Slurry dispersion system, negative electrode slurry and lithium ion battery

Abstract

The invention belongs to the field of batteries, and particularly relates to a novel slurry dispersion system, a negative electrode slurry and a lithium ion battery. The novel slurry dispersion systemcomprises a conductive agent, a solvent and an additive. The additive contains aromatic rings, and the number of rings contained in the aromatic rings is 1-3. The invention further provides the negative electrode slurry containing the novel slurry dispersion system and an active material, and provides the lithium ion battery, the lithium ion battery comprises a positive electrode, a negative electrode, an electrolyte and an isolation membrane, the negative electrode comprises a negative electrode membrane and a current collector, and the negative electrode membrane is formed by coating the negative electrode slurry on the current collector. By adopting the slurry dispersion system provided by the invention, dispersity, a rheological property, uniformity and stability of the negative electrode slurry are improved so that the negative electrode slurry has uniform conductivity and proper viscosity, and a first effect and cycle performance of the lithium ion battery are improved.

Description

technical field [0001] The invention belongs to the field of batteries, and more specifically relates to a novel slurry dispersion system, negative electrode slurry and lithium ion batteries. Background technique [0002] Power batteries are the core of the new energy vehicle industry. Battery slurry is the most critical factor in the entire battery pole piece preparation process. The battery slurry is formed by uniformly dispersing active materials, binders, and conductive agents in a solvent through stirring, and belongs to a typical high-viscosity solid-liquid two-phase suspension system. [0003] Lithium-ion battery negative electrode slurry must be uniform and stable. Negative electrode slurry materials include: active material, binder, conductive carbon and dispersant. The particle size of this series of materials is different, and the surface energy is also different. During the preparation process of the negative electrode slurry, the problem of uneven dispersion o...

AI Technical Summary

Problems solved by technology

During the preparation process of the negative electrode slurry, the problem of uneven dispersion of the slurry often occurs, which leads to a significant increase in the particle size of the slurry, which in turn causes the negative electrode slurry to block the filter element and scratches on the coating particles, coating broken belt, cold pressing Poor appearance, low yield and other problems, more serious may also lead to the deterioration of electrical conductivity and the consequences of cyclic lithium analysis

[0004] At present, in order to solve the problem of uneven dispersion of negative electrode slurry, there are usually the following approaches: (1) increase the rotating speed of the dispersion plate in the stirring tank. This method may improve the dispersion of the slurry to a certain extent, but the mechanical shear of the stirring paddle The shear force makes the slurry viscosity of the pseudoplastic rapidly decrease, resulting in a decrease in the stability of the slurry and defects in coating

In addition, this solution does not significantly improve the problem of large particles of slurry; (2) modify the surface of graphite, the negative active material, through surface modification, the graphite surface can be grafted with polar functional groups to improve the wetting of graphite and water This method can effectively improve the dispersion of the slurry, but because the modified graphite will increase the cost of the battery objectively, its application range is narrow

Images