Detection method for pore size and pore size distribution of diaphragm

Abstract

The invention discloses a detection method for pore sizes and pore size distribution of a diaphragm. The method comprises the following steps: a visible spectrophotometer is used for scanning the diaphragm in a range set from 300m to 900nm, and the visible spectrophotometer is capable of automatically scanning from the small wavelength to the maximum wavelength and generating a curve; seen from the curve, the light transmittance is about 47-49 at the 900nm of the wavelength to indicate that the average pore size of the diaphragm is 27mm and the pore sizes are distributed quite evenly; if the light transmittance is 41-42, the average pore size of the diaphragm is greater than 30mm and the pore sizes are distributed not evenly. The method is simple to operate, but the results are quite precise; no sample needs to be prepared and the detection time is short; no other chemical material and reagent are needed, and therefore, no potential chemical injury can be caused to the operator.

Description

technical field [0001] The invention relates to the field, and more specifically relates to a method for detecting the pore size and distribution of a diaphragm. Background technique [0002] The battery separator refers to the PP or PE or composite polymer film between the positive and negative electrodes of the lithium-ion battery. Its main function is: to allow the ions in the electrolyte to pass freely between the positive and negative electrodes; to prevent the direct contact of the electrode particles; at the same time, some electrode surface processes are treated with residual dust to avoid micro-short circuits caused by these dusts. The average particle size of the electrode particles currently used is on the order of 10 microns, and the used conductive additive is on the order of 10 nanometers, but the conductive agent particles tend to agglomerate to form large particles. Therefore, to detect the size of the diaphragm hole, there should not be too large a hole. ...

AI Technical Summary

Problems solved by technology

[0004] There are two methods for testing whether the size and distribution of the existing membrane pores are uniform: one is to check the pore size and distribution through the enlarged photo of the test membrane, which has the following shortcomings: First, the detection range of the current detection method is too small (when using SEM to enlarge the photo to detect , the photo can only see the pore size and distribution in the range of a few microns), it is too partial to reflect comprehensively; second, the current detection method is time-consuming and inconvenient to operate; another method is to test the pore size and Quantitative distribution, but this method is time-consuming and somewhat dangerous due to the presence of mercury

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