dm 2 ; and performing continuous filtration for removing solid impurities from the electrolytic solution at a flow rate of 31 to 45 m 3 /hr while the electroplating is performed, wherein, while the electroplating is performed, total carbon (TC) in the electrolytic solution is maintained at 0.25 g/L or less, and a concentration of silver (Ag) therein is maintained at 0.2 g/L or less, and the forming of the protective layer comprises immersing the copper layer in an antirust solution containing 0.5 to 1.5 g/L of chromium (Cr).

13 . The method of claim 12 , wherein the copper wire is heat-treated at a temperature of 600 to 900° C. for 30 to 60 minutes.

14 . The method of claim 12 , wherein the electrolytic solution further comprises chloride ions capable of precipitating silver (Ag) in the form of AgCl to prevent a concentration of silver (Ag) from exceeding 0.2 g/L by silver (Ag) being introduced into the electrolytic solution while the electroplating is performed.

15 . The method of claim 12 , wherein the forming of the copper layer further comprises introducing hydrogen peroxide and air into the electrolytic solution while the electroplating is performed.

16 . The method of claim 12 , wherein a concentration of copper (Cu) in the antirust solution is maintained at 0.1 g/L or less.

17 . The method of claim 12 , wherein the electrolytic solution further comprises an organic additive selected from a group consisting of hydroxyethyl cellulose (HEC), organic sulfides, organic nitrides, and thiourea-based compounds.

Assignees

• Ls Mtron Ltd

Inventors

• Kim Seung Min

Classifications

• Y10T428/12438

  Composite · CPC title

• C25D3/38

  of copper · CPC title

• H01M4/386

  Silicon or alloys based on silicon · CPC title

• H01M4/667 Primary

  in the form of layers, e.g. coatings · CPC title

• H01M10/0525

  Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries · CPC title