A kind of ternary lithium ion battery positive electrode sheet and its preparation method and battery

Abstract

The invention provides a positive electrode sheet of a ternary lithium ion battery, a preparation method thereof and the battery. The preparation method comprises: dissolving the binder in a solvent to obtain glue A; taking out part of glue A and adding part of conductive agent a to obtain slurry B; adding the remaining conductive agent a and part of glue A to the slurry In the material B, the slurry C is obtained; adding part of the conductive agent b to the slurry C to obtain the slurry D; adding the remaining conductive agent b and the remaining glue A to the slurry D to obtain the slurry E; Add the positive electrode material to the slurry E in two or three times, use a solvent to adjust the viscosity, vacuum degassing, and sieve to obtain the slurry F; coat the slurry F on the aluminum current collector, ultrasonically, dry, and hot press and baking to obtain the positive electrode sheet of the ternary lithium ion battery. The present invention also provides the positive electrode sheet obtained by the above preparation method and the battery containing it, and the battery has lower internal resistance and higher cycle performance.

Description

technical field [0001] The invention relates to a method for preparing a low-resistance high-nickel lithium-ion battery positive plate, belonging to the technical field of lithium-ion power batteries. Background technique [0002] As lithium-ion batteries are gradually applied to various fields of our lives, people have higher and higher requirements for the performance of lithium-ion batteries, and the mileage issue is the focus of attention. The improvement of the positive electrode is very important, such as improving the conductivity of the positive electrode sheet and the wettability of the electrolyte, etc., will further increase the life of the lithium-ion battery. [0003] The problems of uneven surface distribution and poor conductivity of the positive electrode sheet are mainly affected by the positive electrode preparation process. For example, the solvent mixes and coats the positive electrode active material, conductive agent and glue on the current collector. ...

AI Technical Summary

Problems solved by technology

For example, the solvent mixes and coats the positive electrode active material, conductive agent and glue on the current collector. During the drying process, the substances move and layer on the current collector due to the difference in density. The lighter conductive agent is mostly dense on the surface of the pole piece. The heavier positive active material and glue are densely concentrated in the lower layer of the pole piece, the uniformity of the pole piece material is poor, and the bonding force between the materials is poor, which will increase the internal resistance of the positive pole piece, thereby affecting the battery cycle life

[0004] Aiming at the dispersion problem of positive electrode slurry, the traditional slurry mixing process adopts methods of prolonging the stirring time, speeding up the stirring speed, increasing the feeding times or using the dry powder mixing process to improve the dispersion effect of the slurry and the processing performance of the electrode plate, but the effect is not obvious and exists Various disadvantages

For example, the temperature of the slurry will increase and deteriorate, which will affect the adhesion of the plate and ultimately affect the performance of the battery, etc.

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