Novel kneading method and applications of cathode slurry

Abstract

The invention discloses a novel kneading method and applications of a cathode slurry. The method comprises the steps of (1) preparing cathode active substance powder, conductive agent, adhesive and solvent; (2) uniformly mixing the cathode active substance powder with the conductive agent to obtain mixed powder; (3) adding 20-40 wt% of the solvent into the mixed powder obtained in the step (2) for kneading; (4) adding the adhesive and the remnant solvent into the kneading slurry obtained in the step (3), and then performing stirred dispersion to obtain the cathode slurry. The novel kneading method of the cathode slurry greatly saves stirring time, and avoids re-accumulation of the adhesive, dispersing non-uniformity and a series of problems caused by dispersing non-uniformity due to affinity of the solvent and the conductive agent. The obtained cathode slurry is good in dispersibility and has a wide application prospect.

Description

technical field [0001] The invention belongs to the technical field of lithium ion battery manufacturing, and relates to a negative electrode slurry, its kneading method and application, in particular to a negative electrode slurry, its kneading method and its application for manufacturing lithium ion batteries. Background technique [0002] Lithium-ion batteries have the advantages of high energy density, high discharge platform, long cycle life, and no memory effect. They have been widely used in mobile phones, cameras, notebook computers and other fields. At the same time, they have also begun to be used in power batteries such as electric bicycles and electric vehicles. [0003] The preparation of slurry is a key process in the production of lithium batteries, and the uniformity of slurry mixing is directly related to the preparation process of subsequent processes and battery performance. The negative electrode slurry generally contains negative electrode active materia...

AI Technical Summary

Problems solved by technology

However, the traditional method has the following disadvantages: (1) after the dissolved binder is added to the mixed slurry composed of negative active material and conductive agent, water is firstly absorbed by the conductive agent due to the easy affinity between water and the conductive agent , while the binder separates out into agglomerates and needs to be re-dispersed, which greatly increases the difficulty of dispersion and increases the dispersion time

(2) After the binder is agglomerated, the dispersion is not complete, resulting in the blockage of the filter screen during the transfer of the slurry to the coating process, or the occurrence of large particles during the coating process, or poor sticking during rolling

(3) The dispersion of the binder is not complete, resulting in a decrease in the active material in a certain area after coating, reducing the binder in the remaining areas, and reducing the bonding strength after coating; the incomplete dispersion of the binder will also cause the negative electrode to the positive electrode to be in a negative state. The N / P ratio in the undispersed area is not enough, and there is a security risk

However, with the method of powder pre-mixing, there will be a large amount of dust flying in the early stage of slurry preparation. On the one hand, it will have undue impact on the environment and personnel, and on the other hand, the loss of powder due to dust flying will also affect the quality of the slurry. consistency

[0005] In the kneading and stirring method commonly used in the prior art, although the problem of environmental pollution caused by flying dust has been solved, the problem of uneven dispersion of the binder and the slurry caused by poor dispersion of the binder still generally exist. Problems arise during material application

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