CPC H01M 10/0567 (2013.01) [H01M 10/0525 (2013.01); H01M 10/0568 (2013.01); H01M 50/534 (2021.01); H01M 2220/20 (2013.01)] | 19 Claims |
1. A secondary battery, comprising an electrode assembly and an electrolytic solution, the electrode assembly comprising a positive electrode plate, a negative electrode plate, and a separator, the positive electrode plate comprising a positive electrode tab, and the negative electrode plate comprising a negative electrode tab, wherein the positive electrode tab has a following temperature rise coefficient α A.h/mm:
where S1 is a total cross-sectional area of the positive electrode tab, in unit of mm2; C is capacity of the electrode assembly, in unit of Ah, wherein α is from 2 to 9.5;
the electrolytic solution contains a heat stable salt and an additive that inhibits decomposition of lithium salt, wherein
the heat stable salt has a following molecular formula:
(My+)x/yR1(SO2N)xSO2R2,
wherein
My+ is one or more selected from the group consisting of Li+, Na+, K+, Rb+, Cs+, Mg2+, Ca2+, Ba2+, Al3+, Fe2+, Fe3+, Ni2+, and Ni3+, optionally, My+ is one or more selected from the group consisting of Li+, K+, Cs+, and Ba2+, and y is valence of the M,
the R1 and R2 are each independently selected from the group consisting of fluorine atom, fluoroalkyl having 1˜20 carbon atoms, fluoroalkoxy having 1˜20 carbon atoms, and alkyl having 1˜20 carbon atoms,
x is an integer selected from the group consisting of 1, 2, and 3,
by mass percentage, a content of the heat stable salt in the electrolytic solution is w %, wherein w % is from 8% to 30%,
the additive that inhibits decomposition of lithium salt is one or more of RSO3F, where R is one or more selected from the group consisting of Li+, Na+, K+, Rb+, and Cs+,
by mass percentage, a content of the additive that inhibits decomposition of lithium salt in the electrolytic solution is m1%, wherein m1% is from 0.1% to 5%, and
w, m1, and α satisfy 0.5<m1w/α<20.
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