Preparation method of ternary positive electrode slurry

Abstract

The invention belongs to the technical field of lithium ion batteries, and particularly relates to a preparation method of ternary positive electrode slurry. The preparation method of the ternary positive electrode slurry comprises the following steps: 1) adding a positive electrode active substance, a conductive agent and a binder into a VC efficient mixer, and carrying out mixing and sieving twice to obtain dry powder; 2) adding the dry powder into a stirrer, adding part of a solvent, standing for 20-30 minutes under the vacuum condition of -0.080 MPa to -0.085 MPa, and starting the stirrerfor stirring; 3) adding a carbon nanotube conductive paste, and carrying out stirring in vacuum; and 4) adding the residual solvent, and continuously stirring to obtain the positive electrode slurry.The VC efficient mixer is used for mixing and sieving twice, the mixing efficiency is effectively improved, moisture absorption of slurry in the slurry mixing process is inhibited through vacuum standing, agglomeration is reduced, mixing and dispersion of micron-sized particles in the slurry are facilitated, the internal resistance of the battery is reduced, and the rate capability, the cycle performance and the safety performance of the lithium ion battery are improved.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a preparation method of a ternary cathode slurry. Background technique [0002] Cathode materials in Li-ion batteries provide Li + , by Li + Moving back and forth between the positive and negative electrodes realizes the charge and discharge of the battery, so the positive electrode of the lithium-ion battery is very important to the battery performance. Ternary material lithium batteries have the characteristics of high specific capacity and high energy density, but they still need to be improved in terms of cycle performance and safety. [0003] In actual production, in addition to material factors, the battery preparation process also has a direct impact on the overall performance of lithium-ion batteries. Among them, the preparation of positive electrode slurry is an important link in the production process of lithium-ion batteries, and the disper...

AI Technical Summary

Problems solved by technology

Ternary material lithium battery has the characteristics of high specific capacity and high energy density, but it still needs to be improved in terms of cycle performance and safety

The ideal positive electrode slurry is evenly dispersed and has high stability, but the positive electrode slurry is a highly viscous solid-liquid phase suspension, which is prone to agglomeration during slurry mixing, resulting in a poor dispersion state, which not only affects the processing performance of the positive electrode sheet, but also Increase the internal resistance and reduce the safety performance of lithium-ion batteries

[0004] At present, in order to improve the dispersion effect of the positive electrode slurry and the processing performance of the battery, methods such as adding a dispersant, prolonging the stirring time, increasing the stirring speed, dry powder stirring, and increasing the number of feedings are generally used, but the effect is not obvious and there are some problems, such as high speed and long time Stirring causes the temperature of the slurry to rise and deteriorate, which reduces the viscosity of the colloid and affects the performance of the battery, etc.

[0005] For example, Chinese patent CN105406070B discloses a preparation method of lithium-ion battery positive electrode slurry. First, the glue solution is prepared, and then the pre-dispersed conductive agent and active material are added in stages, which solves the problem that the high specific surface area conductive agent is difficult to disperse, but The glue solution needs to be placed in vacuum for 12 hours, and the stirring time is long and the number of times is too long. The production cycle is too long, which will easily affect the stability of the slurry

The Chinese invention with the publication number CN108155341A also improves the dispersion and consistency of the slurry by applying glue first, then configuring the conductive glue and the slurry, but the stirring time in each step is too long, which makes the slurry very easy to Temperature rises and deteriorates, affecting processing performance, and it is difficult to ensure the dispersion effect of conductive agent and active material particles

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