Wet-process molded battery diaphragm with controllable pore diameter and preparation method thereof

Abstract

The invention provides a wet-process molded battery diaphragm with a controllable pore diameter and a preparation method thereof. The battery diaphragm is a composite diaphragm which is formed by taking a three-layered composite membrane composed of a polyolefin microporous membrane, a melted fabric and a wet-process non-woven fabric containing polyethylene staple fibers as a base material throughradiating and grafting a carboxyl or sulfonic group functional group. The wet-process molded battery diaphragm with the controllable pore diameter, provided by the invention, has the advantages of low pore closing temprature, high melting temperature, controllable pore diameter and high liquid storage rate, and has a proper ventilation function after radiation and grafting treatment; the air permeability is equal to 15 percent of a conventional non-woven fabric; the wet resistance of the battery diaphragm is low so that a discharge platform and a low-temperature property of a battery are easyto improve and foam is not generated in a utilization process; the risk that electrolyte overflows out of the battery due to the foam is not caused; compared with a conventional manner of overlappingthe plurality of membranes to use, the wet-process molded battery diaphragm is more convenient to use and dislocation and folds are not caused; the production cost is low.

Description

technical field [0001] The invention relates to the technical field of battery separators, in particular to a wet-formed battery separator with controllable pore size and a preparation method thereof. Background technique [0002] As the global energy crisis intensifies and environmental issues become more prominent, it is gradually becoming a trend for renewable energy to replace fossil fuels. The storage and use of renewable energy is inseparable from the development of chemical power sources. Among various types of chemical power systems, lithium-ion batteries have become the most popular secondary batteries because of their high voltage, high specific energy, and long life. secondary battery. At present, my country is committed to strengthening the application of lithium-ion batteries in the field of energy storage systems and new energy vehicles and other large-scale power batteries. The ultimate strategic goal of the transition from traditional power vehicles to elect...

AI Technical Summary

Problems solved by technology

However, the following problems exist in the existing diaphragm manufacturing process: (1) The porosity is difficult to control: the existing diaphragm manufacturing process is difficult to control the porosity, and the control of the pore size cannot be realized according to the actual situation, and the resistance is large, so it cannot be effective. (2) The micropores are easy to shrink: the micropores will become smaller during use, and the stability is poor; (3) The closing temperature of the micropores is high: micropores The hole needs a particularly high temperature to close, so as to prevent the passage of ions, and the safety performance of the battery cannot be guaranteed; (4) The thickness of the diaphragm is high: the thickness of the diaphragm is thick, which makes the lithium battery have low capacity and short service life; (5) Liquid storage low rate, poor wettability

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