Negative electrode slurry and its preparation method and application

Abstract

The invention discloses a negative electrode slurry and its preparation method and application. The method comprises: adding a negative electrode active material, a conductive agent and a thickener into a three-axis planetary mixer for mixing and stirring to obtain a first mixed material; Adding additives to the mixed material and stirring to obtain a second mixed material; adding a solvent to the second mixed material and stirring under vacuum conditions to obtain a first mixed slurry with a solid content of 80wt% to 90wt%; adding to the first mixed slurry Add a solvent to the material and continue to stir under vacuum conditions to obtain a second mixed slurry with a solid content of 60wt% to 72wt%; add a binder and a solvent to the second mixed slurry and continue to stir under vacuum conditions to obtain A third mixed slurry with a solid content of 53wt%-58wt%, adding a solvent to the third mixed slurry and continuing to stir under vacuum to obtain a negative electrode slurry with a viscosity of 3000-8000mPa·s. The method can effectively solve the infiltration problem of the negative electrode active material and the solvent at the initial stage of stirring, shorten the stirring time of the slurry, and improve the viscosity consistency of the slurry.

Description

technical field [0001] The invention belongs to the field of lithium ion batteries, in particular, the invention relates to negative electrode slurry and its preparation method and application. Background technique [0002] In order to meet the needs of the domestic power lithium battery market, major lithium battery manufacturers continue to optimize the lithium battery technology. The homogenization and mixing process is an important process of lithium battery production in the lithium battery industry, accounting for 30% of the process, and plays a decisive role. The quality of the slurry mixing determines the later coating and the performance of the final lithium battery. [0003] At present, the negative (anode) electrodes of mainstream lithium battery enterprises at home and abroad mainly use copper foil as the current collector and graphite system as the active material. As another key manufacturing process of lithium-ion batteries, the coating process is currently a...

AI Technical Summary

Problems solved by technology

[0004] In order to solve the problem of poor appearance and high efficiency of the negative electrode coating, there are currently two main solutions to the mixing process: the first is to improve the dispersion of the negative electrode slurry, such as high-speed dispersion, kneading and stirring, and other batching processes. High-speed dispersion not only Stirring time is long, energy consumption is high, and it has a certain destructive effect on organic polymers such as stabilizers and binders in the formula, thereby affecting the stability of the slurry and the adhesion of the pole piece; For mixers, because the torque force of the revolving paddle is not strong enough, there is a requirement for the solid content of kneading. If the solid content is too high, the viscous resistance will be too large, which will cause the revolving paddle to fail to rotate.

The second is to change the composition of the negative electrode slurry. The components that can be added will often remain in the electrode sheet, which will affect the performance of the battery cell. At the same time, the improvement effect is unstable and needs to be repeated.

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