Lithium ion battery negative plate, preparation method thereof and lithium ion battery

Abstract

The invention belongs to the technical field of lithium ion batteries, and particularly relates to a lithium ion battery negative plate. The lithium ion battery negative plate comprises a negative current collector and a negative active material layer coated on the surface of the negative current collector. The negative active material layer comprises a negative active material, a conductive agent, a dispersing agent, a binding agent and a thickening agent. The dispersing agent, the binding agent and the thickening agent are acrylic polymers of which the relative molecular masses are sequentially increased respectively. According to the invention, the dispersing agent sodium carboxymethyl cellulose, the binding agent styrene butadiene rubber and the thickening agent sodium carboxymethyl cellulose are changed into acrylic polymers with sequentially increased relative molecular mass respectively; the affinity of the negative active material layer to an electrolyte is improved, which facilitates the conduction of metal ions, and promotes the transmission of lithium ions in an electrode-electrolyte interface; the rate charge-discharge performance of the lithium ion battery is improved;besides, under a low-temperature condition, the acrylic polymers can accelerate the transmission of lithium ions by improving the affinity to the electrolyte; and the low-temperature performance of the lithium ion battery is improved.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a lithium ion battery negative plate, a preparation method thereof, and a lithium ion battery. Background technique [0002] Lithium-ion batteries have gradually conquered the application market of various energy storage batteries due to their excellent performance such as high energy density, high working voltage, and long cycle life, and have changed people's lives. The traditional 3C field has shown that the lithium-ion battery is the only one, and the emerging fields such as electric vehicles, smart grids, and distributed energy storage have provided new opportunities and challenges for the development of lithium-ion batteries. [0003] A lithium-ion battery is mainly composed of a positive electrode, a negative electrode, a separator, and an electrolyte solution between them. The positive electrode and the negative electrode include materials that c...

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Problems solved by technology

[0005] However, SBR is a small molecular linear chain emulsion, which is easily dispersed in water and polar solvents, while the lithium-ion battery electrolyte is a non-aqueous organic solvent, so the chemical structure and properties of SBR itself determine its affinity with the electrolyte It is not strong, which leads to poor liquid absorption effect of the pole piece and small liquid storage in the battery cell, which is not conducive to the rate discharge performance, low temperature charge and discharge performance and long-term cycle performance of the battery cell.