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US-12627003-B2 - Separator and preparation method therefor, battery, and electric apparatus

US12627003B2US 12627003 B2US12627003 B2US 12627003B2US-12627003-B2

Abstract

This application discloses a separator and a preparation method therefor, a battery, and an electric apparatus. The separator includes a substrate and a pressure-sensitive coating, where the pressure-sensitive coating is formed on at least a portion of surface of the substrate. The pressure-sensitive coating includes composite particles and a first plasticizer. The composite particles form bulges on surface of the coating, and the composite particles include polyacrylate particles and inorganic particles. The inorganic particle is present between at least two of the polyacrylate particles, and solubility parameter of the first plasticizer and solubility parameter of the composite particles have a difference with an absolute value of 0.3 MPa 1/2 -4 MPa 1/2 .

Inventors

  • Xiaonan Cheng
  • Haiyi HONG
  • Yanyun MA
  • Jianrui YANG
  • Yi Zheng
  • Chengdong Sun

Assignees

  • CONTEMPORARY AMPEREX TECHNOLOGY (HONG KONG) LIMITED

Dates

Publication Date
20260512
Application Date
20240508
Priority Date
20220325

Claims (20)

  1. 1 . A separator, comprising: a substrate; and a pressure-sensitive coating, wherein the pressure-sensitive coating is formed on at least a portion of surface of the substrate, and the pressure-sensitive coating comprises composite particles and a first plasticizer, the composite particles form bulges on surface of the pressure-sensitive coating, and the composite particles comprise polyacrylate particles and inorganic particles, wherein the inorganic particle is present between at least two of the polyacrylate particles, and solubility parameter of the first plasticizer and solubility parameter of the composite particles have a difference with an absolute value of 0.3 MPa 1/2 -4 MPa 1/2 .
  2. 2 . The separator according to claim 1 , wherein the first plasticizer comprises an ester compound, and solubility parameter of the ester compound is 12 MPa 1/2 -30 MPa 1/2 .
  3. 3 . The separator according to claim 2 , wherein the pressure-sensitive coating further comprises an emulsifier, the emulsifier comprising at least one of an anionic emulsifier and a nonionic emulsifier.
  4. 4 . The separator according to claim 3 , wherein the pressure-sensitive coating comprises 80-96 parts by weight of composite particles, 5-30 parts by weight of ester compound, and 0.1-0.5 parts by weight of emulsifier.
  5. 5 . The separator according to claim 1 , wherein D v 50 of the composite particles is ≥2.5 μm, preferably 2.5 μm-10 μm, and more preferably 3 μm-8 μm.
  6. 6 . The separator according to claim 1 , wherein the composite particles comprise a first agglomerate, and the first agglomerate comprises at least two of the inorganic particles.
  7. 7 . The separator according to claim 6 , wherein 0.01 μm≤D v 50 of the first agglomerate ≤D v 10 of the composite particles.
  8. 8 . The separator according to claim 1 , wherein the composite particles comprise inorganic particles of primary particle morphology.
  9. 9 . The separator according to claim 8 , wherein D v 50 of the inorganic particles of primary particle morphology is 0.01 μm-1 μm, preferably 0.5 μm-1 μm.
  10. 10 . The separator according to claim 1 , wherein the composite particles comprise a second agglomerate, and the second agglomerate comprises at least two of the polyacrylate particles.
  11. 11 . The separator according to claim 10 , wherein D v 50 of the second agglomerate is 0.3 μm-5 μm, preferably 1 μm-2 μm.
  12. 12 . The separator according to claim 1 , wherein the polyacrylate particles comprise polyacrylate particles of primary particle morphology and/or polyacrylate particles of secondary particle morphology.
  13. 13 . The separator according to claim 12 , wherein D v 50 of the polyacrylate particles of primary particle morphology is 50 nm-400 nm, preferably 100 nm-200 nm.
  14. 14 . The separator according to claim 12 , wherein D v 50 of the polyacrylate particles of secondary particle morphology is 2 μm-15 μm, preferably 5 μm-8 μm.
  15. 15 . The separator according to claim 1 , wherein the polyacrylate particles have a glass transition temperature of 20° C.-80° C., preferably 25° C.-65° C.
  16. 16 . The separator according to claim 1 , wherein percentage of the inorganic particles in the composite particles is 1 wt %-50 wt %, optionally 1 wt %-40 wt %, more optionally 2 wt %-15 wt %, and most preferably 5 wt %-15 wt %.
  17. 17 . The separator according to claim 1 , wherein two-side height of the bulges is 15 μm-60 μm.
  18. 18 . The separator according to claim 1 , wherein the pressure-sensitive coating further comprises 4-20 parts by weight of pressure-sensitive adhesive polymer, the pressure-sensitive adhesive polymer comprising an adhesive polymer and a second plasticizer.
  19. 19 . The separator according to claim 18 , wherein average particle size of the adhesive polymer is 0.5 μm-3.0 μm, optionally 0.8 μm-2.0 μm.
  20. 20 . The separator according to claim 18 , wherein DSC melting point of the pressure-sensitive adhesive polymer is −50° C.-100° C., optionally −45° C.-60° C.

Description

CROSS REFERENCE TO RELATED APPLICATION The present application is a continuation of International Patent Application No. PCT/CN2023/079397, filed on Mar. 2, 2023, which claims priority to International Patent Application No. PCT/CN2022/083171, filed on Mar. 25, 2022, and also claims priority to International Patent Application No. PCT/CN2022/144349, filed on Dec. 30, 2022, the contents of which are incorporated herein by reference. TECHNICAL FIELD This application pertains to the technical field of secondary batteries, and specifically relates to a separator and a preparation method therefor, a battery, and an electric apparatus. BACKGROUND In the process of manufacturing cells of electrochemical devices, displacement of the electrode plates and separator during a transfer process is inevitable. Minor displacement can cause the electrode plates to contact each other, resulting in the scrapping of dry cells. Severe displacement can cause the electrode plates to wrinkle after full charge, significantly affecting the kinetic performance and degrading the safety performance of the cell. Therefore, an adhesive coating is currently applied to the separator, and during the first composite process of the electrode plates and separator of the electrochemical device, pre-pressing is usually performed under appropriate pressure to ensure that the electrode plates and separator of the electrochemical device have some adhesion before entering the next process. However, due to production efficiency requirements, the pressure and acting duration at this stage cannot fully meet the needs for the electrode plates and separator of the electrochemical device to achieve appropriate adhesion. SUMMARY In view of the technical issue existing in the background technology, this application provides a separator, aiming to meet the need for the electrode plates and separator of an electrochemical device to achieve appropriate adhesion under different pressures. To achieve the above purpose, a first aspect of this application provides a separator including a substrate and a pressure-sensitive coating, where the pressure-sensitive coating is formed on at least a portion of surface of the substrate, and the pressure-sensitive coating includes composite particles and a first plasticizer, the composite particles form bulges on surface of the pressure-sensitive coating, and the composite particles include polyacrylate particles and inorganic particles, where the inorganic particle is present between at least two of the polyacrylate particles, and solubility parameter of the first plasticizer and solubility parameter of the composite particles have a difference with an absolute value of 0.3 MPa1/2-4 MPa1/2. Compared with the prior art, this application has the following beneficial effects: the separator has good pressure sensitivity and compressive modulus. Its adhesion force is below 0.1 N/m at ≤1 MPa, thus avoiding adhesion between layers of the separator during roll winding and storage. At ≥2 MPa pressure, the separator can exhibit significant adhesion to the electrode plates, and thus when the separator is used to prepare a cell, the electrode plates and the separator can be tightly bonded under appropriate pressure at room temperature, thereby improving the kinetic performance of the cell. In some embodiments of this application, the first plasticizer includes an ester compound, and solubility parameter of the ester compound is 12 MPa1/2-30 MPa1/2. Thus, the solubility of the composite particles can be reduced while the pressure sensitivity of the pressure-sensitive coating is improved. In some embodiments of this application, the pressure-sensitive coating further includes an emulsifier, the emulsifier including at least one of an anionic emulsifier and a nonionic emulsifier. This facilitates the uniform distribution of the first plasticizer in the composite particles, further improving the yield rate of separator production and the pressure sensitivity of the separator. In some embodiments of this application, the pressure-sensitive coating includes 80-96 parts by weight of composite particles, 5-30 parts by weight of ester compound, and 0.1-0.5 parts by weight of emulsifier. Thus, the separator has good pressure sensitivity, thereby improving the kinetic performance of the cell. In some embodiments of this application, Dv50 of the composite particles is ≥2.5 μm, preferably 2.5 μm-10 μm, and more preferably 3 μm-8 μm. This helps form a bulge structure on the surface of the pressure-sensitive coating, thereby improving the kinetic performance of the cell. In some embodiments of this application, the composite particles include a first agglomerate, and the first agglomerate includes at least two of the inorganic particles. Thus, the kinetic performance of the cell can be improved. In some embodiments of this application, 0.01 μm≤Dv50 of the first agglomerate ≤Dv10 of the composite particles. Thus, the compressive modulus of the separat