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CN-122026018-A - Electrode assembly and battery

CN122026018ACN 122026018 ACN122026018 ACN 122026018ACN-122026018-A

Abstract

The application discloses an electrode assembly and a battery, and belongs to the technical field of batteries. The electrode assembly comprises a pole piece, the pole piece comprises a current collector and an active material layer, the current collector comprises a body, a transition part and a pole lug which are sequentially connected along a first direction, the active material layer is at least arranged on the body, the thickness of the body is T 1 , the thickness of the pole lug is T 2 , T 2 ＞T 1 is gradually increased along the first direction, the thickness of the transition part is gradually increased, the number of core layers of the electrode assembly is N 1 , and the number of layers of the pole lug in the electrode assembly is N 2 , wherein T 2 =(n 1 ×T 1 ×N 2 )/N 1 ,1≤n 1 is less than or equal to 5. Through the thickness T 2 of the tab in the mode, on one hand, the situation that tearing improvement is not obvious due to too small T 2 can be prevented, on the other hand, transition part folds are deformed due to too large T 2 can be prevented, tab tearing caused by external folds is increased, and meanwhile the risk that the uppermost tab in the electrode assembly is torn due to longer stroke is reduced.

Inventors

  • ZHAO YUNXIA

Assignees

  • 湖北亿纬动力有限公司

Dates

Publication Date
20260512
Application Date
20251231

Claims (10)

  1. 1. The electrode assembly is characterized by comprising a pole piece, wherein the pole piece comprises a current collector and an active material layer, the current collector comprises a body, a transition part and a pole lug which are sequentially connected along a first direction, the active material layer is at least arranged on the body, the thickness of the body is T 1 , the thickness of the pole lug is T 2 , T 2 ＞T 1 is gradually increased along the first direction, the number of core layers of the electrode assembly is N 1 , and the number of layers of the pole lug in the electrode assembly is N 2 , wherein T 2 =(n 1 ×T 1 ×N 2 )/N 1 ,1≤n 1 is less than or equal to 5.
  2. 2. The electrode assembly of claim 1, wherein 2.16 n 1 n 2.83.
  3. 3. The electrode assembly according to claim 1 or 2, wherein T 1 . Ltoreq.15 μm and/or T 2 . Ltoreq.20 μm are/is 2 μm.
  4. 4. The electrode assembly of any one of claims 1 to 3, wherein 1≤N 1 ≤300, and/or 1≤N 2 ≤200.
  5. 5. The electrode assembly according to any one of claims 1 to 4, wherein a welding region is formed on the tab, a distance between an edge of the active material layer and the transition portion in the first direction is H 1 , a width of the transition portion is H 2 , and a distance between the edge of the active material layer and the welding region is H 3 , wherein H 2 =n 2 ×(T 1 /T 2 )×(H 3 -H 1 ),0＜n 2 is less than or equal to 10.
  6. 6. The electrode assembly of claim 5, wherein 0.92 n 2 1.2.
  7. 7. The electrode assembly of claim 5, wherein-50 mm < H 1 < 50mm, and/or 0<H 2 < 50mm, and/or 0<H 3 < 100mm.
  8. 8. The electrode assembly according to any one of claims 1 to 7, wherein the active material layer extends onto the transition portion, and/or the electrode assembly is a wound structure.
  9. 9. The electrode assembly according to any one of claims 1 to 8, wherein the electrode assembly comprises a positive electrode sheet, a separator and a negative electrode sheet which are stacked, the separator is located between the positive electrode sheet and the negative electrode sheet, and at least one of the positive electrode sheet and the negative electrode sheet is the electrode sheet.
  10. 10. A battery comprising the electrode assembly according to any one of claims 1 to 9.

Description

Electrode assembly and battery Technical Field The present application relates to the field of battery technologies, and in particular, to an electrode assembly and a battery. Background In order to reduce the weight and cost of current collectors, current collectors tend to be ultra-thin in design, and the thickness of the tab and the material area are consistent. However, in the production process of the core pack, when the tab is welded and glued, the tab is torn due to the fact that the tab is thinner. Disclosure of Invention The embodiment of the application provides an electrode assembly and a battery, which are used for at least partially solving the technical problems. In order to achieve the above object, according to a first aspect of the present application, there is provided an electrode assembly including a electrode sheet including a current collector and an active material layer, the current collector including a body, a transition portion, and a tab sequentially connected in a first direction, the active material layer being disposed at least on the body, the thickness of the body being T 1, the thickness of the tab being T 2, wherein T 2＞T1, in the first direction, the thickness of the transition portion gradually increases, the number of core layers of the electrode assembly being N 1, the number of layers of the tab being N 2, wherein T 2=(n1×T1×N2)/N1,1≤n1 is less than or equal to 5. In the embodiment of the application, the thickness T 2 of the tab is positively correlated with the thickness T 1 of the body, the larger the T 1 is, the larger the corresponding T 2 is, the positive correlation of the T 2 and the ratio of the number N 2 of the tab in the core-in-layer number N 1 is also, the larger the number of the tab is, the larger the ratio of the number of the tab in the core-in-layer number is, and the larger the thickness T 2 of the tab is. Through the thickness T 2 of the tab in the mode, on one hand, the situation that the tearing improvement is not obvious due to too small T 2 can be prevented, on the other hand, the transition part is prevented from being folded and deformed due to too large T 2, the tab tearing caused by external folds is increased, and meanwhile, the risk that the uppermost tab in the electrode assembly is torn due to longer stroke is reduced. Alternatively, the process may be carried out in a single-stage, n 1 is less than or equal to 2.16 and less than or equal to 2.83. When n 1 is within this range, the thickness T 2 of the tab can be well matched with the structure of the electrode assembly, thereby controlling the tear rate of the tab to a relatively low level. Optionally, T 1 & lt 15 & gtm & lt 2 & gtm & lt 15 & gtm, and/or T 2 & lt 20 & gtm & lt 2 & gtm. Through the thickness T 1 of control body and the thickness T 2 of utmost point ear, can make the mass flow body have cost advantage and better anti tearing ability concurrently. Alternatively, the process may be carried out in a single-stage, N 1 is more than or equal to 1 and less than or equal to 300; and/or the number of the groups of groups, N 2 is less than or equal to 1 and less than or equal to 200. Since the T 2 is positively related to the ratio of the number of layers N 2 of the tab in the number of core-spun layers N 1, the tearing rate of the tab can be optimized by controlling the number of core-spun layers N 1 and the number of layers N 2 of the tab. Optionally, a welding area is formed on the tab, in the first direction, the distance between the edge of the active material layer and the transition portion is H 1, the width of the transition portion is H 2, and the distance between the edge of the active material layer and the welding area is H 3, wherein H 2=n2×(T1/T2)×(H3-H1),0＜n2 is less than or equal to 10. If H 2 is too small, the transition part is gradually changed faster, the stress of the material is concentrated, the winding tension difference is larger, the tearing of the welding area of the tab is reduced, but the tearing of the transition part is increased, while when H 2 is too large, the transition part extends to the welding area, the thickness of the foil at the welding edge is inconsistent, the welding consistency is affected, and the risk of tearing of the tab is increased. Controlling the width H 2 of the transition in the above manner facilitates reducing the risk of tab tearing. Alternatively, the process may be carried out in a single-stage, n 2 is more than or equal to 0.92 and less than or equal to 1.2. The tearing rate of the tab can be controlled within a lower level within the above range of values of n 2. Optionally, -50mm < H 1 > 50mm, and/or 0<H 2 > 50mm, and/or 0<H 3 > 100mm. Optionally, the active material layer extends onto the transition. That is, at least part of the transition is covered by the active material layer, which to some extent may support and protect the transition, reducing the risk of tearing of the transition. Optionally, the electrode as