Lithium ion battery electrolyte for improving battery pole piece interface

Abstract

The invention relates to the technical field of a lithium ion battery, in particular to a lithium ion battery electrolyte for improving a battery pole piece interface. The lithium ion battery electrolyte comprises a non-aqueous organic solvent, a lithium salt and an additive, wherein the non-aqueous organic solvent comprises at least one of carboxylic ester, halogenated carbonic ester, aromatic hydrocarbon and halogenated aromatics thereof, and the additive comprises at least one of a lithium salt additive, fluoro carbonic ester, fluoro-ether, phosphonitrile and derivatives thereof. Compared with the prior art, the lithium ion battery electrolyte has the advantages that the solvent and the additive are used in a combination way to generate a synergic effect, the electrolyte has a favorable negative electrode interface in a low-temperature and rapid charging / discharging environments, no lithium is precipitated, thus, the requirements of low-temperature charging and discharging, rapid charging and discharging and high compaction density of a negative electrode pole plate can be simultaneously met, and meanwhile, the potential risk caused by lithium precipitation during the charging of the battery is reduced.

Description

technical field [0001] The invention relates to the technical field of lithium ion batteries, in particular to a lithium ion battery electrolyte for improving the interface of lithium battery pole pieces. Background technique [0002] Lithium-ion batteries are widely used in 3C digital products, electric vehicles, military aerospace and other fields due to their high working voltage, high energy density, long cycle life, and environmental friendliness. With the improvement of people's living standards, higher requirements are put forward for the working environment, energy density, and fast charging and discharging of lithium-ion batteries. [0003] The discharge capacity of lithium-ion batteries decays quickly in low-temperature environments, and the negative electrode interface is prone to lithium deposition in low-temperature environments, resulting in irreversible damage to the battery. In severe cases, it is more likely to cause safety hazards due to lithium deposition ...

AI Technical Summary

Problems solved by technology

[0003] The discharge capacity of lithium-ion batteries decays quickly in low-temperature environments, and the interface of the negative electrode in low-temperature environments is prone to lithium deposition, resulting in irreversible damage to the battery. In severe cases, it is more likely to cause safety hazards due to lithium deposition in the battery

One way to increase the energy density of the battery is to increase the compaction density of the battery pole piece, but the increase in the compaction density means that the mass transfer and conductivity speed of the material is reduced, and the impedance is increased, which makes the pole piece prone to exist during the use of the battery. Lithium, dark spots, etc.

On the other hand, during the rapid charging of lithium batteries, more lithium ions are released from the positive electrode into the negative electrode per unit time, and the lithium ions cannot be completely embedded in the negative electrode due to the mass transfer resistance of the negative electrode under the drive of a large current. Staying on the outside of the pole piece will cause lithium precipitation and block the lithium ion transmission channel. Over time, the battery will become thicker and deformed, which will easily cause safety risks

Images