High-energy-density ternary NCA battery and preparation method therefor

Abstract

The invention belongs to the technical field of a lithium ion battery, and specifically relates to a high-energy-density ternary NCA battery and a preparation method therefor. The high-energy-density ternary NCA battery comprises a positive electrode material, a negative electrode material and an electrolyte; and the preparation method for the high-energy-density ternary NCA battery comprises the following steps of 1) preparation of a positive plate; 2) preparation of a negative plate; 3) preparation of the electrolyte; and 4) preparation of a finished battery. By virtue of improvement on the negative electrode material, the coating uniformity and density are improved without causing partial crack in circulation, generation of a new surface is suppressed, side reaction is reduced, generation of a new SEI film is reduced, and effective utilization ratio of silicon is improved; by matching with the ternary NCA positive electrode material, the material structure can be stabilized, and the normal-temperature cycling performance, the high-temperature cycling performance and the thermal stability can be improved; and meanwhile, the electrolyte is added with a positive electrode surface protecting agent, a lithium hexafluorophosphate stabilizing agent and a negative electrode SEI film forming additive, thereby improving the safety and prolonging the high-temperature cycle life of the battery.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a high energy density ternary NCA battery and a preparation method thereof. Background technique [0002] With the progress of the times and the development of science and technology, the requirements for lithium-ion batteries are getting higher and higher. Lithium-ion batteries not only need to have high energy density and power density, but also have the characteristics of long service life and high safety performance. Especially in the field of electric vehicles and large-scale energy storage, the safety requirements for lithium-ion batteries are becoming more and more urgent. [0003] Lithium-ion power batteries are the core components of electric vehicles. At present, the lithium iron phosphate system has better safety performance in the market. The energy density of its mainstream product is about 130-140Wh / kg. It is mainly used in pure electric bu...

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Problems solved by technology

[0003] Lithium-ion power batteries are the core components of electric vehicles. At present, the lithium iron phosphate system has better safety performance in the market. The energy density of its mainstream product is about 130-140Wh / kg. It is mainly used in pure electric buses. With the development of pure electric / plug-in hybrid passenger vehicles, its energy density is obviously insufficient, especially the volumetric energy density, which is not suitable for application in relatively small passenger vehicles. The ternary system (NCM ) has a weight energy density of about 160-170Wh / kg within the safety limit, and has gradually become the mainstream battery for pure electric passenger vehicles. Although it has improved to a certain extent compared with lithium iron phosphate, it still cannot meet the market requirements of light weight and long battery life Therefore, the research and application of high specific energy lithium-ion battery technology is imminent. The combination of NCA positive electrode material and Si-based negative electrode is expected to increase the energy density of single battery to 300Wh / kg, and the cycle life is ≥1500 times

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