Forming method of lithium ion secondary battery using vacuum system

Abstract

The invention discloses a forming method of lithium ion secondary batteries by using a vacuum system, and relates to a forming method of lithium ion batteries, which is characterized in that: the vacuum system is added and applied during the forming process, which leads the lithium ion secondary batteries to be capable of exhausting generated gas during the forming process, while uniform and solid electrolyte interface films (SEI film) can be formed by each part of pole pieces so as to improve the cycle performance as well as the high-rate discharge property of the lithium ion secondary batteries. In addition, the forming method of the lithium ion batteries can also solve the problems of insufficient electrolyte and the corrosion of battery shells caused by the overflow of the electrolyte during the forming process, thus saving the materials and production cost.

Description

technical field [0001] The invention relates to a method for forming a lithium ion battery, more specifically to a method for forming a lithium ion secondary battery using a graphite negative electrode. Background technique [0002] Since the successful commercialization of lithium-ion secondary batteries in the 1990s, they have rapidly occupied the field of high-end mobile electronics with their outstanding charge-discharge performance and high energy density. In recent years, with the advancement of battery technology and the increasing availability of petroleum resources Lithium-ion secondary batteries have gradually entered the application fields that require high power and high energy density, such as electric vehicles and large UPS power supplies. Contrary to the continuous commercialization of new positive electrode materials, the negative electrode materials of lithium-ion secondary batteries are always carbon materials represented by artificial graphite, natural gra...

AI Technical Summary

Problems solved by technology

[0004] Existing studies have shown that during formation, the relevant components in the electrolyte will react on the surface of the carbon material. In addition to forming an SEI film, it will also generate various gases such as ethylene, carbon dioxide, hydrogen, and carbon monoxide. If the gas cannot be discharged from the cell in time, It will cause uneven formation of SEI film on the negative electrode, which will affect the cycle life and rate characteristics of the battery.

Based on the above understanding, in the current chemical formation process, most of the initial small current charging, adding static steps to exhaust and improve the SEI film, and centrifugal exhaust to weaken the impact of the generated gas, these methods are time-consuming , laborious and unable to achieve the best exhaust and film forming effect