A kind of high energy density ternary NCA battery and preparation method thereof

Abstract

The invention belongs to the technical field of lithium ion batteries, and specifically relates to a high-energy-density ternary NCA battery and a preparation method thereof; the high-energy-density ternary NCA battery includes a positive electrode material, a negative electrode material and an electrolyte, and the high-energy The preparation method of the density ternary NCA battery includes the following steps: 1) preparation of the positive electrode sheet; 2) preparation of the negative electrode sheet; 3) preparation of the electrolyte; 4) production of the finished battery; the improvement of the negative electrode material will increase the coating uniformity High quality and high density, will not cause local cracks in the cycle, inhibit the appearance of new surfaces, reduce side reactions, reduce the formation of new SEI films, improve the effective use of silicon, and achieve a stable material structure with ternary NCA cathode materials , improve its normal temperature, high temperature cycle performance and thermal stability; at the same time, add positive electrode surface protection agent, lithium hexafluorophosphate stabilizer and negative electrode SEI film forming additive to the electrolyte to improve battery safety and high temperature cycle life.

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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