Polymer composite film and preparation method thereof, and lithium ion battery comprising polymer composite film

Abstract

The invention discloses a polymer composite film and a preparation method thereof, and a lithium ion battery comprising the polymer composite film. The polymer composite film comprises a polymer basefilm, which comprises a first surface and a second surface, wherein the first surface and the second surface are oppositely arranged, the polymer composite film further comprises a first ceramic layer, a first heat-resistant fiber layer and a first adhesion layer, the first ceramic layer, the first heat-resistant fiber layer and the first adhesion layer are sequentially arranged on the first surface of the polymer base film from inside to outside, the materials of the first heat-resistant fiber layer simultaneously contain a first macromolecule material and a second macromolecule material, thefirst macromolecule material is a heat-resistant macromolecule material with a melting point of more than 180 DEG C, the melting point of the second macromolecule material is lower than the melting point of the first macromolecule material, the liquid absorption rate of the second macromolecule material in a 25 DEG C electrolyte is more than 40%, and the error is + / -5%. According to the present invention, by simultaneously using the first macromolecule material and the second macromolecule material, the high temperature stability and the mechanical property under the high temperature condition can be easily improved.

Description

technical field [0001] The invention relates to the field of lithium ion batteries, in particular to a polymer composite membrane and a preparation method thereof; the invention also includes a lithium ion battery using the aforementioned polymer composite membrane. Background technique [0002] Lithium-ion batteries are mainly composed of positive / negative electrode materials, electrolytes, separators and battery casing packaging materials. The separator is an important part of the lithium-ion battery, which is used to separate the positive and negative electrodes and prevent the internal short circuit of the battery; it allows the electrolyte ions to pass freely to complete the electrochemical charge and discharge process. Its performance determines the interface structure and internal resistance of the battery, which directly affects the rate performance, cycle performance and safety performance (high temperature resistance) of the battery. The separator with excellent pe...

AI Technical Summary

Problems solved by technology

[0004] However, although the separator prepared by the "melt stretching method" is relatively low in cost and relatively good in mechanical strength (toughness and strength), its high temperature resistance stability (thermal shrinkage) is not good; Although the high-temperature stability of the separator prepared by the method has been improved, its cost is relatively high, and the mechanical strength of the material is deteriorated (hardened), which limits its development in the battery field.

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