Lithium ion battery, cathode thereof and binder for cathode

Abstract

The invention belongs to the field of lithium ion battery material and particularly relates to a lithium ion battery, a cathode thereof and a binder for the cathode. The binder is formed by polymerizing the monomer emulsion of butadiene, Rn-CH=C-CN and CH3-C=CH-COORm; and the product is purified to obtain emulsion containing 35-55% of glue. The invention also provides a method for manufacturing a cathode plate by using the binder and battery performance thereof. The slurry of cathode active substance comprises active substance, conductive carbon, binder, sodium carboxymethylcellulose and deionized water based on the proportion of (85-98):(0-3):(1-10):(1-2):(100-150). The method comprises the following steps: coating the slurry on copper foil; drying; compacting with a rolling machine; chopping to obtain an electrode plate; and winding the electrode plate with an anode plate to obtain the battery. The manufactured battery has good low-temperature performance, ensures that lithium is not separated out under the condition of 0.7C charge and 0.5C discharge at the temperature of 10 DEG C, and has the characteristics of safety, reliability and long cycle life.

Description

technical field [0001] The invention belongs to the field of lithium-ion battery materials, and more specifically relates to a lithium-ion battery with good low-temperature performance, a negative electrode thereof, and a binder used in the negative electrode. Background technique [0002] Since its commercialization, lithium-ion batteries have been widely used as power sources for various mobile devices due to their high energy density, high working voltage, no memory effect, long cycle life, and no pollution to the environment. The practical phase of the scale. [0003] The characteristics of lithium-ion batteries can be developed by improving the components of the battery. The performance of the battery depends on the electrodes, electrolyte and battery materials contained therein, while the characteristics of the electrodes depend on the active materials, current collectors and binders of the battery. The agent provides the adhesion between the battery active material a...

AI Technical Summary

Problems solved by technology

[0004] In recent years, gratifying achievements have been made in the research and development of lithium-ion batteries, especially in the improvement of energy density. However, the research on the improvement of low-temperature performance of lithium-ion batteries is relatively lagging behind, which has become a constraint on the lithium-ion battery market and Bottlenecks in the application field

At present, water-based negative electrode sheets of lithium-ion batteries generally use styrene-butadiene rubber (SBR) as a binder, which has excellent elastic properties, but such binder polymers are not compatible with the solvents used in battery electrolytes. The difference in affinity between them leads to the inability of the polar electrolyte to penetrate into the active material particles of the electrode, which increases the interface resistance of the electrode and the internal resistance of the battery. This phenomenon is more obvious at low temperatures, manifested as At room temperature and the battery is easy to decompose lithium, and as the coating weight increases, the lithium decomposition of the battery becomes more serious, which seriously affects the safety performance of the battery

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