Electrolyte containing phosphite lithium salt flame-retardant additive and lithium ion battery

Abstract

The invention relates to an electrolyte containing a phosphite lithium salt flame-retardant additive. The electrolyte comprises 2%-20% of a lithium salt, 0.1%-10% of the phosphite lithium salt flame-retardant additive, 0.1%-10% of a film-forming additive and 70%-90% of a non-aqueous organic solvent. The lithium ion battery comprises a positive electrode, a negative electrode, a diaphragm and the electrolyte. The electrolyte disclosed by the invention has the characteristic of noninflammability and is relatively low in viscosity; the lithium ion battery using the electrolyte provided by the invention has relatively high specific discharge capacity, and thermal runaway does not occur in a thermal shock test.

Description

technical field [0001] The invention relates to the technical field of lithium ion batteries, in particular to an electrolyte containing a phosphite lithium salt flame retardant additive and a lithium ion battery. Background technique [0002] Lithium-ion batteries have significant advantages such as high power, high energy density, low self-discharge rate, good cycle performance, green and pollution-free, and are widely used in 3C electronic products, wearable medical equipment, power tools, electric vehicles and ships, aerospace, energy storage and other fields. In recent years, the country has vigorously promoted green energy, which has promoted the rapid development of lithium-ion batteries in the field of electric vehicles, but the safety issues of lithium-ion batteries have become increasingly prominent. With the improvement of people's safety requirements for electric vehicles, the safety of lithium-ion batteries has also been greatly challenged. [0003] The therma...

AI Technical Summary

Problems solved by technology

On the one hand, it is to carry out scientific battery management, such as installing PTC (positive temperature coefficient) components in the battery. When the battery temperature rises, the internal resistance of the battery will increase rapidly, thereby reducing the current to achieve battery protection; When the internal pressure of the battery reaches a critical value, the explosion-proof valve bursts instantly and discharges a large amount of gas, quickly releasing the internal pressure of the battery, preventing the battery from exploding or reducing the damage caused by the explosion; although external management can play a certain protective effect, it will Increase the difficulty of battery manufacturing, increase the manufacturing cost of batteries, and cannot fundamentally solve the safety problem of batteries

On the other hand, start from the battery itself to improve the stability of the battery material, such as modifying the positive and negative electrode materials of the battery to reduce the side reactions caused by the electrode material and the electrolyte, and reduce heat generation; it can also be prepared using a special process The diaphragm reduces the internal short circuit caused by negative electrode dendrite puncture, and reduces the risk of battery thermal runaway; it can also improve the electrolyte system, use lightning, organic solvents with higher boiling points, and use organophosphorus, silicon, and nitrogen-containing compounds. Combustion additives, etc.; however, the modification of positive and negative electrode materials and the use of special separators will greatly increase the cost of the battery. Although the use of the above-mentioned electrolyte additives can fundamentally prevent thermal runaway, it will increase the cost of the battery and increase the viscosity of the electrolyte. Reduce the conductivity of the electrolyte and degrade battery performance

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