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CN-122000622-A - Coating diaphragm, preparation method thereof and battery

CN122000622ACN 122000622 ACN122000622 ACN 122000622ACN-122000622-A

Abstract

The invention relates to the technical field of batteries, and provides a coating diaphragm, a preparation method thereof and a battery, wherein the coating diaphragm comprises a base film and a coating arranged on at least one surface of the base film, and the coating comprises the following raw materials, by weight, 1-1.5 parts of hydroxylated epoxy resin, 2.8-3.3 parts of emulsion type binder and 15-20 parts of filler. Through the technical scheme, the problem that the coating diaphragm in the related technology is difficult to meet the requirements of the high-safety battery on the heat resistance, the high peel strength and the low-moisture content comprehensive performance of the diaphragm at the same time is solved.

Inventors

  • BAI ZIHANG
  • YUAN HAICHAO
  • XU FENG
  • Su bihai
  • TIAN HAILONG
  • XING PENG

Assignees

  • 河北金力新能源科技有限公司

Dates

Publication Date
20260508
Application Date
20251229

Claims (10)

  1. 1. The coated diaphragm is characterized by comprising a base film and a coating layer arranged on at least one surface of the base film, wherein the coating layer comprises, by weight, 1-1.5 parts of hydroxylated epoxy resin, 2.8-3.3 parts of emulsion-type binders and 15-20 parts of fillers.
  2. 2. The coated separator of claim 1, wherein the hydroxyl content of the hydroxylated epoxy resin is 1.2 to 1.5mmol/g.
  3. 3. The coated membrane according to claim 1, wherein the coating further comprises the following raw materials, by weight, 0.3-0.6 parts of a dispersing agent and 0.015-0.03 parts of a wetting agent.
  4. 4. A coated separator according to claim 1, wherein the emulsion type binder comprises one or more of an acrylate emulsion, a polyurethane emulsion, a fluoropolymer emulsion, and/or The filler comprises one or more of alumina, boehmite, aluminum nitride, aluminum hydroxide, and solid electrolyte.
  5. 5. The coated separator of any of claims 1-4, wherein the hydroxylated epoxy resin is a siloxane group grafted hydroxylated epoxy resin.
  6. 6. The coated membrane according to claim 5, wherein the raw materials of the siloxane group grafted hydroxylated epoxy resin comprise, by weight, 100-105 parts of hydroxylated epoxy resin and 20-30 parts of silane coupling agent.
  7. 7. A method for preparing the coated membrane according to any one of claims 1 to 4, comprising the steps of: S1, providing raw materials required by a coating; S2, mixing and grinding the raw materials to obtain coating slurry; S3, coating the coating slurry on at least one surface of a base film, and drying to obtain a coating diaphragm to be crosslinked; S4, dip-coating the coating diaphragm to be crosslinked in a solution containing an initiator, and crosslinking to obtain the coating diaphragm.
  8. 8. The method for preparing the coated membrane according to claim 7, wherein the step S1 comprises the steps of dissolving epoxy resin in ethanol, adding boron trifluoride diethyl etherate, ring-opening reaction, and distilling under reduced pressure to obtain the hydroxylated epoxy resin.
  9. 9. The preparation method of the coating diaphragm according to claim 8, wherein the step S1 further comprises grafting the hydroxylated epoxy resin with siloxane groups, and the preparation method comprises the steps of mixing the hydroxylated epoxy resin with toluene, hydroquinone, a silane coupling agent and dibutyltin dilaurate, and carrying out reflux reaction to obtain the hydroxylated epoxy resin grafted with siloxane groups.
  10. 10. The battery is characterized by comprising the coating diaphragm according to any one of claims 1-6 or the coating diaphragm prepared by the preparation method according to any one of claims 7-9.

Description

Coating diaphragm, preparation method thereof and battery Technical Field The invention relates to the technical field of batteries, in particular to a coating diaphragm, a preparation method thereof and a battery. Background With the development of new energy industry, batteries are widely used in the fields of electric automobiles, energy storage systems and the like. The market places higher demands on the energy density, cycle life and safety of batteries. The separator serves as a key inner layer component of the battery, and the performance of the separator directly influences the overall performance and safety performance of the battery. In order to improve the heat resistance of the separator, a technical scheme of coating a heat-resistant coating on the surface of a polyolefin-based film is generally adopted in the industry. The coating is mainly composed of heat-resistant inorganic particles (such as alumina and boehmite), can maintain the structural integrity of the diaphragm at high temperature and delay heat shrinkage. However, although the conventional heat-resistant coating improves the heat resistance, other performances are difficult to be considered, namely, on one hand, the peeling strength between the coating and the base film is low, the coating is easy to fall off in battery assembly or long-term circulation to cause internal short circuit risk, and on the other hand, moisture is easy to be introduced in the preparation process of the coating, so that the water content of the diaphragm is high, the stability of an electrolyte and an electrode interface is damaged, and the performance degradation of the battery is accelerated. Therefore, although the heat stability of the separator is improved to a certain extent by the existing heat-resistant coating technology, the heat resistance, the high peel strength and the low moisture content of the separator are often sacrificed at the cost of increasing the moisture content of the separator, and the comprehensive performance requirements of the high-safety battery on the heat resistance, the high peel strength and the low moisture content of the separator are difficult to meet. Disclosure of Invention The present invention is directed to a coated separator, a method of preparing the same, and a battery that solve or at least mitigate one or more of the above-mentioned problems and other problems of the prior art. The technical scheme of the invention is as follows: The invention provides a coating diaphragm which comprises a base film and a coating arranged on at least one surface of the base film, wherein the coating comprises, by weight, 1-1.5 parts of hydroxylated epoxy resin, 2.8-3.3 parts of emulsion-type binders and 15-20 parts of fillers. As a further technical scheme, the hydroxyl content of the hydroxylated epoxy resin is 1.2-1.5 mmol/g. As a further technical scheme, the coating also comprises the following raw materials, by weight, 0.3-0.6 part of a dispersing agent and 0.015-0.03 part of a wetting agent. As a further technical scheme, the emulsion type adhesive comprises one or more of acrylate emulsion, polyurethane emulsion and fluoropolymer emulsion, and/or The filler comprises one or more of alumina, boehmite, aluminum nitride, aluminum hydroxide, and solid electrolyte. As a further technical scheme, the hydroxylated epoxy resin is a siloxane group grafted hydroxylated epoxy resin. The raw materials of the siloxane group grafted hydroxylated epoxy resin comprise, by weight, 100-105 parts of hydroxylated epoxy resin and 20-30 parts of silane coupling agent. The invention also provides a preparation method of the coating diaphragm, which is used for preparing the coating diaphragm and comprises the following steps: S1, providing raw materials required by a coating; S2, mixing and grinding the raw materials to obtain coating slurry; S3, coating the coating slurry on at least one surface of a base film, and drying to obtain a coating diaphragm to be crosslinked; S4, dip-coating the coating diaphragm to be crosslinked in a solution containing an initiator, and crosslinking to obtain the coating diaphragm. As a further technical scheme, the preparation method of the hydroxylated epoxy resin comprises the steps of dissolving the epoxy resin in ethanol, adding boron trifluoride diethyl etherate, carrying out ring opening reaction, and carrying out reduced pressure distillation to obtain the hydroxylated epoxy resin. As a further technical scheme, the step S1 also comprises the step of grafting the hydroxylated epoxy resin by using siloxane groups, and the specific method comprises the steps of mixing the hydroxylated epoxy resin with toluene, hydroquinone, a silane coupling agent and dibutyltin dilaurate, and carrying out reflux reaction to obtain the hydroxylated epoxy resin grafted by the siloxane groups. The invention also provides a battery, which comprises the coating diaphragm or the coating diaphragm prepared by the preparation