Negative electrode for lithium secondary battery and lithium secondary battery comprising same

Patent metadata

Field	Value
Publication number	US-11735741-B2
Application number	US-202217930715-A
Country	US
Kind code	B2
Filing date	Sep 8, 2022
Priority date	Nov 7, 2017
Publication date	Aug 22, 2023
Grant date	Aug 22, 2023

Abstract

A negative electrode for a lithium secondary battery comprises a current collector and a negative electrode active material layer formed on the current collector, wherein the negative electrode active material layer includes a first negative electrode active material and a first binder, and a second active material layer formed on the first active material layer and including a second negative electrode active material and a second binder, a content of the first binder is greater than that of the second binder, a loading level of the negative electrode active material layer is 10 mg/cm 2 to 30 mg/cm 2 , a loading level of the first active material layer is 4 mg/cm 2 to 25 mg/cm 2 , a loading level of the second active material layer is 4 mg/cm 2 to 25 mg/cm 2 , and a loading level of the second active material layer is equal to or higher than that of the first active material layer.

First claim

What is claimed is:

1. A lithium secondary battery comprising:
a negative electrode comprising:
a current collector and
a negative electrode active material layer on the current collector,
wherein the negative electrode active material layer comprises:
a first active material layer comprising a first active material and a first binder,
a second active material layer on the first active material layer and comprising a second active material and a second binder, a content of the first binder being greater than a content of the second binder, and
a conductive layer between the first active material layer and the second active material layer;

a positive electrode; and
an electrolyte comprising a mixed non-aqueous organic solvent of ethylene carbonate and propylene carbonate, ethylene propionate.

2. The lithium secondary battery of claim 1 , wherein the content of the first binder is 1 wt % to 10 wt % based on a total weight of the first active material layer.

3. The lithium secondary battery of claim 1 , wherein the content of the second binder is 0.5 wt % to 10 wt % based on a total weight of the second active material layer.

4. The lithium secondary battery of claim 1 , wherein a ratio of the content of the second binder to the content of the first binder is more than 0 and less than 1.

5. The lithium secondary battery of claim 1 , wherein a ratio of a loading level of the first active material layer to a loading level of the second active material layer is 1:1 to 1:7.

6. The lithium secondary battery of claim 1 , wherein at least one selected from among the first active material layer and the second active material layer further comprises a conductive material.

7. The lithium secondary battery of claim 1 , wherein the first binder and the second binder are respectively non-aqueous binders or aqueous binders.

8. The lithium secondary battery of claim 1 , wherein at least one selected from among the first binder and the second binder is an aqueous binder.

9. The lithium secondary battery of claim 1 , wherein a pellet density of each of the first active material of the first active material layer and the second active material of the second active material layer is 1.1 g/cc to 2.0 g/cc.

10. The lithium secondary battery of claim 1 , wherein a pellet density of the second active material of the second active material layer is smaller than a pellet density of the first active material of the first active material layer by 0.01 g/cc to 0.5 g/cc.

11. The lithium secondary battery of claim 1 , wherein the conductive layer comprises a conductive material, a thickener and a solvent.

12. The lithium secondary battery of claim 11 , wherein a ratio of the conductive material and the thickener is 50 wt % to 90 wt % and 50 wt % to 10 wt %, respectively.

13. The lithium secondary battery of claim 11 , wherein the conductive layer further comprises a binder.

14. The lithium secondary battery of claim 13 , wherein a ratio of the conductive material, the thickener and the binder is 50 wt % to 90 wt %, 5 wt % to 25 wt %, and 0 wt % to 25 wt %, respectively.

15. The lithium secondary battery of claim 1 , wherein the conductive layer comprises an active material.

16. The lithium secondary battery of claim 1 , wherein a thickness of the conductive layer is 0.01 μm to 20.0 μm.

Assignees

• Samsung Sdi Co Ltd

Inventors

• Cha Inoh
• Kim Deok-Hyun
• Lee Jinhee

Classifications

• H01M2004/027

  Negative electrodes · CPC title

• H01M2004/021

  Physical characteristics, e.g. porosity, surface area · CPC title

• H01M10/052

  Li-accumulators · CPC title

• H01M4/621

  Binders · CPC title

• H01M4/13 Primary

  Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof · CPC title