US 11,929,492 B2
Lithium-ion secondary battery and related preparation method thereof, battery module, battery pack and apparatus
Zhiqiang Li, Ningde (CN); Qifeng Li, Ningde (CN); and Changlong Han, Ningde (CN)
Assigned to Contemporary Amperex Technology Co., Limited, Ningde (CN)
Filed by Contemporary Amperex Technology Co., Limited, Ningde (CN)
Filed on Dec. 31, 2021, as Appl. No. 17/566,698.
Application 17/566,698 is a continuation of application No. PCT/CN2020/099734, filed on Jul. 1, 2020.
Claims priority of application No. 201910618721.1 (CN), filed on Jul. 10, 2019.
Prior Publication US 2022/0123286 A1, Apr. 21, 2022
Int. Cl. H01M 4/36 (2006.01); H01M 4/04 (2006.01); H01M 4/505 (2010.01); H01M 4/525 (2010.01); H01M 4/02 (2006.01)
CPC H01M 4/366 (2013.01) [H01M 4/0404 (2013.01); H01M 4/505 (2013.01); H01M 4/525 (2013.01); H01M 2004/021 (2013.01); H01M 2004/028 (2013.01); H01M 2220/20 (2013.01)] 15 Claims
 
1. A lithium-ion secondary battery, comprising a positive electrode plate, a negative electrode plate, an electrolyte and a separator, wherein the positive electrode plate comprises a positive electrode current collector and a first positive electrode active material layer and a second positive electrode active material layer sequentially disposed on at least one side of the positive electrode current collector; the lithium-ion secondary battery satisfies formula (I):
0.05≤log10(u/v)×w≤15.5  formula(I)
wherein,
u is a thickness of the first positive electrode active material layer in microns,
v is a thickness of the second positive electrode active material layer in microns,
w is a conductivity of the electrolyte at a temperature of 25° C. in mS·cm−1,
wherein the first positive electrode active material layer comprises a first positive electrode active material being the compound of formula (II),
Li1+xNiaCobM1-a-bO2-yAy  formula (II)
wherein, −0.1≤x≤0.2, 0.7≤a<1, 0 b<1, 0<a+b<1, 0≤y<0.2, M is one or more of Mn, Fe, Cr, Ti, Zn, V, Al, Zr and Ce, and A is one or more of S, F, Cl and I, and
the second positive electrode active material layer comprises a second positive electrode active material, and the second positive electrode active material is one or more of lithium manganate, lithium iron phosphate, lithium vanadate and lithium nickel manganese oxide and wherein ratio of the thickness u of the first positive electrode active material to the thickness v of the second positive electrode active material is u/v≥5.