Preparation method of high-temperature-resistant lithium ion battery composite membrane

Abstract

The invention discloses a preparation method of a high-temperature-resistant lithium ion battery composite membrane. The method comprises the following steps of adding a styrene-butadiene-styrene block copolymer into a mixed solvent of tetrahydrofuran and N,N-dimethylformamide, heating to 50-55 DEG C, and stirring for dissolving to obtain a solution A; adding polyacrylonitrile into the N,N-dimethylformamide, heating to 45-50 DEG C, stirring for dissolving to obtain a solution B, then transferring the solution A and the solution B into an injection pump, and obtaining a fiber membrane on a receiving roller by adopting an opposite spraying mode; placing the fiber membrane obtained in the step S1 in distilled water, then adding tartaric acid, heating to 90-95 DEG C, shaking for 3-5 hours, fishing out the fiber membrane, placing the fiber membrane in the distilled water again, adding nickel oxide, heating to 60-70 DEG C again, and shaking for 2-3 hours to obtain a modified fiber membrane I; and adding the modified fiber membrane I obtained in the step S2 into a dopamine aqueous solution, transferring the fiber membrane into a high-pressure reaction kettle, reacting for 1.5-3 hours at the temperature of 100-120 DEG C, performing cooling, fishing out the fiber membrane, and performing drying in a vacuum environment to obtain the composite membrane.

Description

technical field [0001] The invention belongs to the technical field of lithium-ion battery diaphragms, and in particular relates to a preparation method of a high-temperature-resistant lithium-ion battery composite diaphragm. Background technique [0002] Due to the advantages of high specific energy, long cycle life and environmental friendliness, lithium-ion batteries are widely used in portable electronic products, electric vehicles and other fields. The development of a new generation of portable electronic products and electric vehicles has put forward higher requirements for the safety and energy density of lithium-ion batteries. The separator is one of the important components of the lithium-ion battery. Its function is to prevent the physical contact between the positive and negative electrodes and provide ion conductivity by absorbing the electrolyte. Although the separator does not directly participate in the battery reaction, its structure and properties determin...

AI Technical Summary

Problems solved by technology

At present, commercialized lithium-ion battery separators mainly use polyolefin porous membranes, such as polyethylene (PE), polypropylene (PP) and their composite separators. Although they have good chemical stability and excellent mechanical properties, their Poor electrolyte affinity and thermal stability limit its application in new generation lithium-ion batteries

In order to suppress the deformation of the diaphragm at high temperature, the method of coating inorganic oxides on the diaphragm substrate is usually used to improve the thermal stability of the diaphragm. For example, in the patent CN105449141A, a polyolefin film is coated with a blend of inorganic particles and organic particles, but this When the diaphragm is too high, it still allows the lithium ions inside the battery to pass through, causing the internal temperature of the battery to continue to rise, and eventually burns or even explodes.

Images