A kind of preparation method of high energy storage battery diaphragm material

Abstract

The invention discloses a preparation method of a diaphragm material for a high energy storage battery. The surface of magnesium hydroxide is grafted and coated with polyethylene maleic anhydride, and then the resin graft coated modified magnesium hydroxide and matrix resin are melt blended. Made into a battery separator, it can simultaneously improve the mechanical strength, thermal stability, wettability, gas permeability, and safety of the separator material and completely avoid the risk of de-embedding of inorganic materials from the separator. The diaphragm material is first stretched longitudinally at a lower temperature, and then stretched longitudinally / transversely at a relatively high temperature, which can effectively ensure the shape and diameter of the micropores on the diaphragm, and the micropores will not be severely deformed. Through two-stage grafting reaction and microwave heating, the resin graft coating on the surface of magnesium hydroxide can realize the graft coating of magnesium hydroxide uniformly and completely.

Description

technical field [0001] The invention relates to the field of secondary batteries, in particular to a preparation method of a separator material for high energy storage batteries. Background technique [0002] The high energy storage secondary battery is mainly composed of positive electrode, negative electrode, electrolyte and battery separator. The battery separator refers to a layer of separator material between the positive electrode and the negative electrode of the battery. Electrons cannot pass through, and the battery separator can avoid short circuits caused by direct contact between the positive and negative electrodes of the battery. For high energy storage secondary batteries, the separator is one of the key battery components. The performance of the separator determines the interface structure and internal resistance of the battery, which directly affects the capacity, cycle and safety performance of the battery. The separator plays an important role in improvin...

AI Technical Summary

Problems solved by technology

Although polyolefin microporous membranes have been commercially produced, due to the nature of polyolefin itself, polyolefin microporous membranes have problems such as low mechanical strength and poor wettability, and once the battery is overheated, the microporous membrane Shrinkage and deformation will occur, causing the positive electrode material and the negative electrode material to contact and short circuit occurs. Once the battery short circuit occurs, it is easy to ignite the surrounding combustibles and cause a fire disaster.

The existing methods of modifying polyolefin microporous membranes with inorganic materials mostly use inorganic materials to coat the surface of microporous membranes, and a few use inorganic materials to blend with microporous membrane matrix materials to form membranes, but there are inevitably The problem of deintercalation of inorganic materials and difficulty in uniform dispersion, deintercalation of inorganic materials will cause pollution and damage to the battery itself, and agglomeration will lead to a decrease in the performance of the separator in all aspects

The existing methods of modifying microporous membranes with inorganic materials can only improve a certain aspect of the performance of the membrane, such as thermal stability, and it is difficult to simultaneously improve the performance of the membrane such as mechanical strength, thermal stability, and wetting through a single modification method. Comprehensive improvement in performance, breathability, safety, etc.

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