Preparation method of high-energy-storage battery diaphragm material

Abstract

The invention discloses a preparation method of a high-energy-storage battery diaphragm material. Polyethylene maleic anhydride is grafted on and coats the surface of magnesium hydroxide, and then resin grafted, coated and modified magnesium hydroxide and matrix resin are subjected to melt blending to prepare the battery diaphragm, so that the mechanical strength, the thermal stability, the wettability, the air permeability and the safety of the diaphragm material can be improved at the same time, and the risk that an inorganic material is disengaged from the diaphragm is completely avoided. The diaphragm material is longitudinally stretched at a relatively low temperature and then longitudinally / transversely stretched synchronously at a relatively high temperature, so that the shape and the pore diameter of micropores in the diaphragm can be effectively ensured, and the micropores are prevented from being seriously deformed. Through a two-stage grafting reaction and microwave heating,grafting and coating of surface resin are carried out on magnesium hydroxide, and grafting and coating of magnesium hydroxide can be uniformly and completely realized.

Description

technical field [0001] The invention relates to the field of secondary batteries, in particular to a method for preparing a diaphragm material for a high energy storage battery. Background technique [0002] The high energy storage secondary battery is mainly composed of positive electrode, negative electrode, electrolyte and battery diaphragm. The battery diaphragm refers to a layer of diaphragm material between the positive electrode and the negative electrode of the battery. When the battery is charging and discharging, ions can freely pass through the battery diaphragm. 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 diaphragm is one of the key battery components. The performance of the diaphragm determines the interface structure and internal resistance of the battery, which directly affects the capacity...

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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