ANODE FOR LITHIUM SECONDARY BATTERY AND LITHIUM SECONDARY BATTERY INCLUDING THE SAME

• US 20140287316A1
• Filed: 06/06/2014
• Published: 09/25/2014
• Est. Priority Date: 01/25/2013
• Status: Active Grant

• Current Assignee: LG Energy Solution Limited (LG Corporation)
• Original Assignee: LG Chem Limited (LG Corporation)
• Inventors: Ahn, Byoung Hoon, Bae, Joon Sung, Koo, Chang Wan
• Granted Patent: US 9,583,756 B2
• Time in Patent Office: Days
• US Class Current: 429/231.8
• CPC Class Codes: H01M 10/052 Li-accumulators
• CPC Class Codes: H01M 10/0525 Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• CPC Class Codes: H01M 2004/021 Physical characteristics, e.g. porosity, surface area
• CPC Class Codes: H01M 2220/20 Batteries in motive systems, e.g. vehicle, ship, plane
• CPC Class Codes: H01M 4/0404 by coating on electrode collectors
• CPC Class Codes: H01M 4/0435 Rolling or calendering
• CPC Class Codes: H01M 4/133 Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
• CPC Class Codes: H01M 4/1393 of electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
• CPC Class Codes: H01M 4/366 as layered products
• CPC Class Codes: H01M 4/583 Carbonaceous material, e.g. graphite-intercalation compounds or CFx
• CPC Class Codes: H01M 4/587 for inserting or intercalating light metals
• CPC Class Codes: H01M 4/622 being polymers
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y10T 29/49117 Conductor or circuit manufacturing

Abstract

Provided is an anode for a lithium secondary battery composed of a multi-layered structure including an electrode current collector, a first anode active material layer including a first anode active material formed on the electrode current collector, and a second anode active material layer including a second anode active material having relatively lower press density and relatively larger average particle diameter than the first anode active material.

Since an anode according to an embodiment of the present invention may include a multi-layered active material layer including two kinds of anode active materials having different press densities and average particle diameters on an electrode current collector, porosity of the surface of the electrode may be improved even after a press process to improve ion mobility into the electrode. Thus, charge characteristics and cycle life of a lithium secondary battery may be improved.

Claims

1. An anode comprising:

an electrode current collector; and

a multi-layered active material layer formed on the electrode current collector,

wherein the multi-layered active material layer comprises;

a first anode active material layer including a first anode active material; and

a second anode active material layer including a second anode active material having a lower press density and a larger average particle diameter than the first anode active material.

2. The anode of claim 1, wherein the first anode active material and the second anode active material each comprises crystalline carbon, amorphous carbon, or a mixture thereof.

3. The anode of claim 1, wherein the first anode active material and the second anode active material each comprises natural graphite, artificial graphite, or a mixture thereof, which has a spherical or spherical-like shape.

4. The anode of claim 1, wherein a ratio of the average particle diameter of the first anode active material to the average particle diameter of the second anode active material is in a range of 1:

9 to 5;

5.1.

5. The anode of claim 4, wherein the ratio of the average particle diameter of the first anode active material to the average particle diameter of the second anode active material is in a range of 1:

1.3 to 1;

4.

6. The anode of claim 1, wherein a ratio of the press density of the first anode active material to the press density of the second anode active material is in a range of 1.1:

1 to 3;

1 under a pressure of 12 MPa to 16 MPa.

7. The anode of claim 1, wherein a ratio of compressive strength of the first anode active material to compressive strength of the second anode active material is in a range of 2:

8 to 5;

5.1 under a pressure of 12 MPa to 16 MPa.

8. The anode of claim 1, wherein porosity of the second anode active material layer is higher than porosity of the first anode active material layer.

9. The anode of claim 1, wherein the first anode active material and the second anode active material each further comprise a conductive agent and a binder.

15. A lithium secondary battery comprising the anode of claim 1.

10. A method of preparing an anode, the method comprising:

coating an electrode current collector with a first anode active material slurry including a first anode active material and a binder resin;

forming a first anode active material layer by drying the first anode active material slurry;

coating the first anode active material layer with a second anode active material slurry including a second anode active material and a binder resin;

forming a second anode active material layer by drying the second anode active material slurry; and

pressing the electrode current collector on which the first and second anode active material layers are formed.

12. The method of claim 10, wherein porosity of the second anode active material layer is relatively higher than porosity of the first anode active material layer.

13. The method of claim 12, wherein a ratio of the porosity of the first anode active material layer to the porosity of the second anode active material layer before press is in a range of 5:

5.1 to 4;

6.

14. The method of claim 12, wherein a ratio of the porosity of the first anode active material layer to the porosity of the second anode active material layer after press is in a range of 5:

5.1 to 2;

8.

11. A method of preparing an anode, the method comprising:

coating an electrode current collector with a first anode active material slurry including a first anode active material and a binder resin;

coating the first anode active material layer with a second anode active material slurry including a second anode active material and a binder resin;

forming a multi-layered anode active material layer by drying the first and second anode active material slurries; and

pressing the electrode current collector on which the multi-layered anode active material layer is formed.