Secondary battery, and battery module, battery pack and apparatus comprising the same

Patent metadata

Field	Value
Publication number	US-12355076-B2
Application number	US-202117512103-A
Country	US
Kind code	B2
Filing date	Oct 27, 2021
Priority date	Dec 4, 2019
Publication date	Jul 8, 2025
Grant date	Jul 8, 2025

Abstract

The embodiments of this application provide a secondary battery, and a battery module, a battery pack and an apparatus including the same. Specifically, this application provides a secondary battery, which includes a negative electrode plate. The negative electrode plate includes a negative electrode current collector and a negative electrode film disposed on at least one surface of the negative electrode current collector. The negative electrode film includes a negative electrode active material, a conductive agent, and a binder. The negative electrode active material includes SiOx (0<x<2) and graphite. An average particle diameter Dv50 of the negative electrode active material is from 8 μm to 14 μm. The conductive agent includes carbon nanotubes whose aspect ratio is greater than or equal to 2500:1. The secondary battery can have both good rate performance and cycle performance under the premise of a relatively high energy density.

First claim

What is claimed is:

1. A secondary battery, comprising a negative electrode plate, wherein the negative electrode plate comprises a negative electrode current collector and a negative electrode film disposed on at least one surface of the negative electrode current collector, and the negative electrode film comprises a negative electrode active material, a conductive agent and a binder,
the negative electrode active material comprises particles comprising particles of SiOx (0<x<2) and particles of graphite, wherein the particles of SiOx and the particles of graphite are physically mixed together;
the average particle diameter Dv50 of the particles of SiOx is from 5 μm to 8 μm;
the average particle diameter Dv50 of the particles of graphite is from 10 μm to 20 μm;
the average particle diameter Dv50 of the particles of the negative electrode active material is from 8 μm to 14 μm;
and the conductive agent comprises carbon nanotubes whose aspect ratio is greater than (3000:1) and less than or equal to (20000:1).

2. The secondary battery according to claim 1 , wherein the carbon nanotubes are single-walled carbon nanotubes (SWCNTs).

3. The secondary battery according to claim 1 , wherein a mass proportion of the carbon nanotubes in the negative electrode film is 0.3% to 1%.

4. The secondary battery according to claim 1 , wherein the binder comprises polyacrylate.

5. The secondary battery according to claim 1 , wherein a weight content of the binder in the negative electrode film is from 3% to 9%.

6. The secondary battery according to claim 1 , wherein a mass percentage content W of the SiOx (0<x<2) in the negative electrode active material is 15%≤W≤40%.

7. The secondary battery according to claim 1 , wherein the graphite comprises artificial graphite.

8. The secondary battery according to claim 1 , wherein a thickness of the negative electrode current collector is from 4 μm to 10 μm.

9. The secondary battery according to claim 1 , wherein a range of surface roughness Ra of the negative electrode current collector is 1.6 μm≤Ra≤3.2 μm.

10. The secondary battery according to claim 1 , wherein an adhesion F between the negative electrode film and the negative electrode current collector is 10 N/m≤F≤90 N/m.

11. The secondary battery according to claim 1 , wherein a thickness of the negative electrode current collector is from 4 μm to 10 μm;
a range of surface roughness Ra of the negative electrode current collector is 1.6 μm≤Ra≤3.2 μm;
and an adhesion F between the negative electrode film and the negative electrode current collector is 10 N/m≤F≤90 N/m.

12. The secondary battery according to claim 1 , wherein a compacted density PD of the negative electrode film is 1.6 g/cm 3 ≤PD≤2.0 g/cm 3 .

13. The secondary battery according to claim 1 , wherein a coating weight CW of the negative electrode film is 0.045 mg/mm 2 ≤CW≤0.09 mg/mm 2 .

14. The secondary battery according to claim 1 , wherein the secondary battery comprises a positive electrode plate, the positive electrode plate comprises a positive electrode current collector and a positive electrode film disposed on at least one surface of the positive electrode current collector and comprising a positive electrode active material, the positive electrode active material comprises Li 1+y Ni a Co b M c O 2−z A z , wherein −0.2≤y≤0.2, 0.5≤a<1, 0<b≤0.3, 0<c≤0.2, 0≤z<0.2, and M is selected from the group consisting of one or more of Mn and Al, and A is selected from the group consisting of one or more of S, N, F, Cl, Br and I.

15. The secondary battery according to claim 1 , wherein the carbon nanotubes whose aspect ratio is greater than (2800:1) and less than or equal to (10000:1).

16. The secondary battery according to claim 1 , wherein an adhesion F between the negative electrode film and the negative electrode current collector is 30 N/m≤F≤80 N/m.

17. The secondary battery according to claim 16 , wherein an adhesion F between the negative electrode film and the negative electrode current collector is 30 N/m≤F≤50 N/m.

18. A battery module, comprising:
a secondary battery, comprising a negative electrode plate, wherein the negative electrode plate comprises a negative electrode current collector and a negative electrode film disposed on at least one surface of the negative electrode current collector, and the negative electrode film comprises a negative electrode active material, a conductive agent and a binder,
the negative electrode active material comprises particles comprising particles of SiOx (0<x<2) and particles of graphite, wherein the particles of SiOx and the particles of graphite are physically mixed together;
the average particle diameter Dv50 of the particles of SiOx is from 5 μm to 8 μm;
the average particle diameter Dv50 of the particles of graphite is from 10 μm to 20 μm;
the average particle diameter Dv50 of the particles of the negative electrode active material is from 8 μm to 14 μm;
and the conductive agent comprises carbon nanotubes whose aspect ratio is greater than (3000:1) and less than or equal to (20000:1).

19. An apparatus, comprising:
a secondary battery, comprising a negative electrode plate, wherein the negative electrode plate comprises a negative electrode current collector and a negative electrode film disposed on at least one surface of the negative electrode current collector, and the negative electrode film comprises a negative electrode active material, a conductive agent and a binder,
the negative electrode active material comprises particles comprising particles of SiOx (0<x<2) and particles of graphite, wherein the particles of SiOx and the particles of graphite are physically mixed together;
the average particle diameter Dv50 of the particles of SiOx is from 5 μm to 8 μm;
the average particle diameter Dv50 of the particles of graphite is from 10 μm to 20 μm;
the average particle diameter Dv50 of the particles of the negative electrode active material is from 8 μm to 14 μm;
and the conductive agent comprises carbon nanotubes whose aspect ratio is greater than (3000:1) and less than or equal to (20000:1).

Assignees

• Contemporary Amperex Technology Hong Kong Ltd

Inventors

• Wang Danfeng
• Yan Chuanmiao

Classifications

• H01M4/64

  Carriers or collectors · CPC title

• H01M4/131

  Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx · CPC title

• H01M10/0525

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

• H01M4/364

  as mixtures · CPC title

• H01M4/133

  Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx · CPC title