Ternary lithium battery electrolyte and high-temperature resistant, high-capacity and high-safety lithium battery core

Abstract

The invention discloses a ternary lithium battery electrolyte and a high-temperature resistant, high-capacity and high-safety lithium battery core. According to the lithium battery core, a high-temperature resistant high-safety electrolyte is prepared by adopting a novel lithium salt of a conductive lithium salt LiBOB (lithium bis(oxalate)borate) and a lithium salt LiFSI (lithium bis(fluorosulfonyl)imide) and adding a proper amount of additive of FEC (fluoroethylene carbonate), MMDS (methylene methanedisulfonate) and TMP (trimethyl phosphate). A novel ternary positive electrode material coatedwith a mixture of nano titanium dioxide and a ternary material (LiNi0.8Co0.1Mn0.1O2) is adopted by a positive electrode, and a mixture of mesocarbon microbeads MCMB and carbon nanotubes is adopted bya negative electrode, thereby preparing the novel high-temperature resistant high-capacity lithium-ion power battery core for an automobile. According to the prepared battery core, the cycle performance is improved, and meanwhile, the problem of high-temperature air expansion is well solved.

Description

technical field [0001] The invention relates to the field of lithium batteries, in particular to an electrolyte solution for a ternary lithium battery and a lithium battery cell with high temperature resistance, high capacity and high safety. Background technique [0002] With the diversification of the use of power batteries, consumers have higher and higher requirements for the energy density of power batteries. The development of high-capacity and high-energy-density lithium-ion batteries is mainly achieved by developing high-capacity positive electrodes, increasing the charging voltage of positive electrodes, and high-capacity negative electrodes. [0003] Ternary materials have relatively high energy density. On the one hand, increasing the nickel content (nickel-cobalt-lithium manganate system) can greatly increase the specific capacity of the material; on the other hand, increasing the charging voltage can further increase the energy density. However, the charging vo...

AI Technical Summary

Problems solved by technology

However, the charging voltage of high-nickel ternary materials is relatively high (generally needs to be charged above 4.6V), while the electrolyte system composed of conventional carbonate solvent and lithium hexafluorophosphate will decompose when it is above 4.5V (vs. Li / Li+), As a result, the performance of the entire battery system is reduced, especially the capacity is rapidly attenuated. Therefore, it is of great significance to study high-voltage electrolytes suitable for high-nickel ternary cathode material systems for lithium-ion batteries.

[0004] In addition, when the charging voltage of the positive electrode material increases, the oxidative decomposition of the electrolyte will intensify, resulting in the deterioration of battery performance.

In addition, for high-voltage batteries, the dissolution of positive metal ions is common during use, especially after the battery has been stored at high temperature for a long time, the dissolution of positive metal ions is further intensified, resulting in low battery retention capacity.

[0005] Power vehicle batteries have high requirements on the safety and high temperature of batteries. With the increase of energy density, ternary power batteries will dominate the market, and the safety performance and high temperature performance of the existing ternary system cannot meet the requirements of the whole vehicle. demand, the present invention just solves this problem

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