Electrolytic copper foil, method for producing the same, and lithium ion secondary battery

Patent metadata

Field	Value
Publication number	US-2020350620-A1
Application number	US-202016844050-A
Country	US
Kind code	A1
Filing date	Apr 9, 2020
Priority date	Apr 30, 2019
Publication date	Nov 5, 2020
Grant date	—

Abstract

An electrolytic copper foil includes a raw foil layer having a first surface and a second surface opposite to the first surface. In the X-ray diffraction spectrum of the first surface, a ratio of the diffraction peak intensity I(200) of the (200) crystal face of the first surface relative to the diffraction peak intensity I(111) of the (111) crystal face of the first surface is between 0.5 and 2.0. In the X-ray diffraction spectrum of the second surface, a ratio of the diffraction peak intensity I(200) of the (200) crystal face of the second surface relative to the diffraction peak intensity I(111) of the (111) crystal face of the second surface is also between 0.5 and 2.0. A method for producing the electrolytic copper foil, and a lithium ion secondary battery is also provided.

First claim

What is claimed is:

1 . An electrolytic copper foil, comprising:
a raw foil layer having a first surface and a second surface opposite to the first surface; wherein in the X-ray diffraction spectrum of the first surface, a ratio of the diffraction peak intensity I(200) of the (200) crystal face of the first surface relative to the diffraction peak intensity I(111) of the (111) crystal face of the first surface is between 0.5 and 2.0; wherein in the X-ray diffraction spectrum of the second surface, a ratio of the diffraction peak intensity I(200) of the (200) crystal face of the second surface relative to the diffraction peak intensity I(111) of the (111) crystal face of the second surface is between 0.5 and 2.0.

2 . The electrolytic copper foil according to claim 1 , wherein a distance between the first surface and the second surface is defined as a thickness of the electrolytic copper foil, and the thickness is between 2 μm and 20 μm.

3 . The electrolytic copper foil according to claim 1 , wherein without a heat treatment step, the electrolytic copper foil has a tensile strength between 28 kgf/mm 2 and 40 kgf/mm 2 and an elongation not less than 7%.

4 . The electrolytic copper foil according to claim 3 , wherein after the heat treatment step, the electrolytic copper foil has a tensile strength between 25 kgf/mm 2 and 35 kgf/mm 2 and an elongation not less than 9.5%; wherein the heat treatment step includes: baking the electrolytic copper foil at a temperature between 130° C. and 250° C. for 0.5 hours to 1.5 hours.

5 . The electrolytic copper foil according to claim 1 , wherein a tensile strength of the electrolytic copper foil that is treated by a heat treatment step is between 65% and 95% of a tensile strength of the electrolytic copper foil that is not treated by the heat treatment step, and an elongation of the electrolytic copper foil that is treated by the heat treatment step is between 100% and 140% of an elongation of the electrolytic copper foil that is not treated by the heat treatment step.

6 . The electrolytic copper foil according to claim 1 , further comprising:
a first oxidation resistant layer disposed on the first surface; and a second oxidation resistant layer disposed on the second surface; wherein based on the total weight of the electrolytic copper foil, each of the first oxidation resistant layer and the second oxidation resistant layer includes a non-copper metal element in an amount ranging from 1 ppm to 1,000 ppm; wherein the non-copper metal element is at least one element selected from the group consisting of chromium, zinc, nickel, molybdenum, manganese, phosphorus, and combinations thereof.

7 . The electrolytic copper foil according to claim 1 , wherein the first surface is a surface that is in contact with a rotating electrode drum during a plating process and is defined as an S surface; and the second surface is a surface that is opposite to the S surface and is defined as an M surface; wherein in the X-ray diffraction spectrum of the S surface, a ratio of the diffraction peak intensity I(200) of the (200) crystal face of the S surface relative to the diffraction peak intensity I(111) of the (111) crystal face of the S surface is defined as a first diffraction peak intensity ratio; and in the X-ray diffraction spectrum of the M surface, a ratio of the diffraction peak intensity I(200) of the (200) crystal face of the M surface relative to the diffraction peak intensity I(111) of the (111) crystal face of the M surface is defined as a second diffraction peak intensity ratio; wherein the first diffraction peak intensity ratio is less than the second diffraction peak intensity ratio.

8 . The electrolytic copper foil according to claim 7 , wherein an absolute value of a difference between the first diffraction peak intensity ratio and the second diffraction peak intensity ratio is not less than 0.01 and not more than 0.30.

9 . The electrolytic copper foil according to claim 1 , further comprising a plurality of crystal grains distributed between the first surface and the second surface; wherein without heat treatment step, each crystal grain has a grain size between 20 nm and 45 nm; wherein a grain size of each crystal grain that is treated by the heat treatment step is between 90% and 130% of a grain size of each crystal grain that is not treated by the heat treatment step.

10 . A method for producing an electrolytic copper foil, comprising:
preparing a copper electrolytic solution including at least one addition agent; wherein based on a total weight of the copper electrolytic solution, a concentration of the at least one addition agent is not more than 12 ppm; and performing an electroplating step including: electrolyzing the copper electrolytic solution to form a raw foil layer; wherein the raw foil layer has a first surface and a second surface opposite to the first surface; wherein in the X-ray diffraction spectrum of the first surface, a ratio of the diffraction peak intensity I(200) of the (200) crystal face of the first surface relative to the diffraction peak intensity I(111) of the (111) crystal face of the first surface is between 0.5 and 2.0; wherein in the X-ray diffraction spectrum of the second surface, a ratio of the diffraction peak intensity I(200) of the (200) crystal face of the second surface relative to the diffraction peak intensity I(111) of the (111) crystal face of the second surface is between 0.5 and 2.0.

11 . The method according to claim 10 , wherein the at least one addition agent includes a first addition agent, a second addition agent, and a third addition agent; wherein the first addition agent is a gelatin, the second addition agent is sulfonic acid or sulfonate which has a sulfur compound, and the third addition agent is a nonionic water soluble polymer.

12 . The method according to claim 11 , wherein in the copper electrolytic solution, a sum of concentrations of the first addition agent, the second addition agent, and the third addition agent is not more than 12 ppm.

13 . The method according to claim 11 , wherein the gelatin has a weight average molecular weight between 1,000 and 5,000.

14 . The method according to claim 10 , further comprising:
performing an anti-oxidation treatment step which includes: forming a first oxidation resistant layer on the first surface of the raw foil layer, and forming a second oxidation resistant layer on the second surface of the raw foil layer, such that the raw foil layer, the first oxidation resistant layer, and the second oxidation resistant layer are collectively formed into an electrolytic copper foil; wherein based on a total weight of the electrolytic copper foil, each of the first oxidation resistant layer and the second oxidation resistant layer includes a non-copper metal element in an amount ranging from 1 ppm to 1,000 ppm; wherein the non-copper metal element is at least one element selected from the group consisting of chromium, zinc, nickel, molybdenum, manganese, phosphorus, and combinations thereof.

15 . A lithium ion secondary battery, comprising:
an electrolytic tank having an accommodating space for accommodating an electrolytic solution; a positive electrode disposed in the accommodating space of the electrolytic tank; a negative electrode disposed in the accommodating space of the electrolytic tank and spaced apart from the positive electrode; wherein the negative electrode includes an electrolytic copper foil, and the electrolytic copper foil has a first surface and a second surface opposite to the first surface; and an isolation film disposed between the p

Assignees

• Nanya Plastics Corp

Inventors

• Chen Chia-Ling
• Tzou Ming-Jen

Classifications

• H01M4/045

  Electrochemical coating; Electrochemical impregnation · CPC title

• H01M2300/0025

  Organic electrolyte · CPC title

• H01M4/667

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

• C25D3/42

  of light metals · CPC title

• C25D3/54

  of metals not provided for in groups C25D3/04 - C25D3/50 · CPC title