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CN-122000618-A - Battery monomer, isolating film, preparation method of isolating film, battery device and electricity utilization device

CN122000618ACN 122000618 ACN122000618 ACN 122000618ACN-122000618-A

Abstract

The application discloses a battery monomer, a separation film and a preparation method thereof, a battery device and an electric device, wherein the battery monomer comprises a separation film and an electrolyte, the separation film comprises a porous base film, a coating layer arranged on at least one side of the porous base film, the coating layer comprises a polymer additive, the polymer additive comprises a first functional group and a second functional group, the first functional group comprises one or more of difluoro sulfonyl imino, bis (trifluoromethyl) sulfonyl imino, trifluoro boric acid group, hexafluorophosphoric acid group, sulfonic acid group, hexafluoroarsenic acid group, trifluoro methanesulfonic acid group, difluoro phosphoric acid group, dioxaboric acid group, difluoro oxalic acid boric acid group, difluoro dioxaphosphoric acid group, tetrafluorooxalic acid phosphoric acid group and imidazole group, and the second functional group comprises one or more of quaternary ammonium ion, pyrrolidinyl, pyrrolyl, piperidinyl, pyridyl and imidazole group. The application provides an isolating film for realizing the beneficial effects of the battery monomer, a preparation method thereof, a battery device and an electricity utilization device.

Inventors

  • CHEN CHANGYAN
  • ZHU YINGHUA
  • WANG SHIGUAN
  • FU KUAN
  • SHI SONGJUN
  • LAI YOULEI

Assignees

  • 宁德时代新能源科技股份有限公司

Dates

Publication Date
20260508
Application Date
20241101

Claims (14)

  1. 1. A battery cell is characterized by comprising a separation film and electrolyte, wherein the separation film comprises: a porous base film; A coating layer disposed on at least one side of the porous base film, the coating layer comprising a polymer additive comprising a first functional group comprising one or more of a bis (trifluoromethyl) sulfonimide, a trifluoroboric acid group, a hexafluorophosphoric acid group, a sulfonic acid group, a hexafluoroarsenic acid group, a trifluoromethanesulfonic acid group, a difluorophosphoric acid group, a dioxaboric acid group, a difluorooxalic acid boric acid group, a difluorodioxaphosphoric acid group, a tetrafluorooxalic acid phosphoric acid group, and an imidazole group, and a second functional group comprising one or more of a quaternary ammonium ion, a pyrrolidinyl group, a pyrrole group, a piperidinyl group, a pyridinyl group, and an imidazole group; in the electrolyte environment, the first functional group forms a positive potential group and the second functional group forms a negative potential group.
  2. 2. The battery cell of claim 1, wherein the coating comprises a polymer additive in an amount of 0.1% to 10% by mass based on the total mass of the coating.
  3. 3. The battery cell according to claim 1 or 2, characterized in that the coating comprises a mass content of 3 to 8% of polymer additive based on the total mass of the coating.
  4. 4. The battery cell of any one of claims 1-3, wherein the first functional group and the second functional group each comprise an imidazolyl group, and the polymer additive comprises one or more of polybenzimidazole, polyvinylimidazole, polyacetylimidazole, and an N-vinylimidazole copolymer.
  5. 5. The battery cell according to any one of claims 1 to 4, wherein the chemical formula of the polymer additive is represented by formula (a) or formula (b): Wherein R 1 、R 3 、R 5 、R 6 respectively comprises an empty, unsubstituted or halogen atom-substituted C1-C8 alkylene group, R 2 represents a first functional group, R 4 represents a second functional group, and n is a positive integer.
  6. 6. The battery cell according to any one of claims 1 to 5, wherein the polymer additive has a weight average molecular weight of 8000 to 80000, and/or, The swelling degree of the polymer additive in a mixed solvent of ethylene carbonate and methyl ethyl carbonate according to the volume ratio of 3:7 is less than or equal to 2 percent after the polymer additive is soaked for 7 days at the constant temperature of 60 ℃.
  7. 7. The battery cell according to any one of claims 1 to 6, wherein the polymer additive comprises one or more of compounds represented by formulas (1) to (15):
  8. 8. The battery cell of any one of claims 1-7, wherein the coating comprises a filler comprising one or more of boehmite, alumina, barium sulfate, magnesium oxide, magnesium hydroxide, a silicon oxide compound, tin dioxide, titanium oxide, calcium oxide, zinc oxide, zirconium oxide, yttrium oxide, nickel oxide, hafnium dioxide, cerium oxide, zirconium titanate, barium titanate, magnesium fluoride, aluminum hydroxide, barium oxide, silicon carbide, boron carbide, aluminum nitride, silicon nitride, boron nitride, calcium fluoride, barium fluoride, magnesium aluminum silicate, magnesium lithium silicate, sodium magnesium silicate, bentonite, hectorite, and Pb (Zr, ti) O 3 .
  9. 9. The battery cell of any one of claims 1-8, wherein the coating satisfies one or more of the following conditions: 1) The thickness of the coating is 0.5-5 mu m; 2) The areal density of the coating was 0.5g/m 2 ～9.5g/m 2 .
  10. 10. The battery cell according to any one of claims 1 to 9, wherein the separator has an ionic conductivity of 0.457ms/cm to 2.37ms/cm.
  11. 11. A separator for a battery cell, comprising: a porous base film; The porous base film comprises a porous base film, a coating layer, a polymer additive, a second coating layer and a third coating layer, wherein the coating layer comprises a polymer additive, the polymer additive comprises a first functional group and a second functional group, the first functional group comprises one or more of difluoro sulfonyl imino groups, bis (trifluoromethyl) sulfonyl imino groups, trifluoro boric acid groups, hexafluorophosphoric acid groups, sulfonic acid groups, hexafluoroarsenic acid groups, trifluoro methanesulfonic acid groups, difluoro phosphoric acid groups, difluoro boric acid groups, difluoro oxalic acid boric acid groups, difluoro dicarboxylic acid phosphoric acid groups, tetrafluorooxalic acid phosphoric acid groups and imidazole groups, and the second functional group comprises one or more of quaternary ammonium ions, pyrrolidinyl groups, pyrrole groups, piperidinyl groups, pyridyl groups and imidazole groups; in the electrolyte environment, the first functional group forms a positive potential group and the second functional group forms a negative potential group.
  12. 12. A method for preparing a separator for a battery cell, comprising: Providing a coating slip comprising a polymer additive, the polymer additive comprising a first functional group and a second functional group, the first functional group comprising one or more of a bis (trifluoromethyl) sulfonylimino group, trifluoroboric acid group, hexafluorophosphoric acid group, sulfonic acid group, hexafluoroarsenic acid group, trifluoromethanesulfonic acid group, difluorophosphoric acid group, dioxaboric acid group, difluorooxalic acid boric acid group, difluorodioxaphosphoric acid group, tetrafluorooxalic acid phosphoric acid group, and imidazole group, the second functional group comprising one or more of a quaternary ammonium ion, a pyrrolidinyl group, a pyrrolyl group, a piperidinyl group, a pyridinyl group, and an imidazolyl group; and coating the coating slurry on at least one side of the porous base film, and drying to obtain the isolating film.
  13. 13. A battery device comprising the battery cell according to any one of claims 1 to 10 or a battery cell formed by preparing the separator according to claim 11 or the separator produced by the production method according to claim 12.
  14. 14. An electrical device comprising the battery device of claim 13.

Description

Battery monomer, isolating film, preparation method of isolating film, battery device and electricity utilization device Technical Field The application belongs to the technical field of batteries, and particularly relates to a battery monomer, a separation film, a preparation method of the separation film, a battery device and an electric device. Background With the wider and wider application range of the battery cell, the use requirements of people on the battery cell are also increasing, for example, the requirements on the energy density and the quick charge performance of the battery cell are higher and higher. Therefore, how to make the battery cell have a higher level of fast charge performance under the premise of having a high energy density is a technical problem to be solved at present. Disclosure of Invention The application provides a battery monomer which has good dynamic performance, a separation film capable of realizing the beneficial effects of the battery monomer and a preparation method thereof, and a battery device and an electric device with the beneficial effects of the battery monomer. In a first aspect, the application provides a battery monomer comprising a separation membrane and an electrolyte, wherein the separation membrane comprises a porous base membrane, a coating layer is arranged on at least one side of the porous base membrane, the coating layer comprises a polymer additive, the polymer additive comprises one or more of a first functional group and a second functional group, the first functional group comprises one or more of a difluoro sulfonyl imino group, a bis (trifluoromethyl) sulfonyl imino group, a trifluoro boric acid group, a hexafluorophosphoric acid group, a sulfonic acid group, a hexafluoroarsenate group, a trifluoro methanesulfonic acid group, a difluoro phosphoric acid group, a oxalic acid boric acid group, a difluoro oxalic acid phosphoric acid group, a tetrafluorooxalic acid phosphoric acid group and an imidazole group, the second functional group comprises one or more of a quaternary ammonium ion, a pyrrolidinyl group, a pyrrolyl group, a piperidinyl group, a pyridinyl group and an imidazole group, and in the electrolyte environment, the first functional group forms a positive potential group, and the second functional group forms a negative potential group. In the embodiment of the application, the first functional group and the second functional group contained in the polymer additive in the coating of the isolating film have electron sites and electron receiving sites, and the first functional group and the second functional group can form a unique double-channel transmission mechanism in the coating of the isolating film, so that a rapid channel is provided for active ions to pass through the isolating film, the ion conductivity of the isolating film is improved, the active ion transmission rate is enhanced, the transmission resistance of the active ions in the battery monomer is reduced, and the rapid charging performance of the battery monomer is improved. In addition, the first functional group and the second functional group in the polymer additive can have certain selectivity on the transmitted metal ions, reduce the passing rate of ions of side reaction, reduce side reaction of a negative electrode interface, form a denser SEI film and improve the cycling stability of the battery monomer. In some alternative embodiments, the coating comprises a mass content of the polymer additive of 0.1% to 10%, alternatively 3% to 8%, based on the total mass of the coating. The mass content of the polymer additive in the coating is within the range, and the polymer additive can be well bonded with other components in the coating and the porous base film, so that the battery cell has good quick charge performance and high energy density. In some alternative embodiments, the first and second functional groups each comprise an imidazolyl group, and the polymer additive comprises one or more of polybenzimidazole, polyvinylimidazole, polyacetylimidazole, and an N-vinylimidazole copolymer. In the embodiment of the application, the first functional group and the second functional group on the coating of the isolating film respectively comprise imidazolyl, so that the coating has a unique double-channel transmission mechanism, has sites for providing electrons and sites for receiving electrons, is beneficial to improving the transmission efficiency of active ions and improves the dynamic performance of the battery monomer. The analysis is that the two opposite potential types are arranged on the two sides of the imidazole ring, namely the first functional group and the second functional group respectively comprise imidazole groups, the specific structure shows a double-channel ion transfer mechanism, the existence of lone pair electrons on (-N=) is favorable for strong coordination with lithium ions, so that dissociation of the lithium ions and lithium salts is promo