Lithium-ion battery

1. A lithium-ion battery comprising a positive electrode plate, a negative electrode plate, a separator and an electrolyte, the positive electrode plate comprising a positive current collector and a positive film, the positive film being provided on at least one surface of the positive current collector and comprising a positive active material, the negative electrode plate comprising a negative current collector and a negative film, the negative film being provided on at least one surface of the negative current collector and comprising a negative active material;

wherein

the positive active material comprises a material with a chemical formula of Li a Ni x Co y M 1-x-y O 2 , M is one or two selected from Al and Mn, 0.95≤a≤1.2, 0<x<1, 0<y<1, 0<x+y<1;

the negative active material comprises graphite;

an OI value of the positive film represented by OI c and an OI value of the negative film represented by OI a satisfy a relationship: 0.05≤OI a /OI c ≤10;

OI c =C 003 /C 110 , C 003 represents characteristic diffraction peak area of (003) crystal plane in X-ray diffraction pattern of the positive film, C 110 represents characteristic diffraction peak area of (110) crystal plane in X-ray diffraction pattern of the positive film;

OI a =C 004 /C 110 , C 004 represents characteristic diffraction peak area of (004) crystal plane in X-ray diffraction pattern of the negative film, C 110 represents characteristic diffraction peak area of (110) crystal plane in X-ray diffraction pattern of the negative film; and

the OI value of the positive film represented by OI c is 5˜80.

2. The lithium-ion battery according to claim 1 , wherein the OI value of the positive film represented by OI c and the OI value of the negative film represented by OI a satisfy a relationship: 0.2≤OI a /OI c ≤3.

3. The lithium-ion battery according to claim 1 , wherein

the OI value of the negative film represented by OI a is 5˜30.

4. The lithium-ion battery according to claim 1 , wherein

an average particle diameter D50 of the positive active material is 3 μm˜12 μm;

an average particle diameter D50 of the negative active material is 4 μm˜15 μm.

5. The lithium-ion battery according to claim 1 , wherein

an OI value of a powder of the positive active material represented by G OI is 3˜15;

an OI value of a powder of the negative active material represented by V OI is 2˜15;

G OI =C′ 003 /C′ 110 , C′ 003 represents characteristic diffraction peak area of (003) crystal plane in X-ray diffraction pattern of the powder of the positive active material, C′ 110 represents characteristic diffraction peak area of (110) crystal plane in X-ray diffraction pattern of the powder of the positive active material; and

V OI =C′ 004 /C′ 110 , C′ 004 represents characteristic diffraction peak area of (004) crystal plane in X-ray diffraction pattern of the powder of the negative active material, C′ 110 represents characteristic diffraction peak area of (110) crystal plane in X-ray diffraction pattern of the powder of the negative active material.

6. The lithium-ion battery according to claim 5 , wherein

the OI value of a powder of the positive active material represented by G OI is 5˜10;

the OI value of a powder of the negative active material represented by V OI is 2˜11.

7. The lithium-ion battery according to claim 1 , wherein

the pressing density of the positive film is 3.0 g/cm 3 ˜3.5 g/cm 3 ;

the pressing density of the negative film is 1.0 g/cm 3 ˜1.6 g/cm 3 .

8. The lithium-ion battery according to claim 1 , wherein the positive active material further comprises one or more selected from a group consisting of layered LiMnO 2 , spinel LiMn 2 O 4 , LiNi x Mn 2-x O 4 , LiCoO 2 and LiFePO 4 , 0<x<2.

9. The lithium-ion battery according to claim 1 , wherein

doping modification and/or coating modification is further performed on the positive active material.

10. The lithium-ion battery according to claim 1 , wherein the negative active material further comprises one or more selected from a group consisting of soft carbon, hard carbon, carbon fiber, mesocarbon microbeads, silicon-based material, tin-based material and lithium titanate.

11. The lithium-ion battery according to claim 2 , wherein the OI value of the positive film represented by OI c and the OI value of the negative film represented by OI a satisfy a relationship: 0.2≤OI a /OI c ≤0.60.

12. The lithium-ion battery according to claim 3 , wherein the OI value of the positive film represented by OI c is 10˜80.

13. The lithium-ion battery according to claim 12 , wherein the OI value of the positive film represented by OI c is 15˜80.

14. The lithium-ion battery according to claim 13 , wherein the OI value of the positive film represented by OI c is 28˜50.

15. The lithium-ion battery according to claim 3 , wherein the OI value of the negative film represented by OI a is 12˜30.

16. The lithium-ion battery according to claim 15 , wherein the OI value of the negative film represented by OI a is 15˜30.

17. The lithium-ion battery according to claim 4 , wherein

the average particle diameter D50 of the positive active material is 3 μm˜7.8 μm;

and/or, the average particle diameter D50 of the negative active material is 4 μm˜12 μm.

18. The lithium-ion battery according to claim 7 , wherein

the pressing density of the positive film is 3.3 g/cm 3 ˜3.5 g/cm 3 ;

and/or, the pressing density of the negative film is 1.40 g/cm 3 ˜1.6 g/cm 3 .

19. The lithium-ion battery according to claim 1 , wherein the positive active material comprises one or more selected from a group consisting of LiNi 0.5 Co 0.2 Mn 0.3 O 2 , LiNi 0.6 Co 0.2 Mn 0.2 O 2 , LiNi 0.8 Co 0.1 Mn 0.1 O 2 , LiNi 0.8 Co 0.1 Al 0.1 O 2 and LiNi 0.85 Co 0.15 Al 0.05 O 2 .

20. The lithium-ion battery according to claim 1 , wherein at least a part of the positive active material is monocrystal particles.