Secondary battery and apparatus containing such secondary battery

1. A secondary battery, comprising a negative electrode plate, wherein the negative electrode plate comprises a copper-based current collector and a negative electrode film layer disposed on at least one surface of the copper-based current collector, the negative electrode film layer comprising a negative electrode active material and the negative electrode active material comprising graphite,

wherein the negative electrode plate satisfies T x ≥25, and

T x =√{square root over ( I Cu 2 /( I 004 ×I 110 ))}, wherein

I Cu represents a diffraction peak intensity of a (111) crystal plane of the copper-based current collector of the negative electrode plate in an X-ray diffraction pattern;

I 110 represents a diffraction peak intensity of a (110) crystal plane of the graphite of the negative electrode plate in the X-ray diffraction pattern; and

I 004 represents a diffraction peak intensity of a (004) crystal plane of the graphite of the negative electrode plate in the X-ray diffraction pattern.

2. The secondary battery according to claim 1 , wherein the negative electrode plate satisfies 29≤T x ≤70.

3. The secondary battery according to claim 1 , wherein the negative electrode plate satisfies 35≤T x ≤60.

4. The secondary battery according to claim 1 , wherein the negative electrode plate satisfies 40≤T x ≤50.

5. The secondary battery according to claim 1 , wherein thickness of the copper-based current collector is less than or equal to 8 μm, and the thickness of the copper-based current collector is 4 μm to 6.5 μm.

6. The secondary battery according to claim 1 , wherein a mass percentage of Cu in the copper-based current collector is greater than or equal to 99%, and the mass percentage of Cu in the copper-based current collector is 99.5% to 100%.

7. The secondary battery according to claim 1 , wherein the negative electrode active material satisfies one or more of the following conditions:

(1) a tap density of the negative electrode active material is 0.9 g/cm 3 to 1.15 g/cm 3 , and the tap density of the negative electrode active material is 0.9 g/cm 3 to 1.05 g/cm 3 ;

(2) a volume-based median particle size D v 50 of the negative electrode active material is 6 μm to 14 μm, and the volume-based median particle size D v 50 of the negative electrode active material is 8 μm to 12 μm; and

(3) a gram capacity of the negative electrode active material is 345 mAh/g to 360 mAh/g, and the gram capacity of the negative electrode active material is 348 mAh/g to 355 mAh/g.

8. The secondary battery according to claim 1 , wherein the negative electrode active material comprises artificial graphite; and optionally, a mass percentage of the artificial graphite in the negative electrode active material is greater than or equal to 60%; and optionally, the mass percentage of the artificial graphite in the negative electrode active material is 80% to 100%.

9. The secondary battery according to claim 1 , wherein the negative electrode film layer satisfies one or more of the following conditions (1) and (2):

(1) a compacted density of the negative electrode film layer is 1.4 g/cm 3 to 1.65 g/cm 3 ; and optionally, the compacted density of the negative electrode film layer is 1.45 g/cm 3 to 1.55 g/cm 3 ; and

(2) a surface density of the negative electrode film layer is less than or equal to 12.5 mg/cm 2 ; and optionally, the surface density of the negative electrode film layer is 9.0 mg/cm 2 to 10.5 mg/cm 2 .

10. An apparatus, comprising the secondary battery of claim 1 .