BATTERY PACK AND ELECTRICAL DEVICE CONTAINING SAME
A battery pack includes at least a first battery cell and a second battery cell. The battery pack includes a region A and a region B. The region A is a region of a low thermal insulation capability and is located on all sides and/or at a bottom of the battery pack. A remaining region is the region B. A percentage of a number of the first battery cells among battery cells in the region A is 10% to 100%. A percentage of a number of the second battery cells among battery cells in the region B is 5% to 100%.
1 . A battery pack, comprising:
at least a first battery cell and a second battery cell;
wherein:
the battery pack comprises a region A and a region B, the region A is a region of a low thermal insulation capability and is located on all sides and/or at a bottom of the battery pack, and a remaining region is the region B;
a percentage of a number of the first battery cells among battery cells in the region A is 10% to 100%, and a percentage of a number of the second battery cells among battery cells in the region B is 5% to 100%;
a volumetric energy density of the first battery cell and a volumetric energy density of the second battery cell are D 1 and D 2 respectively, an ionic conductivity of an electrolyte solution at −10° C. is σ 1 in the first battery cell and σ 2 in the second battery cell, K 1 =D 1 2 ×σ 1 and K 2 =D 2 2 ×σ 2 ;
when D 1 =D 2 , K 1 and K 2 satisfy 0.2<K 2 /K 1 ≤0.99; and
when D 1 ≠D 2 , K 1 and K 2 satisfy 1.01≤K 2 /K 1 ≤10.
2 . The battery pack according to claim 1 , wherein, when D 1 =D 2 , K 1 and K 2 satisfy 0.25≤K 2 /K 1 ≤0.98.
3 . The battery pack according to claim 1 , wherein, when D 1 ≠D 2 , K 1 and K 2 satisfy 1.02≤K 2 /K 1 ≤5.
4 . The battery pack according to claim 1 , wherein, when D 1 =D 2 , at −10° C., the ionic conductivity σ 1 of the electrolyte solution in the first battery cell and the ionic conductivity σ 2 of the electrolyte solution in the second battery cell satisfy 0<|σ 1 −σ 2 |<8 mS/cm.
5 . A battery pack, comprising:
at least a first battery cell and a second battery cell;
wherein:
the battery pack comprises a region A and a region B, the region A is a region of a low thermal insulation capability and is located on all sides and/or at a bottom of the battery pack, and a remaining region is the region B;
a percentage of a number of the first battery cells among battery cells in the region A is 10% to 100%, and a percentage of a number of the second battery cells among battery cells in the region B is 5% to 100%;
a volumetric energy density of the first battery cell and a volumetric energy density of the second battery cell are D 1 and D 2 respectively, a viscosity of an electrolyte solution at −10° C. is η 1 in the first battery cell and η 2 in the second battery cell, M 1 =D 1 /η 1 , and M 2 =D 2 /η 2 ;
when D 1 =D 2 , M 1 M 2 satisfy 0.2<M 2 /M 1 ≤0.99; and
when D 1 +D 2 , M 1 and M 2 satisfy 1.01≤M 2 /M 1 ≤10.
6 . The battery pack according to claim 5 , wherein, when D 1 =D 2 , M 1 and M 2 satisfy 0.25≤M 2 /M 1 ≤0.98.
7 . The battery pack according to claim 5 , wherein, when D 1 ≠D 2 , M 1 and M 2 satisfy 1.02≤M 2 /M 1 ≤9.
8 . The secondary battery according to claim 5 , wherein, when D 1 =D 2 , at −10° C., the viscosity η 1 of the electrolyte solution in the first battery cell and the viscosity η 2 of the electrolyte solution in the second battery cell satisfy 0<|η 2 −η 1 |<5 mPa·s.
9 . The battery pack according to claim 1 , wherein:
a percentage of a number of the first battery cells among the battery cells in the region A is 10% to 90%; and
a percentage of a number of the second battery cells among the battery cells in the region B is 20% to 100%.
10 . The battery pack according to claim 1 , wherein length-width diagonals of the battery pack in a horizontal direction are Lc, a region formed by connecting four points on the two diagonals is region B, each of the four points is at a distance of ⅕ Lc from an endpoint of the corresponding diagonal, and a remaining region is the region A.
11 . The battery pack according to claim 1 , wherein the battery cells in the battery pack are stacked in a plurality of layers, a vertical height of the battery pack is Ld, a region located below a point that is at a distance of ⅕ Ld from a bottom is the region A, and a remaining region corresponding to ⅘ Ld above the point is the region B.
12 . The battery pack according to claim 1 , wherein different regions in the battery pack are endowed with different thermal insulation capabilities, and at least two types of regions satisfy a condition that a temperature difference ΔT between the two types of regions falls within a range of 0<ΔT<10° C.
13 . The battery pack according to claim 1 , wherein a film-forming resistance Rct 1 of a positive electrode plate in the first battery cell and a film-forming resistance Rct 2 of a positive electrode plate in the second battery cell satisfy 1≤Rct 1 /Rct 2 ≤4.
14 . The battery pack according to claim 1 , wherein a coagulation point of the electrolyte solution of all battery cells in the battery pack is less than or equal to −20° C.
15 . The battery pack according to claim 1 , wherein a volumetric energy density D of both the first battery cell and the second battery cell satisfies 100 Wh/L<D<1000 Wh/L.
16 . The battery pack according to claim 1 , wherein, when D 1 ≠D 2 , the battery pack further comprises a third battery cell, the third battery cell is formed by a mixture of a main material system of the first battery cell and a main material system of the second battery cell, a volumetric energy density of the third battery cell is D 3 , and D 3 falls between D 1 and D 2 .
17 . The battery pack according to claim 16 , wherein:
an ionic conductivity of an electrolyte solution of the third battery cell at −10° C. is σ 3 , and K 3 =D 3 2 ×σ 3 falls between K 1 and K 2 ; or
a viscosity of an electrolyte solution of the third battery cell at −10° C. is η 3 , and M 3 =D 3 /η 3 falls between M 1 and M 2 .
18 . The battery pack according to claim 1 , wherein the battery cells each are independently selected from a lithium-ion battery, a lithium metal battery, or a sodium-ion battery.
19 . The battery pack according to claim 18 , wherein a chemical system of a positive active material of the battery cell is independently selected from a lithium nickel cobalt manganese system, a lithium iron phosphate system, a lithium manganese iron phosphate system, a lithium vanadium iron phosphate system, a lithium vanadium phosphate system, a lithium cobalt oxide system, a lithium nickel oxide system, a lithium-rich manganese system, a lithium nickel cobalt aluminum system, a lithium manganese oxide system, or a Prussian blue system, a polyanion-based system, an oxide-based system, or a dual-ion battery system.
20 . The battery pack according to claim 1 , comprising a first battery cells and b second battery cells, wherein a and b are both natural numbers greater than or equal to 1, and 0.01<a/b≤200.