Novel high-temperature-resisting diaphragm of lithium battery and preparation process of diaphragm

Abstract

The invention discloses a novel high-temperature-resisting diaphragm of a lithium battery and a preparation process of the diaphragm, which belong to the field of a battery diaphragm, and solve the problem in the prior art that the lithium battery diaphragm which is prepared by adopting a wet-method process is low in fuse temperature. The high-temperature-resisting diaphragm of the lithium battery is prepared by adopting a wet-method process. The diaphragm comprises an inner layer, an intermediate layer and an outer layer, wherein both the inner layer and the outer layer are prepared by adopting polyethylene and white oil as raw materials; the intermediate layer is prepared by adopting polyethylene, white oil and nanometer inorganic oxide as raw materials. The preparation process comprises the following steps of mixing, extrusion, compounding through a die head, casting, cooling and molding, bidirectional synchronous stretching, extraction, drying, transversely stretching and expanding and thermal setting. The fuse temperature of the diaphragm prepared through the process is detected to be 50 to 70 DEG C higher than that of the diaphragm with a single PE (polyethylene) component.

Description

technical field [0001] The invention belongs to the field of battery diaphragms, and in particular relates to a high-temperature-resistant lithium battery diaphragm and a preparation process thereof. Background technique [0002] The separator is one of the important raw materials of the battery. Its function is to separate the positive electrode from the negative electrode material, allow ions to pass through, and prevent electrons from passing through. The performance of the lithium battery separator determines the interface structure and internal resistance of the battery, which directly affects the capacity of the battery. Cycle and safety performance and other characteristics, the separator with excellent performance plays an important role in improving the overall performance of the battery. The main function of the diaphragm is to separate the positive and negative electrodes of the battery, prevent the two electrodes from contacting and short circuit, and also have t...

AI Technical Summary

Problems solved by technology

[0003] With the continuous development of lithium-ion batteries, especially in power vehicles and large-capacity energy storage batteries, in order to achieve high-rate and rapid discharge, higher requirements are put forward for lithium battery separators. It is hoped that the separators have higher porosity And through holes, and put forward higher requirements for high temperature resistance. In order to ensure safety, lithium battery separators usually require lower closed cell temperature and higher fusing temperature. However, lithium battery separators prepared by wet process are usually The lower closed cell temperature and fusing temperature are both low, which cannot meet the performance of high temperature resistance