Long-life secondary battery, battery module, battery pack, and power consumption apparatus
Provided are a secondary battery which includes a positive electrode sheet, a negative electrode sheet, and a separator placed between the positive electrode sheet and the negative electrode sheet. In some embodiments, the positive electrode sheet includes a positive electrode current collector and positive film layers A1 and B1 respectively provided on two surfaces of the positive electrode current collector, and the negative electrode sheet includes a negative electrode current collector and negative film layers respectively provided on two surfaces of the negative electrode current collector, where capacities per unit area Cap A1 and Cap B1 of the positive film layers A1 and B1 satisfy Cap A1<Cap B1, and the negative electrode current collector of the negative electrode sheet is provided with at least one through hole.
1 . A secondary battery, comprising a positive electrode sheet, a negative electrode sheet, and a separator placed between the positive electrode sheet and the negative electrode sheet,
the positive electrode sheet comprising a positive electrode current collector and positive film layers A1 and B1 respectively provided on two surfaces of the positive electrode current collector, and the negative electrode sheet comprising a negative electrode current collector and negative film layers respectively provided on two surfaces of the negative electrode current collector,
wherein each of the positive electrode film layers comprises a positive electrode active material selected from a lithium-containing phosphate of an olivine structure and a lithium transition metal oxide,
wherein each of the negative electrode film layers comprises a negative electrode active material comprising artificial graphite,
wherein capacities per unit area Cap A1 and Cap B1 of the positive film layers A1 and B1 satisfy 0.7<Cap A1/Cap B1<0.9,
wherein a negative film layer provided opposite to and separated from the positive film layer A1 by a separator is A2, and capacities per unit area Cap A2 and Cap A1 of the negative film layer A2 and the positive film layer A1 satisfy 1.02<Cap A2/Cap A1≤1.2,
and the negative electrode current collector of the negative electrode sheet is provided with at least one through hole.
2 . The secondary battery according to claim 1 , wherein a negative film layer provided opposite to and separated from the positive film layer B1 by a separator is B2, and capacities per unit area Cap B2 and Cap B1 of the negative film layer B2 and the positive film layer B1 satisfy max (Cap A1/Cap B1, (Cap B1+Cap A1-Cap A2)/Cap B1)≤Cap B2/Cap B1≤1.
3 . The secondary battery according to claim 1 , wherein a ratio of an area of the through hole to an area of the negative electrode current collector is 0.2%-40%.
4 . The secondary battery according to claim 1 , wherein a pore diameter of the through hole is 5-500 μm.
5 . The secondary battery according to claim 1 , wherein compacted density of the positive electrode sheet is 2.0-3.6 g/cc.
6 . The secondary battery according to claim 1 , wherein compacted density of the negative electrode sheet is 0.5-2 g/cc.
7 . The secondary battery according to claim 1 , wherein a pore diameter of the through hole is 200-500 μm.
8 . The secondary battery according to claim 1 , wherein a thickness of the positive film layer A1 is 51 μm to 87 μm, a thickness of the negative film layer A2 is 55 μm to 70 μm.
9 . The secondary battery according to claim 1 , wherein a thickness of the positive film layer B1 is 64 μm to 144 μm, a thickness of the negative film layer B2 is 57 μm to 77 μm.
10 . A battery module, wherein the battery module comprises the secondary battery according to claim 1 .
11 . A battery pack, wherein the battery pack comprises the battery module according to claim 10 .
12 . A power consumption apparatus, wherein the power consumption apparatus comprises the secondary battery according to claim 1 .
13 . A power consumption apparatus, wherein the power consumption apparatus comprises the battery module according to claim 10 .
14 . A power consumption apparatus, wherein the power consumption apparatus comprises the battery pack according to claim 11 .