Aramid fiber resin-based microporous lithium electric diaphragm and preparation method thereof

Abstract

The invention provides an aramid fiber resin-based microporous lithium electric diaphragm and a preparation method thereof. The diaphragm comprises aramid fiber resin and a diaphragm modified material, and has a three-dimensional micro nanometer pore passage structure; the average pore diameter is adjustable in a range of 20 to 1000 nanometers; the thickness is 12 to 60 micrometers; the pore rateexceeds 50 percent; and the diaphragm shows good electrolyte affinity, high temperature resistance and mechanical intensity. The preparation method of the aramid fiber resin-based microporous lithiumelectric diaphragm comprises the following steps of (1) processing diaphragm forming raw materials; (2) preparing a diaphragm forming solution; (3) scraping a diaphragm and performing diaphragm phaseconversion hole formation; and (4) performing wet diaphragm post treatment, rolling and pressing and drying, and finally preparing a battery diaphragm. The aramid fiber resin-based microporous lithiumelectric diaphragm provided by the invention has excellent integrated performance, and is superior to the conventional coating type aramid fiber composite lithium electric diaphragm; and the obviouseffect is achieved on improving the heavy current charging and discharging performance of the battery, improving the heat safety performance of the battery and the like. The preparation method has thecharacteristics that the environment-friendly effect is realized; the cost is low; the process is simple; the continuous production is convenient, and the like.

Description

technical field [0001] The invention belongs to the field of preparation of diaphragm materials for lithium ion batteries, in particular to an aramid resin-based microporous lithium diaphragm and a preparation method thereof Background technique [0002] Lithium-ion battery is a new type of green secondary battery successfully developed in the 1990s. It has the advantages of high energy density, long cycle life, environmental friendliness, reliability, and fast charging and discharging. It is currently widely used in various digital products, and in Applications in the field of new energy are also expanding. The diaphragm is one of the core key materials of lithium-ion batteries, which mainly determines the safety and charge-discharge performance of the battery. Today, as the requirements for separators in power lithium batteries continue to increase, separators with higher safety, better electrochemical stability, better liquid absorption and better uniformity have become ...

AI Technical Summary

Problems solved by technology

Due to the poor thermal stability of the former, there will be obvious dimensional shrinkage at high temperatures above 120°C, and there will be relatively large safety hazards during battery use. The latter is coated with a layer of ceramic particles or high-temperature-resistant resin coating on the surface of polyolefin Finally, the thermal stability of the separator and the wettability of the electrolyte are improved to a certain extent, but at the same time, there are also disadvantages that the ceramic particles or resin layer fall off (powder falling) and the uniformity (pore size, pore shape) is difficult to control.

It can be seen that with the traditional polyolefin separator as the base film, it is still difficult to fundamentally improve the performance of the separator through simple coating and other modification methods, and it is still not enough to greatly improve the safety of lithium-ion batteries.

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