Anti-missing blue ceramic coating film and preparation method thereof

Abstract

The invention discloses an anti-missing blue ceramic coating film and a preparation method thereof. The anti-missing blue ceramic coating film comprises a base film and a blue ceramic coating; and theblue ceramic coating is obtained by coating the surface of one side or two sides of the base membrane with a blue ceramic coating slurry and drying. Bonding between the blue ceramic coating and the base film is physical bonding and chemical bond bonding cooperation, longitudinal bonding and transverse bonding cooperation, the prepared coating film is high in shrinkage resistance, high in mechanical strength and good in soaking performance, the bonding force between the ceramic layer and the base film is good, the powder falling phenomenon is not likely to happen, and the service life of the lithium battery is greatly prolonged. The blue ceramic particles used in the invention are blue ceramic particles with the purity of more than 99.9%, and the coating slurry prepared from the ceramic particles is blue, so that the coating missing area can be quickly and conveniently identified, and the safety risk of the battery is further reduced.

Description

technical field [0001] The invention relates to the technical field of coating films, in particular to a leakage-proof blue ceramic coating film and a preparation method thereof. Background technique [0002] As the safety requirements of lithium batteries are getting higher and higher, ceramic coated diaphragms have been popularized on lithium batteries, but the conventional ceramics used at present are all white, and the color of the base film is also white, so It is difficult to find the coating defects on the ceramic coated diaphragm when the white ceramic is coated on the white base film, especially for the case of missing coating, it is even more impossible to identify visually, and the leaked diaphragm Due to the absence of the ceramic layer on the base film here, the oxidation resistance of the leak coating area is reduced, and it is more likely to be pierced by lithium dendrites, causing battery safety risks; [0003] The material of the base film is generally PP, ...

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Problems solved by technology

[0002] As the safety requirements of lithium batteries are getting higher and higher, ceramic coated diaphragms have been popularized on lithium batteries, but the conventional ceramics used at present are all white, and the color of the base film is also white, so It is difficult to find the coating defects on the ceramic coated diaphragm when the white ceramic is coated on the white base film, especially for the case of missing coating, it is even more impossible to identify visually, and the leaked diaphragm Due to the absence of the ceramic layer on the base film here, the oxidation resistance of the leak coating area is reduced, and it is more likely to be pierced by lithium dendrites, causing battery safety risks;

[0003] The material of the base film is generally PP, PE, PET and other materials. These materials are highly hydrophobic, and it is easy for the electrolyte to infiltrate the separator incompletely, causing the battery resistance to increase and forming a temperature hot spot. Once the battery temperature rises, the base film The film is easy to shrink due to heat, which will cause contact between the positive and negative electrodes of the battery and cause a short circuit. In order to avoid the above problems, people usually coat a layer of inorganic ceramic coating on the surface of the base film to improve the electrolyte of the battery coating separator. Wetting ability and high temperature resistance. Although the existing technology can improve the electrolyte wetting ability and high temperature resistance of the battery coating diaphragm, the compatibility between the base film and the inorganic ceramic coating is poor, the battery cycle degree is reduced, and it is easy to produce "Powdering" phenomenon; In order to further improve the compatibility of inorganic ceramic coatings and base films, people corona treatment is performed on the base film. Corona technology can generate free radicals on the surface of the base film to enhance the interaction between the base film and the polymer. However, many studies have pointed out that these corona-treated base films are prone to corona treatment effect decline, base film surface energy reduction, and additive components tend to decline during storage and use. The internal penetration of the base film, the decrease of the adhesion of the inorganic ceramics on the base film and other problems, the battery separator still cannot avoid the phenomenon of "powdering" in the end

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