Secondary battery
The present disclosure provides a secondary battery, the secondary battery comprises a positive electrode plate, a negative electrode plate, a separator and an electrolyte, the positive electrode plate comprises a positive current collector and a positive film, the positive film is provided on at least one surface of the positive current collector and comprises a positive active material, the negative electrode plate comprises a negative current collector and a negative film, the negative film is provided on at least one surface of the negative current collector and comprises a negative active material, the negative active material comprises graphite, and an average particle diameter of the positive active material represented by D50 and a thickness of the negative film represented by H n satisfy a relationship: 6≤0.06H n ×(4−1/D50)≤31. The battery of the present disclosure has the characteristics of excellent dynamics performance and long cycle life at the same time.
1. A secondary 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 negative active material comprises graphite, and an average particle diameter of the positive active material represented by D50 and a thickness of the negative film represented by H n satisfy a relationship: 8≤0.06H n ×(4−1/D50)≤20;
a unit of the average particle diameter of the positive active material represented by D50 is μm, a unit of the thickness of the negative film represented by H n is μm; and
a pressing density of the negative film represented by PD and an OI value of the negative film represented by V OI satisfy a relationship: 0.3≤(PD+0.13×V OI )/9.2≤0.63, and a unit of the pressing density of the negative film represented by PD is g/cm 3 ; and
the pressing density of the negative film represented by PD is 0.8 g/cm 3 ≤PD≤1.25 g/cm 3 .
2. The secondary battery according to claim 1 , wherein the average particle diameter of the positive active material represented by D50 is 0.5 μm-15 μm.
3. The secondary battery according to claim 2 , wherein the average particle diameter of the positive active material represented by D50 is 3 μm-9 μm.
4. The secondary battery according to claim 1 , wherein the OI value of the negative film represented by V OI is 1-150.
5. The secondary battery according to claim 4 , wherein the OI value of the negative film represented by V OI is 8-70.
6. The secondary battery according to claim 1 , wherein an OI value of a powder of the negative active material represented by G OI is 0.5-7.
7. The secondary battery according to claim 6 , wherein the OI value of the powder of the negative active material represented by G OI is 2-4.5.
8. The secondary 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.
9. The secondary battery according to claim 1 , wherein the thickness of the negative film represented by H n is 25 μm-42 μm.