Lithium-ion battery electrolyte and its additives

Abstract

The invention discloses a lithium ion battery electrolyte solution and its additive. The additive mainly includes N-methyl-2-pyrrolidone derivative quaternary ammonium salt and an SEI film forming additive. Compared with the prior art, in the invention, the adding of the N-methyl-2-pyrrolidone derivative quaternary ammonium salt ionic liquid additive into the lithium ion battery electrolyte solution significantly improves the wettability of the electrolyte solution on an active substance pole piece, improves the problems of low discharge capacity, poor cycle life and the like of low temperature lithium ion battery electrolyte solutions, and effectively improves the low temperature electrochemical performance of lithium ion batteries.

Description

technical field [0001] The invention belongs to the field of lithium-ion batteries, and in particular relates to an electrolytic solution capable of improving the low-temperature cycle performance of lithium-ion batteries and an additive thereof. Background technique [0002] With the rapid development of the application of lithium-ion batteries in the field of portable electrical appliances, lithium-ion battery technology is developing towards special fields such as military and aviation. At present, the main application problem of lithium-ion batteries is that the low-temperature performance cannot meet the requirements. The decline in output performance is mainly manifested in the decline in effective capacity and the drop in discharge voltage platform. [0003] The electrolyte is an ion conductor that plays a conductive role in the battery, and its performance and the interface conditions formed with the positive and negative electrodes greatly affect the temperature per...

AI Technical Summary

Problems solved by technology

Under low temperature conditions, the viscosity of the electrolyte increases and the conductivity decreases for lithium-ion batteries, resulting in very low charge and discharge capacity or even cracking, which in turn causes the product to malfunction or even explode.

After research, the solvent and additives of the electrolyte have an important impact on the performance of the battery at low temperatures. If the content of low-melting point and low-viscosity solvents is increased, the low-temperature performance of the battery is indeed improved, but its high-temperature performance will be deteriorated. Both unable to balance

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