Rolled copper foil for negative electrode current collector of secondary battery, negative electrode of secondary battery and secondary battery using the rolled copper, and method for manufacturing rolled copper foil for negative electrode current collector of secondary battery

Patent metadata

Field	Value
Publication number	US-2019123358-A1
Application number	US-201816165092-A
Country	US
Kind code	A1
Filing date	Oct 19, 2018
Priority date	Oct 19, 2017
Publication date	Apr 25, 2019
Grant date	—

Abstract

The present invention is intended to provide a rolled copper foil for a secondary battery negative electrode current collector which can satisfactorily suppress rupture of the copper foil caused by stress generation or the like due to volume change of an active material. A rolled copper foil for a secondary battery negative electrode current collector, wherein a tensile strength in a direction parallel to the rolling direction is 600 MPa or more, and a breaking elongation in the direction parallel to the rolling direction is 2.0% or more; and wherein a tensile strength in a direction orthogonal to the rolling direction is 640 MPa or more, and a breaking elongation in the direction orthogonal to the rolling direction is 3.5% or more.

First claim

1 . A rolled copper foil for a secondary battery negative electrode current collector,
wherein a tensile strength in a direction parallel to the rolling direction is 600 MPa or more, and a breaking elongation in the direction parallel to the rolling direction is 2.0% or more; and wherein a tensile strength in a direction orthogonal to the rolling direction is 640 MPa or more, and a breaking elongation in the direction orthogonal to the rolling direction is 3.5% or more.

2 . The rolled copper foil for a secondary battery negative electrode current collector according to claim 1 , wherein after a heat treatment at 200° C. for 60 minutes, the tensile strength in the direction parallel to the rolling direction is 600 MPa or more, the breaking elongation in the direction parallel to the rolling direction is 2.0% or more, the tensile strength in the direction orthogonal to the rolling direction is 640 MPa or more, and the breaking elongation in the direction orthogonal to the rolling direction is 3.5% or more.

3 . The rolled copper foil for a secondary battery negative electrode current collector according to claim 1 , wherein a 0.2% yield strength in the direction parallel to the rolling direction is 480 MPa or more, and a 0.2% yield strength in the direction orthogonal to the rolling direction is 510 MPa or more.

4 . The rolled copper foil for a secondary battery negative electrode current collector according to claim 1 , wherein after a heat treatment at 200° C. for 60 minutes, the 0.2% yield strength in the direction parallel to the rolling direction is 480 MPa or more, and the 0.2% yield strength in the direction orthogonal to the rolling direction is 510 MPa or more.

5 . The rolled copper foil for a secondary battery negative electrode current collector according to claim 1 , comprising 0.05 to 0.20 mass % of Sn.

6 . The rolled copper foil for a secondary battery negative electrode current collector according to claim 1 , further comprising 0.01 to 0.10 mass % of Ag.

7 . A secondary battery negative electrode current collector, comprising the rolled copper foil for a secondary battery negative electrode current collector according to claim 1 .

8 . A secondary battery negative electrode, comprising the rolled copper foil for a secondary battery negative electrode current collector according to claim 1 .

9 . A secondary battery, comprising the rolled copper foil for a secondary battery negative electrode current collector according to claim 1 .

10 . A method for manufacturing the rolled copper foil for a secondary battery negative electrode current collector according to claim 1 , the method comprising a step of hot rolling an ingot, and a step of final cold rolling in which the ingot is rolled to a predetermined thickness,
wherein in the step of final cold rolling, a working degree η at the end of each pass and a diameter η (mm) of the work roll used in the pass satisfy the relationship η×r≤250; wherein in the step of final cold rolling, a working ratio of each pass is 24% or more; and a total working ratio is more than 99.9%, (the working degree q is calculated by the following equation:
η=ln( T 0 /T n )  Equation 1

wherein T 0 is the thickness of the ingot before the step of final cold rolling, and T n is the thickness of the ingot at the end of n-th pass.)

11 . The method for manufacturing a rolled copper foil for a secondary battery negative electrode current collector according to claim 10 , further comprising a step of cold rolling and a step of annealing treatment, wherein the step of cold rolling and the step of annealing treatment are performed on the ingot after the hot rolling, and before the step of final cold rolling.

Assignees

• Jx Nippon Mining & Metals Corp

Inventors

• Kudo Katsuhiro

Classifications

• H01M4/662

  Alloys (collectors of lead alloys H01M4/685) · CPC title

• H01M10/0525

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

• H01M2004/027

  Negative electrodes · CPC title

• C22C9/00 Primary

  Alloys based on copper · CPC title

• C22F1/08

  of copper or alloys based thereon · CPC title