Electrode having enhanced adhesion for lithium secondary batteries

Patent metadata

Field	Value
Publication number	US-2016099470-A1
Application number	US-201514872242-A
Country	US
Kind code	A1
Filing date	Oct 1, 2015
Priority date	Oct 6, 2014
Publication date	Apr 7, 2016
Grant date	—

Abstract

Disclosed is an electrode for secondary batteries including an electrode mix, which includes an electrode active material and a binder, coated on a current collector. More particularly, the electrode includes a first electrode mix layer including a first binder, a glass transition temperature (Tg) of which is lower than that of a second binder, and an electrode active material, and coated on the current collector; and a second electrode mix layer including the second binder, a glass transition temperature (Tg) of which is higher than that of the first binder, and an electrode active material, and coated on the first electrode mix layer.

First claim

1 . An electrode for secondary batteries comprising an electrode mix, which comprises an electrode active material and a binder, coated on a current collector, the electrode comprising:
a first electrode mix layer comprising a first binder, a glass transition temperature (Tg) of which is lower than that of a second binder, and an electrode active material, and coated on the current collector; and a second electrode mix layer comprising the second binder, a glass transition temperature (Tg) of which is higher than that of the first binder, and an electrode active material, and coated on the first electrode mix layer.

2 . The electrode according to claim 1 , wherein a thickness of the first electrode mix layer is 10 to 90% a thickness of the second electrode mix layer.

3 . The electrode according to claim 1 , wherein a thickness of the first electrode mix layer is 30 to 70% a thickness of the second electrode mix layer.

4 . The electrode according to claim 1 , wherein the electrode active material of the first electrode mix layer is the same as the electrode active material of the second electrode mix layer.

5 . The electrode according to claim 1 , wherein a content of the first binder in the first electrode mix layer is 1 to 15% by weight based on a total weight of the first electrode mix layer, and a content of the second binder in the second electrode mix layer is 1 to 15% by weight based on a total weight of the second electrode mix layer.

6 . The electrode according to claim 1 , wherein each of the first electrode mix layer and the second electrode mix layer further comprises an electrically conductive material.

7 . The electrode according to claim 6 , wherein, in each of the first binder and the second binder, a content of the conductive material is 20 to 100 parts by weight based on 100 parts by weight of each of the first binder and the second binder.

8 . An electrode for secondary batteries comprising an electrode mix, which comprises an electrode active material and a binder, coated on a current collector, the electrode comprising:
a primer coating layer comprising a first binder, a glass transition temperature (Tg) of which is lower than that of a second binder, and a conductive material, and coated on the current collector; and an electrode mix layer comprising the second binder, a glass transition temperature (Tg) of which is higher than that of the first binder, and an electrode active material, and coated on the primer coating layer.

9 . The electrode according to claim 8 , wherein a thickness of the primer coating layer is 0.1 to 3.0 μm.

10 . The electrode according to claim 8 , wherein a content of the first binder in the primer coating layer is 50 to 85% by weight based on a total weight of the primer coating layer, and a content of the second binder in the electrode mix layer is 1 to 15% by weight based on the total weight of a electrode mix layer.

11 . The electrode according to claim 8 , wherein the primer coating layer further comprises an electrically conductive material.

12 . The electrode according to claim 11 , wherein a content of the conductive material is 20 to 100 parts by weight based on 100 parts by weight of the first binder.

13 . The electrode according to claim 1 , wherein the glass transition temperature (Tg) of the first binder is 15° C. or less, and the glass transition temperature (Tg) of the second binder is 10° C. higher than the glass transition temperature of the first binder.

14 . The electrode according to claim 13 , wherein the glass transition temperature (Tg) of the second binder is 10° C. to less than 25° C. in the range that the glass transition temperature (Tg) of the second binder is higher than that of the first binder.

15 . The electrode according to claim 1 , wherein the first binder and the second binder are the same.

16 . The electrode according to claim 15 , wherein number average molecular weights of the first binder and the second binder are different.

17 . The electrode according to claim 1 , wherein the first binder is different from the second binder.

18 . The electrode according to claim 17 , wherein the first binder is a polymer of monomers comprising a styrene monomer (SM) and butyl acrylate (BA).

19 . The electrode according to claim 17 , wherein the second binder is a polymer of monomers comprising a styrene monomer (SM) and butadiene (BD).

20 . The electrode according to claim 1 , wherein the electrode is a negative electrode and the electrode active material comprises a Si-based material.

21 . The electrode according to claim 20 , wherein the Si-based material is one or more selected from the group consisting of SiO x , where 0.5≦x≦2, Si alloy and amorphous Si.

22 . A method of manufacturing the electrode for secondary batteries according to claim 1 , the method comprising:
forming a first electrode mix layer by drying after spreading a slurry comprising a first binder and an electrode active material on a current collector; forming a second electrode mix layer by drying after spreading a slurry comprising a second binder and an electrode active material on the first electrode mix layer; and drying and rolling the first electrode mix layer and the second electrode mix layer.

23 . A method of manufacturing the electrode for secondary batteries according to claim 8 , the method comprising:
forming a primer coating layer by drying after spreading a slurry comprising a first binder and a conductive material on a current collector; forming an electrode mix layer by drying after spreading a slurry comprising a second binder and an electrode active material on the primer coating layer; and drying and rolling the primer coating layer and the electrode mix layer.

24 . A lithium secondary battery comprising the electrode for secondary batteries according to claim 1 .

25 . A battery module comprising the lithium secondary battery according to claim 24 as a unit cell.

26 . A battery pack comprising the battery module according to claim 25 .

27 . A device comprising the battery pack according to claim 26 as a power source.

28 . The device according to claim 27 , wherein the device is an electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle or an energy storage system.

Assignees

• Lg Chemical Ltd

Inventors

• Kwon Jiyoon
• Kim Kyoungho
• Choi Cheolhoon
• Hah Hoejin
• Kim Seok Koo
• Song Jooyong

Classifications

• H01M4/0435

  Rolling or calendering · CPC title

• H01M4/366

  as layered products · CPC title

• H01M4/134 Primary

  Electrodes based on metals, Si or alloys · CPC title

• H01M2004/027

  Negative electrodes · CPC title

• H01M4/622 Primary

  being polymers · CPC title