US 12,218,311 B2
Secondary battery, battery module, battery pack, and electrical device
Quanguo Li, Ningde (CN); Yonghuang Ye, Ningde (CN); Qian Liu, Ningde (CN); Jianfu He, Ningde (CN); Fajun Huang, Ningde (CN); and Chenhui Lin, Ningde (CN)
Assigned to CONTEMPORARY AMPEREX TECHNOLOGY (HONG KONG) LIMITED, Hong Kong (CN)
Filed by CONTEMPORARY AMPEREX TECHNOLOGY (HONG KONG) LIMITED, Hong Kong (CN)
Filed on Aug. 7, 2023, as Appl. No. 18/366,342.
Application 18/366,342 is a continuation of application No. PCT/CN2021/127721, filed on Oct. 29, 2021.
Prior Publication US 2023/0378546 A1, Nov. 23, 2023
Int. Cl. H01M 10/0585 (2010.01); H01M 4/38 (2006.01); H01M 4/505 (2010.01); H01M 4/525 (2010.01); H01M 4/58 (2010.01); H01M 4/583 (2010.01); H01M 4/62 (2006.01); H01M 4/02 (2006.01)
CPC H01M 10/0585 (2013.01) [H01M 4/381 (2013.01); H01M 4/505 (2013.01); H01M 4/525 (2013.01); H01M 4/5825 (2013.01); H01M 4/583 (2013.01); H01M 4/622 (2013.01); H01M 4/623 (2013.01); H01M 4/625 (2013.01); H01M 2004/021 (2013.01); H01M 2004/027 (2013.01); H01M 2004/028 (2013.01); H01M 2220/20 (2013.01)] 12 Claims
 
1. A secondary battery, wherein the secondary battery comprises a positive electrode plate, a negative electrode plate, and a separator between the positive electrode plate and the negative electrode plate:
wherein the positive electrode plate comprises a positive current collector, a first positive active material layer distributed on one side of the positive current collector and a second positive active material layer distributed on another side of the positive current collector;
wherein the negative electrode plate comprises a negative current collector, a first negative active material layer distributed on one side of the negative current collector and opposite to the second positive active material layer and a second negative active material layer distributed on another side of the negative current collector;
a coating weight of a positive active material per unit area of the first positive active material layer is CW1 and a coating weight of the positive active material per unit area of the second positive active material layer is CW2;
wherein 6.5 mg/cm2≤CW1≤32.5 mg/cm2, 6.5 mg/cm2≤CW2≤32.5 mg/cm2 and 0.5≤CW1/CW2<1;
wherein the first negative active material layer and the second negative active material layer are different in composition and
wherein, a resistance of the first positive active material layer is R1, a resistance of the second positive active material layer is R2, a resistance of the first negative active material layer is R3, a resistance of the second negative active material layer is R4, and the resistances R1, R2, R3, and R4 are Ohmic resistances and satisfy the following relationships:
R2>R1;  (1)
R3≥R4;  (2)
0<(R1+R4)/(R2+R3)≤1; and  (3)
R1/R2=A×R4/R3, wherein A is 0.8 to 1.2,  (4)
wherein R1 is 0.1Ω to 20Ω, R2 is 0.15Ω to 22Ω, R3 is 0.7 mΩ to 40 mΩ, and
R4 is 0.5 mΩ to 35 mΩ.