SECONDARY BATTERY, BATTERY MODULE, BATTERY PACK AND ELECTRICAL DEVICE
The present application provides a secondary battery, a battery module, a battery pack, and an electrical device. The secondary battery includes a positive electrode plate, a negative electrode plate comprising a negative electrode active material; and an electrolytic solution including a first additive and a carbonate solvent, and the first additive including a boron-containing lithium salt and an ester additive, which are configured to form a solid electrolyte interface film on the surface of the negative electrode active material, wherein a discharge capacity of the secondary battery is denoted as B1 in Ah, a change in amount of gas production of the secondary battery is denoted as B2 in mL, a mass of the electrolytic solution is denoted as C in g, a reduction potential of the first additive relative to lithium metal is denoted as D.
1 . A secondary battery, comprising
a positive electrode plate,
a negative electrode plate comprising a negative electrode active material; and
an electrolytic solution comprising a first additive and a carbonate solvent, and the first additive comprising a boron-containing lithium salt and an ester additive, which are configured to form a solid electrolyte interface film on the surface of the negative electrode active material,
wherein
a discharge capacity of the secondary battery is denoted as B1 in Ah,
a change in amount of gas production of the secondary battery is denoted as B2 in mL,
a mass of the electrolytic solution is denoted as C in g,
a reduction potential of the first additive relative to lithium metal is denoted as D (V, vs Li + |Li),
a mass percentage of the boron-containing lithium salt relative to a total mass of the electrolytic solution is denoted as A1%; a mass percentage of the ester additive relative to the total mass of the electrolytic solution is denoted as A2, and
the secondary battery satisfies: 0.5≤B2/B1≤5; 0.1≤C/B1≤100; 0.8≤D≤2; 10 −4 ≤A1+A2≤10.
2 . The secondary battery as claimed in claim 1 , wherein the secondary battery satisfies at least one of conditions (1) through (4):
1
≤
B
2
/
B
1
≤
5
;
(
1
)
1
≤
C
/
B
1
≤
5
;
(
2
)
0.85
≤
D
≤
2
;
(
3
)
3
≤
A
1
+
A
2
≤
10.
(
4
)
3 . The secondary battery as claimed in claim 1 , wherein a reduction potential of the boron-containing lithium salt with respect to lithium metal, denoted as D1 (V, vs Li + |Li), satisfies 0.85≤D1≤2; optionally, 0.85≤D1≤1.8; and/or
a reduction potential of the ester additive with respect to lithium metal, denoted as D2 (V, vs Li + |Li), satisfies 0.85≤D2≤2; optionally, 0.85≤D2≤1.2.
4 . The secondary battery as claimed in claim 1 , wherein the boron-containing lithium salt has a molecular formula of LiBF a O b C c P d , in which 0≤a≤4, 0≤b≤8, 0≤c≤4, 0≤d≤4.
5 . The secondary battery as claimed in claim 4 , wherein the boron-containing lithium salt includes one or more of lithium tetrafluoroborate LiBF 4 , lithium bisoxalate borate LiBOB, and lithium bifluorooxalate borate LiDFOB.
6 . The secondary battery as claimed in claim 1 , wherein the electrolytic solution further comprises an ion-conducting lithium salt, and the ion-conducting lithium salt comprises one or more of lithium hexafluorophosphate LiPF 6 , lithium difluorophosphate LiPO 2 F 2 , lithium difluorobisoxalate phosphate LiDODFP, lithium tetrafluorooxalate phosphate LiDFBP, lithium bisfluorosulfonylimide LiFSI, lithium bis(trifluoromethylsulfonyl) imide LiTFSI, lithium fluorosulfonate LiFSO 3 , lithium bis(trifluoromethylsulfonyl) imide LiTFSI, lithium nitrate LiNO 3 , lithium perchlorate LiClO 4 , lithium hexafluoroantimonate LiSbF 6 , and lithium hexafluoroarsenate LiAsF 6 .
7 . The secondary battery as claimed in claim 6 , wherein
based on the total mass of the electrolytic solution, a mass percentage of the ion-conducting lithium salt is denoted as A3%, and
the secondary battery satisfies: 5≤A3≤25; optionally, 10≤A3≤20.
8 . The secondary battery as claimed in claim 1 , wherein the carbonate solvent comprises:
a cyclic carbonate solvent, a mass percentage of which relative to the total mass of the electrolytic solution is denoted as A4%;
a linear carbonate solvent, a mass percentage of which relative to the total mass of the electrolyte is denoted as A5%, and
the secondary battery satisfies: 1≤A5/A4≤10; optionally, 5≤A4≤50; and/or 50≤A5≤70.
9 . The secondary battery as claimed in claim 8 , wherein
the cyclic carbonate solvent comprises one or more of ethylene carbonate EC, propylene carbonate PC, vinylene carbonate VC, fluoroethylene carbonate FEC, difluoroethylene carbonate DFEC, vinyl ethylene carbonate VEC, and dicaprylyl carbonate CC; and/or
the linear carbonate solvent comprises one or more allyl ethyl carbonate AEC, diphenyl carbonate DPC, and methyl allyl carbonate MAC, polycarbonate VA, diethyl carbonate DEC, methyl ethyl carbonate EMC, methyl propyl carbonate MPC, ethyl propyl carbonate EPC, methyl butyl carbonate MBC, methyl acetate MA, ethyl acetate EA, methyl propionate MP, and ethyl propionate EP.
10 . The secondary battery as claimed in claim 1 , wherein the positive electrode plate comprises a positive electrode active material, and the positive electrode active material has a molecular formula of LiNi x Co y Mn z M 1-x-y-z O 2 or LiNi a Co b Al c N 1-a-b-c O 2 , in which M and N are each independently selected from Co, Ni, Mn, Mg, Cu, Zn, A1, Sn, B, Ga, Cr, Sr, V, and Ti, and 0≤y≤1, 0≤x<1, 0≤z≤1, x+y+z≤, 0≤a≤1, 0≤b≤1, 0≤c≤1, a+b+c≤1.
11 . A battery module, comprising the secondary battery according to claim 1 .
12 . A battery pack, comprising the battery module according to claim 11 .
13 . An electrical device, comprising the secondary battery according to claim 1 .
14 . An electrical device, comprising the battery module according to claim 11 .
15 . An electrical device, comprising the battery pack according to claim 12 .