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CN-122025534-A - Winding structure battery core pole piece and winding battery

CN122025534ACN 122025534 ACN122025534 ACN 122025534ACN-122025534-A

Abstract

The invention provides a winding structure battery cell pole piece and a winding battery, wherein the winding structure battery cell pole piece comprises a pole piece body, a first active coating and a second active coating are respectively arranged on the two side surfaces of the pole piece body, the surface density of the first active coating is smaller than that of the second active coating, and one side of the first active coating is close to a winding center when the pole piece body is wound to form a winding core structure. According to the invention, active coatings with different surface densities are adopted on two sides of the pole piece, so that the risk of breakage of the pole piece during folding is reduced, and the energy density of the battery is improved.

Inventors

  • PANG JIAYU
  • WANG XIANG
  • XU SHENGWANG
  • LI HUI
  • XIAO HAIYAN

Assignees

  • 惠州赣锋锂电科技有限公司

Dates

Publication Date
20260512
Application Date
20260206

Claims (10)

  1. 1. The winding structure battery cell pole piece is characterized by comprising a pole piece body, wherein a first active coating and a second active coating are respectively arranged on the surfaces of two sides of the pole piece body, the surface density of the first active coating is smaller than that of the second active coating, and one side of the first active coating is close to a winding center when the pole piece body is wound to form a winding core structure.
  2. 2. The wound structure battery cell pole piece of claim 1, wherein the ratio of the areal density of the first active coating to the areal density of the second active coating is 1 (1.2-2).
  3. 3. The wound structure cell pole piece of claim 1 or 2, wherein the areal density of the first active coating is 120g/m 2 ~230g/m 2 .
  4. 4. The wound structure cell pole piece of claim 1 or 2, wherein the areal density of the second active coating is 150g/m 2 ~360g/m 2 .
  5. 5. The wound structure battery cell pole piece of claim 1, wherein the first active coating and the second active coating each independently comprise an active material, a conductive agent, and a binder; The content of the conductive agent in the first active coating is less than or equal to the content of the conductive agent in the second active coating.
  6. 6. The winding structure battery cell pole piece according to claim 5, wherein the mass ratio of the conductive agent in the first active coating is 0.5% -1.0% based on 100% of the total mass of the first active coating; And/or, the mass ratio of the conductive agent in the second active coating is 0.8% -1.5% based on 100% of the total mass of the second active coating.
  7. 7. The wound structure battery cell pole piece of claim 1 or 5, wherein the content of binder in the first active coating is less than or equal to the content of binder in the second active coating.
  8. 8. The winding structure battery cell pole piece according to claim 7, wherein the mass ratio of the binder in the first active coating is 0.7% -1.3% based on 100% of the total mass of the first active coating; And/or, the mass ratio of the binder in the second active coating is 0.9% -1.5% based on 100% of the total mass of the second active coating.
  9. 9. The winding structure battery cell electrode sheet according to any one of claims 5 to 8, wherein the mass ratio of the active material in the first active coating layer is 97.7% -98% based on 100% of the total mass of the first active coating layer; and/or, based on the total mass of the second active coating being 100%, the mass ratio of the active material in the second active coating is 97% -98.3%.
  10. 10. A wound battery comprising a positive electrode sheet and a negative electrode sheet, wherein the positive electrode sheet adopts the wound structure battery cell sheet of any one of claims 1-9.

Description

Winding structure battery core pole piece and winding battery Technical Field The invention belongs to the field of batteries, relates to a winding battery, and in particular relates to a winding structure battery core pole piece and a winding battery. Background Along with the higher energy density requirement of the market on the battery core, the foil is thinner, the coating amount of active substances on the foil is continuously increased, and the compaction of pole piece materials is continuously improved. The coating amount of active substances on both sides of the cell foil of the existing winding structure is generally the same. The upper side and the lower side of a battery pole piece current collector of a lithium ion battery pole piece are respectively coated with a first heat-sensitive and pressure-sensitive functional coating and a second heat-sensitive and pressure-sensitive functional coating by utilizing heat-sensitive and pressure-sensitive functional coating slurry prepared by dispersing a solvent, wherein the outer sides of the first heat-sensitive and pressure-sensitive functional coating and the second heat-sensitive and pressure-sensitive functional coating are respectively coated with a first active material layer and a second active material layer, the thicknesses of the first heat-sensitive and pressure-sensitive functional coating and the second heat-sensitive and pressure-sensitive functional coating are respectively 0.5-20 mu m, and the thicknesses of the first active material layer and the second active material layer are respectively 10-500 mu m. The positive plate disclosed by CN114141985A comprises a positive current collector and a positive coating, wherein the positive coating comprises a first coating and a second coating, the first coating is coated on the surface of the positive current collector, the second coating is coated on the surface of the first coating, the thickness of the first coating is 2-10 mu m, and the thickness of the second coating is 30-80 mu m. However, the innermost layer of the pole piece can be approximately 360-degree folded in half in the winding process, the foil needs to be stretched in the folding process, the breaking elongation of the foil is low, the pole piece is broken easily due to the limit design, and then the pole piece cannot play a role, so that the capacity of the battery cell is reduced, and the use of a user is affected. Therefore, in order to ensure battery performance, it is very important how to avoid the problem of breakage of the pole piece at the time of winding. Disclosure of Invention Aiming at the defects existing in the prior art, the invention aims to provide a winding structure battery cell pole piece and a winding battery, wherein different coating amounts are designed on two sides of the pole piece, so that the coating amount of the inner side is lower than that of the outer side, further higher compaction surface density is realized, and the problem that the pole piece is broken when folded in half is avoided. To achieve the purpose, the invention adopts the following technical scheme: In a first aspect, the invention provides a winding structure battery cell pole piece, which comprises a pole piece body, wherein a first active coating and a second active coating are respectively arranged on two side surfaces of the pole piece body, the surface density of the first active coating is smaller than that of the second active coating, and one side of the first active coating is close to a winding center when the pole piece body is wound to form a winding core structure. In a preferred embodiment of the present invention, the ratio of the areal density of the first active coating layer to the areal density of the second active coating layer is 1 (1.2-2), for example, 1:1.2, 1:1.3, 1:1.4, 1:1.5, 1:1.6, 1:1.7, 1:1.8, 1:1.9 or 1:2.0, but not limited to the recited values, and other non-recited values within the range of values are equally applicable. As a preferred embodiment of the present invention, the surface density of the first active coating layer is 120g/m 2~230g/m2, for example 120g/m2、130g/m2、140g/m2、150g/m2、160g/m2、170g/m2、180g/m2、190g/m2、200g/m2、210g/m2、220g/m2 or 230g/m 2, but is not limited to the values listed, and other values not listed in the range are equally applicable. As a preferred embodiment of the present invention, the second active coating layer has an areal density of 150g/m 2~360g/m2, for example 150g/m2、160g/m2、170g/m2、180g/m2、200g/m2、220g/m2、250g/m2、260g/m2、270g/m2、280g/m2、300g/m2、310g/m2、320g/m2、340g/m2、350g/m2 or 360g/m 2, but is not limited to the values listed, and other values not listed in this range are equally applicable. As a preferred embodiment of the present invention, the first active coating layer and the second active coating layer include an active material, a conductive agent and a binder, respectively. The content of the conductive agent in the first active coating is less th