Electrode assembly, battery cell, battery, manufacturing method and device for electrode assembly
An embodiment of the present application provides an electrode assembly, a battery cell, a battery, and a manufacturing method and device for the electrode assembly, which belong to the technical field of batteries. The electrode assembly includes a negative electrode plate and a positive electrode plate. The negative electrode plate includes a negative active material layer located in the straight area, and the positive electrode plate includes a positive active material layer located in the straight area. A first direction is perpendicular to an axial direction of a winding structure. The negative active material layer includes a negative electrode main body portion and negative electrode edge portions located on both sides of the negative electrode main body portion. The electrode assembly of this structure can effectively reduce the risk of lithium plating and improve the safety of the battery.
1. An electrode assembly, comprising a negative electrode plate and a positive electrode plate, wherein:
the negative electrode plate and the positive electrode plate are laminated and wound to form a winding structure having a straight area, the negative electrode plate comprises a negative active material layer located in the straight area, the positive electrode plate comprises a positive active material layer located in the straight area and disposed opposite to the negative active material layer in a first direction, and the first direction is perpendicular to an axial direction of the winding structure;
the negative active material layer comprises a negative electrode main body portion and a negative electrode edge portion on both sides of the negative electrode main body portion in the axial direction, in the first direction, at least a part of the negative electrode main body portion and at least a part of the negative electrode edge portion on both sides of the negative electrode main body portion overlap with the positive active material layer, an active substance capacity per unit area of the negative electrode main body portion is greater than an active substance capacity per unit area of the negative electrode edge portion; and the positive active material layer comprises a positive electrode main body portion and a positive electrode edge portion on both sides of the positive electrode main body portion in the axial direction, in the first direction, at least a part of the positive electrode main body portion and at least a part of the positive electrode edge portion on both sides of the positive electrode main body portion overlap with the negative active material layer, an active substance capacity per unit area of the positive electrode main body portion is less than an active substance capacity per unit area of the positive electrode edge portion;
in the first direction, two ends of the negative electrode main body portion in the axial direction are aligned with two ends of the positive electrode main body portion in the axial direction, respectively;
the positive electrode plate further comprises a positive electrode current collecting body, and the positive electrode main body portion comprises a first positive electrode coating layer and a second positive electrode coating layer arranged at a same side of the positive electrode current collecting body, and the first positive electrode coating layer and the second positive electrode coating layer being laminated and arranged in the first direction, and comprising different materials or having different compositions;
the first positive electrode coating layer is a metal conductive layer without active material; and
the second positive electrode coating layer is coated on the positive electrode current collecting body, and the first positive electrode coating layer is coated on one side of the second positive electrode coating layer facing away from the positive electrode current collecting body.
2. The electrode assembly according to claim 1 , wherein a gram capacity of an active material of the negative electrode main body portion is greater than a gram capacity of an active material of the negative electrode edge portion, wherein:
the gram capacity of the active material of the negative electrode main body portion is a ratio of a capacitance released by the active material of the negative electrode main body portion to a mass of the active material of the negative electrode main body portion, and
the gram capacity of the active material of the negative electrode edge portion is a ratio of a capacitance released by the active material of the negative electrode edge portion to a mass of the active material of the negative electrode edge portion.
3. The electrode assembly according to claim 1 , wherein a ratio of a weight of the active material of the negative electrode main body portion to a weight of the negative electrode main body portion is greater than a ratio of a weight of the active material of the negative electrode edge portion to a weight of the negative electrode edge portion.
4. The electrode assembly according to claim 1 , wherein a gram capacity of an active material of the positive electrode main body portion is less than a gram capacity of an active material of the positive electrode edge portion, wherein:
the gram capacity of the active material of the positive electrode main body portion is a ratio of a capacitance released by the active material of the positive electrode main body portion to a mass of the active material of the positive electrode main body portion, and
the gram capacity of the active material of the positive electrode edge portion is a ratio of a capacitance released by the active material of the positive electrode edge portion to a mass of the active material of the positive electrode edge portion.
5. The electrode assembly according to claim 4 , wherein a gram capacity of an active material of the first positive electrode coating layer is less or equal to a gram capacity of an active material of the positive electrode edge portion, and a gram capacity of an active material of the second positive electrode coating layer is less than the gram capacity of the active material of the first positive electrode coating layer, wherein:
the gram capacity of the active material of the positive electrode edge portion is a ratio of a capacitance released by the active material of the positive electrode edge portion to a mass of the active material of the positive electrode edge portion,
the gram capacity of the active material of the first positive electrode coating layer is a ratio of a capacitance released by the active material of the first positive electrode coating layer to a mass of the active material of the first positive electrode coating layer, and
the gram capacity of the active material of the second positive electrode coating layer is a ratio of a capacitance released by the active material of the second positive electrode coating layer to a mass of the active material of the second positive electrode coating layer.
6. The electrode assembly according to claim 1 , wherein a ratio of a weight of the active material of the positive electrode main body portion to a weight of the positive electrode main body portion is less than a ratio of a weight of the active material of the positive electrode edge portion to a weight of the positive electrode edge portion.
7. The electrode assembly according to claim 1 , wherein a thickness of the positive electrode main body portion is less than a thickness of the positive electrode edge portion.
8. The electrode assembly according to claim 1 , wherein the negative electrode main body portion and the negative electrode edge portion are continuously distributed in the axial direction.
9. The electrode assembly according to claim 1 , wherein the positive electrode main body portion and the positive electrode edge portion are continuously distributed in the axial direction.
10. A battery cell, comprising a shell and the electrode assembly according to claim 1 ; and
the electrode assembly being accommodated in the shell.
11. A battery, comprising a box body and the battery cell according to claim 10 ; and the battery cell electrode assembly being accommodated in the box body.
12. A power consumption device, comprising the battery according to claim 11 .
13. A manufacturing method for the electrode assembly according to claim 1 , comprising:
providing the negative electrode plate and the positive electrode plate; and
laminating and winding the negative electrode plate and the positive electrode plate to form the winding structure.
14. A manufacturing device for the electrode assembly according to claim 1 , comprising:
a providing apparatus, configured to provide the positive electrode plate and the negative electrode plate; and
an assembling apparatus, configured to laminate and wind the negative electrode plate and the positive electrode plate to form the winding structure.
15. The electrode assembly according to claim 1 , wherein:
the negative electrode main body portion and the negative electrode edge portion contain different active materials; and/or
the positive electrode main body portion and the positive electrode edge portion contain different active materials.
16. The electrode assembly according to claim 15 , wherein:
an active material of the negative electrode main body portion is silicon, and an active material of the negative electrode edge portion is graphite; and/or
an active material of the positive electrode main body portion is lithium iron phosphate, and an active material of the positive electrode edge portion is ternary lithium.
17. The electrode assembly according to claim 1 , wherein:
the negative electrode main body portion and the negative electrode edge portion are spaced apart from each other in the axial direction; and/or
the positive electrode main body portion and the positive electrode edge portion are spaced apart from each other in the axial direction.
18. The electrode assembly according to claim 1 , wherein a total thickness of the first positive electrode coating layer and the second positive electrode coating layer is equal to a thickness of the positive electrode edge portion.