Method for manufacturing negative electrode, negative electrode obtained therefrom and secondary battery including the same

Patent metadata

Field	Value
Publication number	US-12431483-B2
Application number	US-202017772260-A
Country	US
Kind code	B2
Filing date	Nov 17, 2020
Priority date	Nov 18, 2019
Publication date	Sep 30, 2025
Grant date	Sep 30, 2025

Abstract

A method for manufacturing a negative electrode, including the steps of preparing a negative electrode slurry including low-expansion natural graphite, a binder polymer, a conductive material and a dispersion medium; applying the negative electrode slurry to at least one surface of a negative electrode current collector, drying the coated negative electrode slurry, to form a preliminary negative electrode having a preliminary negative electrode active material layer; and pressing the preliminary negative electrode to obtain the negative electrode having a finished negative electrode active material layer. A difference between the specific surface area of the preliminary negative electrode active material layer before pressing and that of the finished negative electrode active material layer after pressing is 0.5 m 2 /g to 1.0 m 2 /g. A negative electrode obtained by the method and a secondary battery including the negative electrode are also disclosed.

First claim

What is claimed is:

1. A method for manufacturing a negative electrode, comprising the steps of:
preparing a negative electrode slurry comprising low-expansion natural graphite, a binder polymer, a conductive material and a dispersion medium;
applying the negative electrode slurry to at least one surface of a negative electrode current collector, and drying the applied negative electrode slurry, to form a preliminary negative electrode having a preliminary negative electrode active material layer; and
pressing the preliminary negative electrode to obtain the negative electrode having a finished negative electrode active material layer,
wherein a difference between a specific surface area of the preliminary negative electrode active material layer before pressing and that of the finished negative electrode active material layer after pressing is 0.5 m 2 /g to 1.0 m 2 /g,
wherein the low-expansion natural graphite has a difference in particle size between D 90 and D 10 of 10 μm or less, wherein D 90 is a particle diameter at a point of 90% in the particle size cumulative distribution as a function of particle diameter in a laser diffraction particle size analyzer, and D 10 is a particle diameter at a point of 10% in the particle size cumulative distribution as a function of particle diameter in the laser diffraction particle size analyzer, and
wherein the low-expansion natural graphite has a total pore volume of 10 cm 3 /g to 20 cm 3 /g.

2. The method for manufacturing the negative electrode according to claim 1 , wherein the difference between the specific surface area of the preliminary negative electrode active material layer before pressing and that of the finished negative electrode active material layer after pressing is 0.6 m 2 /g to 0.9 m 2 /g.

3. The method for manufacturing the negative electrode according to claim 1 , wherein the low-expansion natural graphite has a difference in particle size between D 90 and D 10 of 5 μm to 10 μm.

4. The method for manufacturing the negative electrode according to claim 1 , wherein the low-expansion natural graphite has a total pore volume of 12 cm 3 /g to 18 cm 3 /g.

5. The method for manufacturing the negative electrode according to claim 1 , wherein the difference of I004/I110 in degree of orientation between the preliminary negative electrode active material layer before pressing and the finished negative electrode active material layer after pressing is 4 to 8.

6. The method for manufacturing the negative electrode according to claim 5 , wherein the difference of I004/I110 in degree of orientation between the preliminary negative electrode active material layer before pressing and the finished negative electrode active material layer after pressing is 5 to 7.

7. A negative electrode obtained by the method as defined in claim 1 .

8. A secondary battery, comprising:
the negative electrode as defined in claim 7 ;
a positive electrode; and
a separator interposed between the negative electrode and the positive electrode.

9. The secondary battery according to claim 8 , wherein the positive electrode comprises a lithium cobalt oxide.

10. The secondary battery according to claim 8 , which is a pouch-type secondary battery.

Assignees

• Lg Energy Solution Ltd

Inventors

• Choi Hee-Won
• Noh Tae-Gyun
• Jo Mi-Ru
• Park Chan-Ki

Classifications

• H01M10/0525

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

• H01M4/624

  Electric conductive fillers · CPC title

• H01M4/622 Primary

  being polymers · CPC title

• H01M2004/027

  Negative electrodes · CPC title

• H01M2004/021

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