Secondary battery, process for preparing the same and apparatus containing the secondary battery

1. A secondary battery ( 5 ), comprising a negative electrode plate ( 10 ), wherein the negative electrode plate ( 10 ) comprises a negative electrode current collector ( 101 ) and a negative electrode film ( 102 , 103 ), and the negative electrode film ( 102 , 103 ) comprises a first negative electrode film ( 103 ) and a second negative electrode film ( 102 );

the first negative electrode film ( 103 ) is disposed on at least one surface of the negative electrode current collector ( 101 ) and comprises a first negative electrode active material;

the second negative electrode film ( 102 ) is disposed on the first negative electrode film ( 103 ) and comprises a second negative electrode active material;

the first negative electrode active material and the second negative electrode active material both comprise artificial graphite;

the first negative electrode active material comprises primary particles, and a number percentage of the primary particles in the first negative electrode active material A satisfies A≥50%, and

the second negative electrode active material comprises secondary particles, and a number percentage of the secondary particles in the second negative electrode active material B satisfies: B≥30%; and

a volume distribution particle size DV50 of the first negative electrode active material is greater than a volume distribution particle size DV50 of the second negative electrode active material.

2. The secondary battery ( 5 ) according to claim 1 , wherein A≥70%.

3. The secondary battery ( 5 ) according to claim 1 , wherein B≥50%.

4. The secondary battery ( 5 ) according to claim 1 , wherein a volume distribution particle size DV10 of the first negative electrode active material is smaller than a volume distribution particle size DV10 of the second negative electrode active material.

5. The secondary battery ( 5 ) according to claim 4 , wherein the volume distribution particle size DV10 of the first negative electrode active material is from 3 μm to 8 μm; and/or,

the volume distribution particle size DV10 of the second negative electrode active material is from 5 μm to 11 μm.

6. The secondary battery ( 5 ) according to claim 4 , wherein the volume distribution particle size DV10 of the first negative electrode active material is from 4 μm to 7 μm; and/or,

the volume distribution particle size DV10 of the second negative electrode active material is from 6 μm to 10 μm.

7. The secondary battery ( 5 ) according to claim 1 , wherein a tap density of the first negative electrode active material is greater than a tap density of the second negative electrode active material.

8. The secondary battery ( 5 ) according to claim 7 , wherein the tap density of the first negative electrode active material is from 0.8 g/cm 3 to 1.3 g/cm 3 ; and/or,

the tap density of the second negative electrode active material is from 0.7 g/cm 3 to 1.2 g/cm 3 .

9. The secondary battery ( 5 ) according to claim 1 , wherein the volume distribution particle size DV50 of the first negative electrode active material is from 13 μm to 21 μm; and/or,

the volume distribution particle size DV50 of the second negative electrode active material is from 11 μm to 19 μm.

10. The secondary battery according to claim 1 , wherein a graphitization degree of the first negative electrode active material is greater than a graphitization degree of the second negative electrode active material.

11. The secondary battery ( 5 ) according to claim 10 , wherein the graphitization degree of the first negative electrode active material is from 92% to 97%; and/or,

the graphitization degree of the second negative electrode active material is from 90% to 95%.

12. The secondary battery ( 5 ) according to claim 1 , wherein

the first negative electrode active material has a specific surface area (SSA) of from 1.6 m 2 /g to 2.6 m 2 /g; and/or,

the second negative electrode active material has a specific surface area (SSA) of from 0.7 m 2 /g to 1.5 m 2 /g.

13. The secondary battery ( 5 ) according to claim 1 , wherein the artificial graphite is present in the first negative electrode active material in a mass percentage of ≥50%; and/or,

The artificial graphite is present in the second negative electrode active material in a mass percentage of ≥80%.

14. The secondary battery ( 5 ) according to claim 1 , wherein 80%≤A≤100%.

15. The secondary battery ( 5 ) according to claim 1 , wherein

the volume distribution particle size DV50 of the first negative electrode active material is from 15 μm to 19 μm; and/or,

the volume distribution particle size DV50 of the second negative electrode active material is from 13 μm to 17 μm.

16. An apparatus, comprising the secondary battery ( 5 ) according to claim 1 .

17. A process for preparing a secondary battery ( 5 ), comprising preparing a negative electrode plate ( 10 ) of the secondary battery by the following steps:

1) forming a first negative electrode film ( 103 ) comprising a first negative electrode active material on at least one surface of a negative electrode current collector ( 10 ); and

2) forming a second negative electrode film ( 102 ) comprising a second negative electrode active material on the first negative electrode film ( 103 ),

wherein the first and second negative electrode active material both comprise artificial graphite; the first negative electrode active material comprises primary particles, a number percentage of the primary particles in the first negative electrode active material A satisfies A≥50%, and the second negative electrode active material comprises secondary particles, and a number percentage of the secondary particles in the second negative electrode active material B satisfies: B≥30%; and

a volume distribution particle size DV50 of the first negative electrode active material is greater than a volume distribution particle size DV50 of the second negative electrode active material.

18. An apparatus, comprising the secondary battery ( 5 ) manufactured by the process according to claim 17 .