Lithium ion secondary battery

1. A lithium ion secondary battery comprising a positive electrode plate, a negative electrode plate, a separator and an electrolyte, wherein

the positive electrode plate comprises a positive electrode current collector and a positive electrode film provided on at least one surface of the positive electrode current collector, and the positive electrode film comprises a first positive electrode active material represented by chemical formula (1) and a second positive electrode active material represented by chemical formula (2),

Li 1+x Ni a Co b Me 1-a-b O 2-y A y   chemical formula (1)

Li 1+z Mn c N 2-c O 4-d B d   chemical formula (2)

in the chemical formula (1), −0.1≤x≤0.2, 0<a<1, 0<b<1, 0<a+b<1, 0≤y<0.2, Me comprises one or more of Mn, Fe, Cr, Ti, Zn, V, Al, Zr and Ce, and A comprises one or more of S, N, F, Cl, Br and I,

in the chemical formula (2), −0.1≤z≤0.2, 0<c≤2, 0≤d<1, N comprises one or more of Ni, Fe, Cr, Ti, Zn, V, Al, Mg, Zr and Ce, and B comprises one or more of S, N, F, Cl, Br and I;

the positive electrode plate has a resistivity r of 3500 Ω·m or less; and,

the electrolyte comprises a fluorine-containing lithium salt type additive;

wherein the positive electrode plate and the electrolyte in the lithium ion secondary battery satisfy the following formula (11)

0

.

0

⁢

0

⁢

5

≤

u

1

⁢

0

⁢

0

⁢

v

≤

2

⁢

7

.

5

formula

⁢

(

11

)

in which v is weight of manganese element contained in the positive electrode film per unit area, in g/cm 2 ; and u is weight percentage of fluorine-containing lithium salt type additive in the electrolyte, in wt %, and

wherein the positive electrode plate and the electrolyte in the lithium ion secondary battery satisfy the following formula (21),

−1.2≤ln r−s 1 ≤2  formula (21)

in which, r is resistivity of the positive electrode plate in Ω·m; and s 1 is ionic conductivity of the electrolyte at 25° C. in mS/cm.

2. The lithium ion secondary battery according to claim 1 , wherein the positive electrode plate and the electrolyte in the lithium ion secondary battery satisfy the following formula (22),

−0.5≤ln r−s 1 ≤1.5  formula (22).

3. The lithium ion secondary battery according to claim 1 , wherein the resistivity of the positive electrode plate is 2500 Ω·m or less.

4. The lithium ion secondary battery according to claim 1 , wherein the resistivity of the positive electrode plate is 1200 Ω·m or less.

5. The lithium ion secondary battery according to claim 1 , wherein in the chemical formula (1), 0.5≤a<1, 0<b<0.5, 0.7≤a+b<1, 0≤y<0.1, M is one or both of Mn and Al, and A is one or both of S and F.

6. The lithium ion secondary battery according to claim 1 , wherein the fluorine-containing lithium salt type additive is one or more of a compound represented by chemical formula (3) and a compound represented by chemical formula (4),

in the chemical formula (3), R is one or more of F, Cl, Br, and I, and R comprises F, M is P or B, when M is P, n+2m=6, and m is 1 or 2, and when M is B, n+2m=4, and m is 0 or 1,

in the chemical formula (4), G is one or more of F, Cl, Br and I, and G comprises F, E is P or B, when E is P, x+2y=6, and y is 1 or 2, and when E is B, x+2y=4, and y is 0 or 1.

7. The lithium ion secondary battery according to claim 6 , wherein the fluorine-containing lithium salt type additive is one or more of lithium difluorophosphate LiPO 2 F 2 , lithium difluorooxalate phosphate LiDFOP, lithium tetrafluoroborate LiBF 4 , and lithium difluorooxalate borate LiDFOB.

8. The lithium ion secondary battery according to claim 1 , wherein the fluorine-containing lithium salt type additive is present in the electrolyte in a weight percentage u of 0.005 wt %-3 wt %.

9. The lithium ion secondary battery according to claim 1 , wherein the fluorine-containing lithium salt type additive is present in the electrolyte in a weight percentage u of 0.1 wt %-2 wt %.

10. The lithium ion secondary battery according to claim 1 , wherein the positive electrode film comprises manganese element in a weight v of 1.1×10 −3 g/cm 2 −9.1×10 −3 g/cm 2 per unit area.

11. The lithium ion secondary battery according to claim 1 , wherein the positive electrode film comprises manganese element in a weight v of 1.1×10 −3 g/cm 2 −8.2×10 −3 g/cm 2 per unit area.

12. The lithium ion secondary battery according to claim 1 , wherein the positive electrode plate and the electrolyte in the lithium ion secondary battery satisfy the following formula (12)

0

.

0

⁢

1

≤

u

1

⁢

0

⁢

0

⁢

v

≤

2

⁢

0

.

0

formula

⁢

(

12

)

in which v is weight of manganese element contained in the positive electrode film per unit area, in g/cm 2 ; and u is weight percentage of fluorine-containing lithium salt type additive in the electrolyte, in wt %.

13. The lithium ion secondary battery according to claim 1 , wherein the electrolyte further contains a negative electrode film-forming enhancer; and

the negative electrode film-forming enhancer is one or more of cyclic carbonates with unsaturated bonds in side chains, fluorine-containing cyclic carbonates and cyclic sulfonates.

14. The lithium ion secondary battery according to claim 13 , wherein the negative electrode film-forming enhancer is one or more of vinyl ethylene carbonate VEC, methylene methanedisulfonate MMDS, difluoroethylene carbonate DFEC, trifluoromethyl ethylene carbonate TFPC, and 1-propene-1,3-sultone PST.

15. The lithium ion secondary battery according to claim 13 , wherein the negative electrode film-forming enhancer is present in the electrolyte in a weight percentage of 0.005 wt %-6 wt %.

16. The lithium ion secondary battery according to claim 13 , wherein the negative electrode film-forming enhancer is present in the electrolyte in a weight percentage of 0.01 wt %-5 wt %.

17. The lithium ion secondary battery according to claim 13 , wherein the negative electrode film-forming enhancer is present in the electrolyte in a weight percentage of 0.1 wt %-2 wt %.