Secondary battery, preparation method thereof, and battery module, battery pack, and apparatus containing such secondary battery
A secondary battery, a preparation method thereof, and a battery module, a battery pack, and an apparatus containing such secondary battery are provided. In some embodiments, the secondary battery includes a negative-electrode plate, where the negative-electrode plate includes a negative-electrode current collector and a negative-electrode film layer, the negative-electrode film layer includes a first negative-electrode film layer and a second negative-electrode film layer, and the second negative-electrode film layer is located between the negative-electrode current collector and the first negative-electrode film layer; and the first negative-electrode film layer includes a first negative-electrode active material, the first negative-electrode active material includes a first graphite, the first graphite is artificial graphite, and a distribution of volume-based particle size D v 99 of the first negative-electrode active material is ≤23 μm.
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 layer, the negative-electrode film layer comprising a first negative-electrode film layer and a second negative-electrode film layer, wherein
the second negative-electrode film layer is located between the negative-electrode current collector and the first negative-electrode film layer;
the first negative-electrode film layer comprises a first negative-electrode active material, the first negative-electrode active material comprising a first graphite, the first graphite being artificial graphite, and a distribution of volume-based particle size D v 99 of the first negative-electrode active material is 17 μm≤D v 99≤23 μm; and
the second negative-electrode film layer comprises a second negative-electrode active material comprising a second graphite, and a distribution of volume-based particle size Dv99 of the second negative-electrode active material is greater than the distribution of volume-based particle size Dv99 of the first negative-electrode active material.
2. The secondary battery according to claim 1 , wherein the first negative-electrode active material satisfies 18 μm≤Dv99≤21 μm.
3. The secondary battery according to claim 1 , wherein the first negative-electrode active material satisfies 8 μm≤D v 50≤13 μm.
4. The secondary battery according to claim 1 , wherein a particle size uniformity of the first negative-electrode active material is 0.28-0.4.
5. The secondary battery according to claim 1 , wherein the first graphite comprises secondary particles, a number percentage of the secondary particles in the first graphite is ≥50%.
6. The secondary battery according to claim 1 , wherein a particle size specific surface area of the first negative-electrode active material is 0.45 m 2 /g-0.65 m 2 /g.
7. The secondary battery according to claim 1 , wherein the first negative-electrode active material satisfies: 0.6≤(D v 90-D v 10)/D v 50≤1.8.
8. The secondary battery according to claim 1 , wherein a distribution of volume-based particle size D v 10 of the first negative-electrode active material is 5 μm-9 μm; or
a distribution of volume-based particle size D v 90 of the first negative-electrode active material is 14 μm-21 μm.
9. The secondary battery according to claim 1 , wherein the first negative-electrode active material further satisfies one or more of the following (1) to (5):
(1) a powder OI value of the first negative-electrode active material is 2.0-4.0;
(2) a tap density of the first negative-electrode active material is 0.85 g/cm 3 -1.4 g/cm 3 ;
(3) a powder compacted density of the first negative-electrode active material under a pressure of 2 kN is 1.55 g/cm 3 -1.70 g/cm 3 ;
(4) a specific surface area (SSA) of the first negative-electrode active material is 0.8 m 2 /g-1.3 m 2 /g; and
(5) a gram capacity of the first negative-electrode active material is 345 mAh/g-360 mAh/g.
10. The secondary battery according to claim 1 , wherein at least part of a surface of the first graphite is provided with an amorphous carbon coating layer.
11. The secondary battery according to claim 1 , wherein a mass percentage of the first graphite in the first negative-electrode active material is ≥80%.
12. The secondary battery according to claim 1 , wherein the second graphite comprises one or more of artificial graphite and natural graphite.
13. The secondary battery according to claim 1 , wherein the distribution of volume-based particle size D v 99 of the second negative-electrode active material is 41.6 μm≤Dv99≤52.3 μm.
14. The secondary battery according to claim 1 , wherein a ratio of the distribution of volume-based particle size D v 99 of the second negative-electrode active material to the distribution of volume-based particle size D v 99 of the first negative-electrode active material is 2.0-2.6.
15. The secondary battery according to claim 1 , wherein the second negative-electrode active material further satisfies the following (1) to (5):
(1) a mass percentage of the artificial graphite in the second graphite is ≥50%;
(2) a volume-based median particle size D v 50 of the second negative-electrode active material is 15 μm-21 μm;
(3) a particle size uniformity of the second negative-electrode active material is 0.3-0.55;
(4) the second graphite comprises primary particles, a number percentage of the primary particles in the second graphite is ≥50%;
(5) a particle size specific surface area of the second negative-electrode active material is 0.35 m 2 /g-0.55 m 2 /g.
16. The secondary battery according to claim 12 , wherein the second negative-electrode active material further satisfies the following (1) to (8):
(1) the second negative-electrode active material satisfies: 0.9≤(D v 90-D v 10)/D v 50≤1.6;
(2) a distribution of volume-based particle size D v 10 of the second negative-electrode active material is 5 μm-14 μm;
(3) a distribution of volume-based particle size D v 90 of the second negative-electrode active material is 24 μm-38 μm;
(4) a powder OI value of the second negative-electrode active material is ≤14;
(5) a tap density of the second negative-electrode active material is 0.8 g/cm 3 -1.2 g/cm 3 ;
(6) a powder compacted density of the second negative-electrode active material under a pressure of 2 kN is 1.70 g/cm 3 -1.85 g/cm 3 ;
(7) a specific surface area (SSA) of the second negative-electrode active material is 1.0 m 2 /g-2.0 m 2 /g; and
(8) a gram capacity of the second negative-electrode active material is 353 mAh/g-370 mAh/g.
17. The secondary battery according to claim 1 , wherein the negative-electrode film layer further satisfies the following (1) to (3):
(1) an areal density of the negative-electrode film layer is 0.117 mg/mm 2 -0.130 mg/mm 2 ;
(2) a compacted density of the negative-electrode film layer is 1.65 g/cm 3 -1.75 g/cm 3 ; and
(3) a thickness ratio of the second negative-electrode film layer to the first negative-electrode film layer is 0.7:1-2.3:1.
18. The secondary battery according to claim 12 , wherein the first negative-electrode active material or the second negative-electrode active material further comprises one or more of silicon-based material, tin-based material, soft carbon, hard carbon, and lithium titanate.
19. 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 layer that is disposed on at least one surface of the positive-electrode current collector and that comprises a positive-electrode active material, the positive-electrode active material comprises one or more of lithium transition metal oxide, olivine-structured lithium-containing phosphate, and respective modified compounds thereof.
20. An apparatus, comprising the secondary battery according to claim 1 .