Negative plate and lithium ion battery comprising the same

Abstract

The invention provides a negative plate and a lithium ion battery comprising the same. A first negative active material layer in the negative plate is arranged on a bottom layer and comprises a firstbinder resistant to electrolyte swelling, a chemical corrosion resistance effect is better, aging is not prone to happening, long-acting bonding between the bottom layer of active materials and a current collector is guaranteed, and battery cell expansion under quick charging is reduced. The negative plate disclosed by the invention can maintain good mechanical strength and ductility under the soaking of an electrolyte, and ensures that the negative active material layer is not separated from a negative current collector; and a second binder in a second negative active material layer far awayfrom the negative current collector selects a high-swelling material with a solubility parameter similar to that of the electrolyte, the affinity of the high-swelling binder and the electrolyte is better, the infiltration speed of the electrolyte is good, lithium ion conduction is facilitated, and meanwhile, the high-swelling binder is better bonded with a diaphragm in the hot pressing process sothat an interface bonding effect between the negative electrode active material layer and the diaphragm is improved.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a negative electrode sheet and a lithium ion battery including the negative electrode sheet. Background technique [0002] In recent years, with the increasing popularity of new energy vehicles and the rapid development of electronic devices such as notebook computers and smart phones, the development and progress of lithium-ion battery technology as the core of energy supply has been driven, and more and more advanced lithium-ion battery technology has been proposed. There are higher requirements, such as higher energy density, faster charging and discharging speed, better battery life and more relaxed use environment. [0003] Under the fast charging system, without sacrificing energy density, the requirements for the negative electrode charging capacity of lithium-ion batteries are getting higher and higher. During the fast charging process, the negat...

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Problems solved by technology

[0003] Under the fast charging system, without sacrificing energy density, the requirements for the negative electrode charging capacity of lithium-ion batteries are getting higher and higher. During the fast charging process, the negative electrode sheet is prone to the problem of electrolyte drying up caused by lithium precipitation and side reactions. Cause battery failure; at the same time, fast charging brings higher temperature rise and binder aging problems, resulting in hard and bulging growth of negative electrodes

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