Winding type electrode assembly, battery cell, battery and power consumption device
The embodiments of the present application provide a winding type electrode assembly including a positive electrode plate and a negative electrode plate; the positive electrode plate includes a first positive winding end portion and a positive winding middle section; the negative electrode plate includes a first portion and a second portion; and an active material layer of the negative electrode plate exceeds an active material layer of the positive electrode plate, and a difference between a maximum width of a negative active material layer of the first portion and a minimum width of a positive active material layer of the first positive winding end portion is larger than a difference between a maximum width of a negative active material layer of the second portion and a minimum width of a positive active material layer of the positive winding middle section.
1. A winding type electrode assembly, comprising:
a positive electrode plate comprising a first positive winding end portion, a second positive winding end portion and a positive winding middle section, wherein the first positive winding end portion and the second positive winding end portion are connected to two ends of the positive winding middle section respectively, the first positive winding end portion is a positive winding starting section, and the second positive winding end portion is a positive winding ending section; and
a negative electrode plate comprising a first portion and a second portion connected to each other, wherein the first portion is arranged opposite to the first positive winding end portion, and the second portion is arranged opposite to the positive winding middle section; and
in a winding axial direction of the winding type electrode assembly, a negative active material layer of the negative electrode plate exceeds a positive active material layer of the positive electrode plate, a maximum width of a negative active material layer of the first portion is H1, a minimum width of a positive active material layer of the first positive winding end portion is L1, a maximum width of a negative active material layer of the second portion is H2, a minimum width of a positive active material layer of the positive winding middle section is L2, and H1−L1>H2−L2.
2. The winding type electrode assembly according to claim 1 , wherein a minimum width of the negative active material layer of the first portion is H3, wherein H1>H2, and H3≥H2.
3. The winding type electrode assembly according to claim 2 , wherein in the winding axial direction, at least part of one end of the negative active material layer of the first portion exceeds a corresponding end of the negative active material layer of the second portion, and the other end of the negative active material layer of the first portion is flush with the other end of the negative active material layer of the second portion.
4. The winding type electrode assembly according to claim 3 , wherein the negative electrode plate further comprises a negative tab, in the winding axial direction, the negative tab is located at one end of the negative electrode plate, and one end of the negative active material layer of the first portion close to the negative tab at least partially exceeds a corresponding end of the negative active material layer of the second portion.
5. The winding type electrode assembly according to claim 1 , wherein 0.3 mm≤H1−H2≤3 mm.
6. The winding type electrode assembly according to claim 1 , wherein the negative electrode plate further comprises a negative tab, in the winding axial direction, the negative tab is located at one end of the negative electrode plate, one end of the first portion close to the negative tab exceeds a corresponding end of the second portion, and the other end of the first portion is flush with the other end of the second portion.
7. The winding type electrode assembly according to claim 6 , wherein in a winding direction of the winding type electrode assembly, the first portion is provided with a connection surface connected to the second portion; and
negative tabs are multiple in quantity, one of the multiple negative tabs protrudes out of the first portion in the winding axial direction and is provided with a first side face close to the second portion, and the first side face and the connection surface are coplanar.
8. The winding type electrode assembly according to claim 6 , wherein in the winding axial direction, the negative tab protruding out of the first portion is provided with a negative active material layer, and the negative active material layer on the negative tab protruding out of the first portion is connected to the negative active material layer of the first portion.
9. The winding type electrode assembly according to claim 1 , wherein the winding type electrode assembly comprises a straight area and two bent areas, and the two bent areas are connected to two ends of the straight area respectively; and
the first portion passes through the straight area at least two times.
10. The winding type electrode assembly according to claim 1 , wherein the negative electrode plate further comprises a third portion, the first portion and the third portion are connected to two ends of the second portion respectively, and the third portion is arranged opposite to the second positive winding end portion; and
a maximum width of a negative active material layer of the third portion is H4, a minimum width of a positive active material layer of the second positive winding end portion is L3, and H4−L3>H2−L2.
11. The winding type electrode assembly according to claim 10 , wherein a minimum width of the negative active material layer of the third portion is H5, wherein H4>H2, H5≥H2.
12. The winding type electrode assembly according to claim 1 , wherein a maximum width of the positive active material layer of the first positive winding end portion is L4, a maximum width of the positive active material layer of the positive winding middle section is L5, and L4<L5.
13. The winding type electrode assembly according to claim 12 , wherein in the winding axial direction, one end of the positive active material layer of the positive winding middle section at least partially exceeds a corresponding end of the positive active material layer of the first positive winding end portion, and the other end of the positive active material layer of the positive winding middle section is flush with the other end of the positive active material layer of the first positive winding end portion.
14. The winding type electrode assembly according to claim 13 , wherein the positive electrode plate further comprises a positive tab, in the winding axial direction, the positive tab is located at one end of the positive electrode plate, and one end of the positive active material layer of the positive winding middle section close to the positive tab at least partially exceeds a corresponding end of the positive active material layer of the first positive winding end portion.
15. A battery cell, comprising the winding type electrode assembly according to claim 1 .
16. A battery, comprising the battery cell according to claim 15 .
17. A power consumption device, comprising the battery cell according to claim 15 .