Method for supplementing lithium for secondary battery and method for charging and discharging secondary battery
A method for supplementing lithium for a secondary battery includes performing a first round of lithium-supplementing charge and discharge on the secondary battery during routine charge-and-discharge cycles of the secondary battery if a capacity of the secondary battery has reduced by k1 in comparison with an initial capacity and performing a round of lithium-supplementing charge and discharge on the secondary battery after the first round of lithium-supplementing charge and discharge if the capacity of the secondary battery has reduced by k2 in comparison with the capacity achieved after a previous round of lithium-supplementing charge and discharge. k1 and k2 each are in a range from 1.5% to 17%. In a round of lithium-spplementing charge and discharge, a number of times of charge and discharge is at least one and a charge cut-off voltage is in a range from 4.45 V to 5 V.
1 . A method for supplementing lithium for a secondary battery, comprising:
performing a first round of lithium-supplementing charge and discharge on the secondary battery during routine charge-and-discharge cycles of the secondary battery in response to a capacity of the secondary battery having reduced by k1 in comparison with an initial capacity; and
performing a round of lithium-supplementing charge and discharge on the secondary battery after the first round of lithium-supplementing charge and discharge in response to the capacity of the secondary battery having reduced by k2 in comparison with the capacity achieved after a previous round of lithium-supplementing charge and discharge;
wherein:
k1 and k2 each are in a range from 1.5% to 17%;
in each round of lithium-supplementing charge and discharge, a number of times of charge and discharge is at least one and a charge cut-off voltage is in a range from 4.45 V to 5 V; and
a positive electrode plate of the secondary battery comprises a lithium supplement material, and the lithium supplement material is at least one selected from Li 2 O, Li 2 O 2 , Li 2 S, Li 6 CoO 4 , Li 5 FeO 4 , Li 2 NiO 2 , Li 2 DHBN, Li 2 C 2 O 4 , and xLi 2 MnO 3 ·(1−x)LiNi y1 Co y2 Mn y3 O 2 , wherein 0<x≤1, y1, y2, and y3 each are in a range from 0 to 1, and a sum of y1, y2, and y3 is 1.
2 . The method for supplementing lithium according to claim 1 , wherein the charge cut-off voltage is in a range from 4.45 V to 4.6 V.
3 . The method for supplementing lithium according to claim 1 , wherein k1 and k2 each are in a range from 2% to 15%.
4 . The method for supplementing lithium according to claim 3 , wherein k1 and k2 each are in a range from 2% to 12%.
5 . The method for supplementing lithium according to claim 1 , wherein a discharge cut-off voltage applied in the lithium-supplementing charge and discharge is a discharge cut-off voltage applied in a routine charge-and-discharge cycle.
6 . The method for supplementing lithium according to claim 1 , wherein the lithium-supplementing charge and discharge adopt constant-current charge.
7 . The method for supplementing lithium according to claim 1 , wherein a charge current applied in the lithium-supplementing charge and discharge is a charge current applied in a routine charge-and-discharge cycle.
8 . The method for supplementing lithium according to claim 1 , wherein the lithium-supplementing charge and discharge adopt constant-current discharge.
9 . The method for supplementing lithium according to claim 1 , wherein a discharge current applied in the lithium-supplementing charge and discharge is a discharge current applied in a routine charge-and-discharge cycle.
10 . The method for supplementing lithium according to claim 1 , wherein, during the lithium-supplementing charge and discharge, charging is performed first, and then discharging is performed after a period of static standing.
11 . The method for supplementing lithium according to claim 10 , wherein the period of static standing is in a range from 2 to 35 minutes.
12 . The method for supplementing lithium according to claim 11 , wherein the period of static standing is in a range from 5 to 30 minutes.
13 . The method for supplementing lithium according to claim 1 , wherein the lithium supplement material comprises 0.4LiNi 0.5 Co 0.1 Mn 0.4 O 2 ·0.6Li 2 MnO 3 .
14 . The method for supplementing lithium according to claim 1 , wherein, in the positive electrode plate, a mass ratio between a positive active material and the lithium supplement material is in a range from 1:8 to 8:1.
15 . The method for supplementing lithium according to claim 1 , wherein the mass ratio between the positive active material and the lithium supplement material is in a range from 2:8 to 7:3.
16 . A method for charging and discharging a secondary battery, comprising:
supplementing lithium for the secondary battery, comprising:
performing a first round of lithium-supplementing charge and discharge on the secondary battery during routine charge-and-discharge cycles of the secondary battery in response to a capacity of the secondary battery having reduced by k1 in comparison with an initial capacity; and
performing a round of lithium-supplementing charge and discharge on the secondary battery after the first round of lithium-supplementing charge and discharge in response to the capacity of the secondary battery having reduced by k2 in comparison with the capacity achieved after a previous round of lithium-supplementing charge and discharge;
wherein:
k1 and k2 each are in a range from 1.5% to 17%;
in each round of lithium-supplementing charge and discharge, a number of times of charge and discharge is at least one and a charge cut-off voltage is in a range from 4.45 V to 5 V; and
a positive electrode plate of the secondary battery comprises a lithium supplement material, and the lithium supplement material is at least one selected from Li 2 O, Li 2 O 2 , Li 2 S, Li 6 CoO 4 , Li 5 FeO 4 , Li 2 DHBN, Li 2 C 2 O 4 , and xLi 2 MnO 3 ·(1−x)LiNi y1 Co y2 Mn y3 O 2 , wherein 0<x≤1, y1, y2, and y3 each are in a range from 0 to 1, and a sum of y1, y2, and y3 is 1; and
continuing to perform the routine charge-and-discharge cycles on the secondary battery after the lithium supplementing until an end of life of the secondary battery.