High-temperature electrolyte solution of lithium ion battery

Abstract

The invention discloses a high-temperature electrolyte solution of a lithium ion battery. The high-temperature electrolyte solution comprises an organic solvent, a lithium salt mixture and an additive; the solvent is the hybrid reagent of cyclic carbonate containing volume fraction of 0-40% and chainlike carbonate containing volume fraction of 60-100%, the lithium salt mixture is the mixture of lithium hexafluorophosphate containing lithium molar concentration of 1.0mol/L-1.4mol/L and the novel lithium salt, and the additive is the film-forming additive with mass concentration of 0-3%, or the film-forming additive with mass concentration of 0-3% added with the dehydration acid-removal additive with mass concentration of 0-2.0%. The high-temperature cyclic performance of the lithium ion battery prepared from the high-temperature electrolyte solution provided by the invention is effectively improved.

Description

technical field [0001] The invention relates to the technical field of lithium-ion batteries, in particular to a high-temperature electrolyte for lithium-ion batteries. Background technique [0002] In recent years, high-nickel materials have been applied to electric vehicle batteries, but the increase in Ni content has made the thermal stability of the already unsafe ternary materials more uncontrollable. Combining NCM and LMFP can effectively improve the safety of batteries, but LMFP itself has the problems of electronic conductivity, low ion diffusion and the influence of Jahn-Taller, and the cycle performance of the material itself is poor, especially at high temperatures. attenuation. The high-nickel ternary itself is also prone to cation mixing due to the increase in the content of the Ni element. At the same time, the high-nickel ternary is more likely to react with water and CO2 at high temperatures, causing battery gas to affect the cycle. In the actual use of pow...

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Problems solved by technology

[0002] In recent years, high-nickel materials have been applied to electric vehicle batteries, but the increase in Ni content has made the thermal stability of the already unsafe ternary materials more uncontrollable

Combining NCM and LMFP can effectively improve the safety of batteries, but LMFP itself has the problems of electronic conductivity, low ion diffusion and the influence of Jahn-Taller, and the cycle performance of the material itself is poor, especially at high temperatures. attenuation

The high-nickel ternary itself is also prone to cation mixing due to the increase in the content of the Ni element. At the same time, the high-nickel ternary is more likely to react with water and CO2 at high temperatures, causing battery gas to affect the cycle.

In the actual use of power battery packs, even with the control of BMS, the temperature rise of the module often exceeds 50°C. At present, the cycle life of composite materials at 55°C does not exceed 500 weeks. Therefore, how to improve the cycle life of batteries under high temperature conditions become a very important issue

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