Method for preparing heat-resistant liquid-holding lithium battery diaphragm

Abstract

The invention discloses a method for preparing a heat-resistant liquid-holding lithium battery diaphragm and belongs to the technical field of lithium battery preparation. The battery diaphragm is mainly composed of aluminium oxide and silicon dioxide, the melting points of which are both above 1000 DEG C, the produced heat and the increased temperature are low during battery charging and discharging and the pore structure of the battery diaphragm is not influenced by high temperature expansion, so that the battery diaphragm has strong heat resistance; a shorter channel can be provided for ionconduction and the ion resistance is reduced by utilizing an aluminium oxide membrane with high porosity and a through-pore structure in the lithium battery diaphragm, so that the electrochemical performance is improved; and calcium lignosulfonate and acrylamide are grafted to obtain a graft copolymer and the graft copolymer is modified by dimethylamine and formaldehyde and reacted with N-vinyl pyrrolidone to obtain an amphoteric graft copolymer which can serve as an organic hygroscopic material to improve the wettability of the battery diaphragm to an electrolyte, so that the liquid absorption rate and the liquid-holding rate of a lithium battery are increased; and therefore, the lithium battery diaphragm has a broad application prospect.

Description

technical field [0001] The invention discloses a preparation method of a heat-resistant liquid-retaining lithium battery separator, belonging to the technical field of lithium battery preparation. Background technique [0002] In the structure of lithium batteries, the separator is one of the key inner 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. A separator with excellent performance plays an important role in improving the overall performance of the battery. The main function of the diaphragm is to separate the positive and negative electrodes of the battery, prevent the two electrodes from contacting and short circuit, and also have the function of allowing electrolyte ions to pass through. The separator material is non-conductive, and its physical and chemical properties have a great influence on the performance of ...

AI Technical Summary

Problems solved by technology

[0005] The technical problem mainly solved by the present invention is that the current lithium-ion battery has been gradually expanded to the field of electric bicycles and electric vehicles, and is developing in the direction of high power and high current. The working temperature of the diaphragm of the lithium-ion battery is also increased, and the diaphragm is easily Under the action of thermal expansion and contraction, the electrical insulation nanoparticles in the coating are peeled off, and the microporous structure of the separator is blocked under the high temperature working environment, which leads to the obstruction of ions passing through the separator, which will further increase the working temperature of the battery, thereby accelerating the lithium battery. The damage of the ion battery will eventually reduce the service life of the battery, and most of the lithium battery separators are polyolefin materials, which are non-polar and have poor wettability to water and electrolyte, which seriously affects their absorption of electrolyte. efficiency, liquid retention rate and ion conductivity and other electrochemical performance defects, and provides a preparation method of heat-resistant liquid retention type lithium battery separator