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CN-224232647-U - Cathode single-sided area, cathode pole piece, secondary battery and electronic device

CN224232647UCN 224232647 UCN224232647 UCN 224232647UCN-224232647-U

Abstract

The utility model relates to the technical field of batteries, in particular to a cathode single-sided area, a cathode pole piece, a secondary battery and an electronic device. The cathode single-sided area comprises a cathode current collector and a cathode active material layer coated on one surface of the cathode current collector, the cathode single-sided area is provided with a strip-shaped corrugated array, the strip-shaped corrugated array comprises a plurality of strip-shaped concave parts and a plurality of strip-shaped convex parts, the strip-shaped concave parts are arranged on the surface, far away from the cathode active material layer, of the cathode current collector, the strip-shaped convex parts are arranged on the surface, far away from the cathode current collector, of the cathode active material layer, and the strip-shaped convex parts and the strip-shaped concave parts are in one-to-one correspondence. The cathode single-sided area structure of the utility model forms a dynamic counteracting mechanism with the tensile stress generated by material expansion during electrochemical circulation through the residual compressive stress field induced by the curvature of the micro-curved surface.

Inventors

  • LUO ZHONGCAN
  • CAI JIANWEN
  • JIA XING

Assignees

  • 东莞维科电池有限公司

Dates

Publication Date
20260512
Application Date
20250530

Claims (10)

  1. 1. The utility model provides a negative pole single face district, its characterized in that includes the negative pole electric current collector and coats in the negative pole active material layer of a negative pole electric current collector surface, negative pole single face district is provided with banding type ripple array, banding type ripple array includes many strip concave parts and many strip convex parts, many the strip concave parts set up in the negative pole electric current collector keeps away from the surface on negative pole active material layer, many the strip concave parts are followed the length direction interval setting of negative pole electric current collector, many the strip convex parts set up in the negative pole active material layer keeps away from the surface on negative pole electric current collector, many the strip convex parts are followed the length direction interval setting of negative pole active material layer, many the strip convex parts with many the strip concave parts one-to-one.
  2. 2. The cathode single-sided region according to claim 1, wherein the structure of the cathode single-sided region satisfies the relation S= (L1-L0)/2 h, 5% +≤L 1-L0)/L0.times.100% +≤10%; S is the number of the strip-shaped concave parts or the strip-shaped convex parts on the single-sided area of the cathode; l1 is the length of the cathode single-sided area after extension; l0 is the length of the cathode single-sided area before extension; H0 is the vertical distance from the lowest point of the strip-shaped concave portion to the plane of the cathode current collector away from the cathode active material layer.
  3. 3. A cathode single-sided region as claimed in claim 2, characterized in that the length L0 of the cathode single-sided region before extension is 100-200mm, and/or, The length L1 of the cathode single-sided area after extension is 105-220mm.
  4. 4. A cathode single-sided region according to claim 3, wherein the number of the strip-shaped concave portions is 13 to 2000, and/or the number of the strip-shaped convex portions is 13 to 2000.
  5. 5. The cathode single-sided region according to claim 4, wherein a vertical distance from a lowest point of the strip-shaped concave portion to a plane of the cathode current collector away from the cathode active material layer is 5 to 200 μm, and/or a vertical distance from an apex of the strip-shaped convex portion to a plane of the cathode active material layer away from the cathode current collector is 5 to 200 μm.
  6. 6. A cathode single-sided region according to claim 1, wherein the cross-section of the strip-shaped concave portion and the strip-shaped convex portion is elliptical or polygonal.
  7. 7. A cathode sheet comprising the cathode single-sided region of any one of claims 1-6, said cathode single-sided region being located at one end of the cathode sheet in the length direction.
  8. 8. A secondary battery comprising an electrode assembly comprising the cathode sheet of claim 7.
  9. 9. The secondary battery according to claim 8, wherein the electrode assembly is a rolled electrode assembly, and the cathode single-sided region is located at an outermost ring of the electrode assembly.
  10. 10. An electronic device comprising the secondary battery according to claim 8 or 9.

Description

Cathode single-sided area, cathode pole piece, secondary battery and electronic device Technical Field The utility model relates to the technical field of batteries, in particular to a cathode single-sided area, a cathode pole piece, a secondary battery and an electronic device. Background The silicon-carbon composite anode material of the lithium ion battery is regarded as a core technical path of the next generation of high-energy-density battery because of high theoretical specific capacity (3580 mAh/g) and low cost. However, the volume expansion effect of up to 300% in the lithium intercalation/deintercalation process induces the dynamic reconstruction of the three-dimensional stress of the electrode system, resulting in the formation of a significant stress concentration effect in the R corner region of the cell. From a micromechanics perspective analysis, the silicon particles undergo amorphous-to-crystalline phase transformation during lithiation, and the anisotropic expansion behavior thereof generates shear stress at the electrode-current collector interface, and particularly in the region of abrupt change of topological curvature of the cell R angle, the stress field shows geometric progression. The periodic mechanical load is transmitted to the aluminum foil substrate through the interface of the current collector and the active material, dislocation multiplication and slip zone formation are induced, and finally, the aluminum foil is subject to crystal penetration fracture or crystal brittle fracture, particularly, the aluminum foil in the single-sided area of the cathode pole piece is more likely to fracture, the single-sided area of the cathode pole piece is generally positioned at the outermost ring of the wound battery, and only one side of the current collector, which is close to the inside of the battery, is coated with the active material. And the exposed active substances after the aluminum foil is broken are in direct contact with the electrolyte, so that side reaction aggravation and interface SEI film overgrowth can be caused, and irreversible capacity attenuation and potential safety hazard are caused. Disclosure of utility model The first object of the present utility model is to overcome the defects of the prior art, and provide a single-sided area of a cathode, so as to solve the technical problem that the single-sided area of the cathode pole piece of the existing winding battery is easy to break. In order to solve the technical problems, the utility model adopts the following technical scheme: The utility model provides a single face district of negative pole, its includes the negative pole electric current collector and coats in the negative pole active material layer of a negative pole electric current collector surface, the single face district of negative pole is provided with stripiness class ripple array, stripiness class ripple array includes many strip concave parts and many strip convex parts, many the strip concave part set up in the negative pole electric current collector keeps away from the surface of negative pole active material layer, many the strip concave part sets up along the length direction interval of negative pole electric current collector, many the strip convex part set up in the negative pole active material layer keeps away from the surface of negative pole electric current collector, many the strip convex part sets up along the length direction interval of negative pole active material layer, many the strip convex part with many the strip concave part one-to-one. Further, the structure of the cathode single-sided region satisfies the relation S= (L1-L0)/2 h, and is more than or equal to 5% (L1-L0)/L0 multiplied by 100 percent and less than or equal to 10 percent; S is the number of the strip-shaped concave parts or the strip-shaped convex parts on the single-sided area of the cathode; l1 is the length of the cathode single-sided area after extension; l0 is the length of the cathode single-sided area before extension; H0 is the vertical distance from the lowest point of the strip-shaped concave portion to the plane of the cathode current collector away from the cathode active material layer. Further, the length L0 of the cathode single-sided region before extension is 100-200mm, and/or, The length L1 of the cathode single-sided area after extension is 105-220mm. Further, the number of the strip-shaped concave parts is 13-2000, and/or the number of the strip-shaped convex parts is 13-2000. Further, the vertical distance from the lowest point of the strip-shaped concave portion to the plane of the cathode current collector away from the cathode active material layer is 5-200 μm, and/or the vertical distance from the peak of the strip-shaped convex portion to the plane of the cathode active material layer away from the cathode current collector is 5-200 μm. Further, the cross sections of the strip-shaped concave parts and the strip-shaped convex parts ar