Method for rapidly evaluating crystal points of hard elastic diaphragm of homo-polypropylene lithium battery

Abstract

The invention belongs to the field of polymer resin evaluation, and relates to a method for evaluating crystal points of a hard elastic diaphragm of a homo-polypropylene lithium battery. The method comprises the following steps that: a special material for a lithium battery diaphragm is extruded and cast through casting rollers by utilizing a double-screw extruder; before the hard elastic diaphragm is wound, an online defect detector is installed in advance at the position after extrusion machining is completed; and before traction winding, a cast diaphragm is subjected to multi-layer winding and extension, and then is stretched and flattened between the last two groups of cast rollers to form a hard elastic diaphragm, lithium battery hard elastic diaphragm crystal point detection is carried out through the online defect detector, crystal point data is collected, and the product quality is estimated according to a crystal point classified collection quantity. According to the method, the relation between product crystal points, ash content, a rebound rate and filter screen permeability is obtained through the online defect detector, and therefore, the product evaluation time is shortened, the performance of the special material for the lithium battery diaphragm can be preliminarily judged in the process of preparing the lithium battery hard elastic diaphragm, and the evaluation efficiency is greatly improved.

Description

technical field [0001] The invention relates to the field of polymer resin evaluation, in particular to a method for evaluating the crystal point of a homopolypropylene lithium battery rigid elastic diaphragm. [0002] technical background [0003] The polymer changes from a solid raw material to a melt, and then from a melt to a solid sheet and film, that is, a series of phase changes occur during the processing of the material. [0004] In the production process of homopolypropylene lithium battery film, due to raw materials, equipment, processing parameters and other reasons, there will be many appearance problems, such as crystal points, white spots, fish eyes, horizontal stripes, mottling, undrawn Stretch marks, etc. Even if the fineness of the filter screen of the extruder is increased, the large crystal points on the film can be reduced to a certain extent, but the small crystal points will still pass through the filter screen, which will increase the pressure of the ...

AI Technical Summary

Problems solved by technology

Even if the fineness of the filter screen of the extruder is increased, the large crystal points on the film can be reduced to a certain extent, but the small crystal points will still pass through the filter screen, which will increase the pressure of the filter and increase the frequency and cost of replacing the filter screen.

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