PDVF coating method for battery separator

Abstract

The invention discloses a PDVF coating method for a battery separator and aims at providing a PDVF coating method for a battery separator with the advantages of reducing a barrier of a coating layer to ion permeation and improving the energy density of a battery on the premise of not affecting surface modification of the separator. According to the main points of the technical scheme, atomized droplets with PVDF particles are sprayed on the surface of a base layer of the battery separator or coat the surface in a spinning manner, the atomized droplets are dried to form a plurality of point sediments and a modified layer is formed. According to the PDVF coating method, the interaction between a coating and the separator can be reduced and the resistance when ions migrate on the interface isreduced. Improvement of the conductivity of the battery is facilitated, the influence of the modified layer on the charge-discharge performance of the battery is reduced, meanwhile, the influence ofa gel layer on the ionic conductivity is reduced, the time of balancing liquid absorption of the modified layer and of the separator is shortened and the whole conductivity of the battery is improvedto improve the performance of the separator and the battery.

Description

technical field [0001] The invention relates to the field of battery diaphragm manufacturing methods, in particular to a PDVF coating method for a battery diaphragm. Background technique [0002] The battery diaphragm refers to a layer of diaphragm material between the positive and negative electrodes of the battery. It is a very critical part of the battery and has a direct impact on battery safety and cost. Its main function is to isolate the positive and negative electrodes and prevent the electrons in the battery from Freely pass through, allowing the ions in the electrolyte to pass freely between the positive and negative electrodes. [0003] The ion conductivity of the battery separator is directly related to the overall performance of the battery. Its function of isolating the positive and negative electrodes enables the battery to limit the increase in current when the battery is overcharged or the temperature rises, preventing the battery from short-circuiting and c...

AI Technical Summary

Problems solved by technology

This modified layer densely coated on the surface of the separator can play a role in modification to a certain extent, but there are still many problems: first, the gel layer is often formed after the modified layer absorbs the electrolyte, and The ionic conductivity of the adhesive layer is significantly lower than that of the electrolyte, which results in a longer time for the modified diaphragm to absorb liquid and a decrease in conductivity.

[0009] Second, the weak interaction between the coating layer and the separator increases the resistance of ions to migrate at this interface, which is not conducive to the improvement of electrical conductivity, and affects the charge and discharge performance of the battery, reducing the energy density of the battery.

Images