Negative electrode plate and secondary battery

Abstract

The present application relates to a negative electrode plate and a secondary battery. Specifically, the present application provides a negative electrode plate comprising a negative electrode current collector and an negative electrode film coated on at least one surface of the negative electrode current collector and containing the negative active material, wherein the negative electrode plate satisfies 0.6 0.7×P×(D90-D10)/D5O+B/3 8.0 wherein P refers to the porosity of the negative electrode film; B refers to the active specific surface area of the negative electrode film, and the unit thereof is m 2 /g; D10 refers to the particle size corresponding to the cumulative volume percentage of the negative active material reaching 10%, D90 refers to the particle size corresponding to the cumulative volume percentage of the negative active material reaching 90%, and D50 refers to the particle size corresponding to the cumulative volume percentage of the negative active material reaching 50%.

1 . A negative electrode plate comprising a negative electrode current collector and a negative electrode film coated on at least one surface of the negative electrode current collector and containing a negative active material, wherein the negative electrode plate satisfies the following Formula I:
   0.6 0.7 ×P ×( D 90− D 10)/ D 50+ B/ 3   Formula I)
   wherein,   P refers to the porosity of the negative electrode film;   B refers to the active specific surface area of the negative electrode film, and the unit thereof is m 2 /g;   D10 refers to the particle size corresponding to the cumulative volume percentage of the negative active material reaching 10%; D90 refers to the particle size corresponding to the cumulative volume percentage of the negative active material reaching 90%, and D50 refers to the particle size corresponding to the cumulative volume percentage of the negative active material reaching 50%, i.e. the median particle size of the volume distribution, the units of D10, D90, and D50 are all μm.   
     
     
         2 . The negative electrode plate according to  claim 1 , wherein the negative electrode plate satisfies the following Formula II:
   1.2 0.7 ×P ×( D 90 −D 10)/ D 50+ B/ 3 4.0   Formula II).
   
     
     
         3 . The negative electrode plate according to  claim 1 , wherein the porosity P of the negative electrode film satisfies 20% P 60%. 
     
     
         4 . The negative electrode plate according to  claim 3 , wherein the porosity P of the negative electrode film satisfies 25% P 45%. 
     
     
         5 . The negative electrode plate according to  claim 1 , wherein the active specific surface area B of the negative electrode film satisfies 1 m 2 /g B 15 m 2 /g. 
     
     
         6 . The negative electrode plate according to  claim 5 , wherein the active specific surface area B of the negative electrode film satisfies 4 m 2 /g B 10 m 2 /g. 
     
     
         7 . The negative electrode plate according to  claim 1 , wherein the negative active material satisfies: 10 μm D90 60 μm; and/or
 4 μm D50 20 μm; and/or 
 1 μm D10 15 μm. 
 
     
     
         8 . The negative electrode plate according to  claim 7 , wherein the negative active material satisfies: 15 μm D90 40 μm; and/or
 5 μm D50 14 μm; and/or 
 3 μm D10 10 μm. 
 
     
     
         9 . The negative electrode plate according to  claim 1 , wherein the negative active material satisfies 0.3 (D90−D10)/D50 8. 
     
     
         10 . The negative electrode plate according to  claim 9 , wherein the negative active material satisfies 0.8 (D90−D10)/D50 3. 
     
     
         11 . The negative electrode plate according to  claim 1 , characterized in that the packed density PD of the negative electrode film satisfies 0.8 g/cm 3   PD 2.0 g/cm 3 . 
     
     
         12 . The negative electrode plate according to  claim 11 , characterized in that the packed density PD of the negative electrode film satisfies 1.0 g/cm 3   PD 1.8 g/cm 3 . 
     
     
         13 . The negative electrode plate according to  claim 1 , wherein the coating weight CW per unit area of the negative electrode film satisfies 2 mg/cm 2   CW 13 mg/cm 2 . 
     
     
         14 . The negative electrode plate according to  claim 13 , wherein the coating weight CW per unit area of the negative electrode film satisfies 5 mg/cm 2   CW 10 mg/cm 2 . 
     
     
         15 . The negative electrode plate of  claim 1 , wherein the negative active material is selected from one or more of graphite material, soft carbon, hard carbon, carbon fibers, mesocarbon microbreads, silicon-based material, tin-based material, and lithium titanium oxide. 
     
     
         16 . A secondary battery comprising the negative electrode plate according to  claim 1 .