POSITIVE ELECTRODE PLATE, LITHIUM-ION SECONDARY BATTERY, BATTERY MODULE, BATTERY PACK, AND ELECTRICAL DEVICE
This application provides a positive electrode plate, a lithium-ion secondary battery, a battery module, a battery pack, and an electrical device. The positive electrode plate of this application includes: a current collector, a first coating layer applied on both sides of the current collector, and a second coating layer applied on a surface of the first coating layer. The first coating layer contains a small-grained olivine-structured phosphate compound, and a particle diameter of the small-grained olivine-structured phosphate compound is 0.5 to 2 μm. The second coating layer contains: a large-grained olivine-structured phosphate compound and a layered transition metal oxide; or a large-grained olivine-structured phosphate compound and a pure layered transition metal oxide. A particle diameter of the large-grained olivine-structured phosphate compound is larger than a particle diameter of the small-grained olivine-structured phosphate compound.
1 . A positive electrode plate, wherein
the positive electrode plate comprises: a current collector, a first coating layer applied on both sides of the current collector, and a second coating layer applied on a surface of the first coating layer;
the first coating layer contains a small-grained olivine-structured phosphate compound, and a particle diameter of the small-grained olivine-structured phosphate compound is 0.5 to 2 μm; and
the second coating layer contains: a large-grained olivine-structured phosphate compound and a layered transition metal oxide; or a large-grained olivine-structured phosphate compound and a pure layered transition metal oxide, and a particle diameter of the large-grained olivine-structured phosphate compound is larger than a particle diameter of the small-grained olivine-structured phosphate compound.
2 . The positive electrode plate according to claim 1 , wherein
the olivine-structured phosphate compound is at least one selected from lithium iron phosphate or lithium manganese iron phosphate.
3 . The positive electrode plate according to claim 1 , wherein
the layered transition metal oxide is at least one selected from lithium cobalt oxide, lithium nickel cobalt manganese oxide, or lithium nickel cobalt aluminum oxide; and
the pure layered transition metal oxide is at least one selected from lithium nickel cobalt manganese oxide or lithium nickel cobalt aluminum oxide.
4 . The positive electrode plate according to claim 1 , wherein a thickness of the first coating layer is 2 to 200 μm, and optionally 30 to 100 μm.
5 . The positive electrode plate according to claim 1 , wherein a thickness of the second coating layer is 2 to 400 μm, and optionally 50 to 200 μm.
6 . A lithium-ion secondary battery, wherein the lithium-ion secondary battery comprises the positive electrode plate according to claim 1 .
7 . A battery module, wherein
the battery module comprises the lithium-ion secondary battery according to claim 6 .
8 . A battery pack, wherein
the battery pack comprises the battery module according to claim 7 .
9 . An electrical device, wherein
the electrical device comprises the battery pack according to claim 8 .