Formation method of soft package lithium ion battery

Abstract

The invention provides a formation method of a soft package lithium ion battery, and belongs to the technical field of lithium ion battery manufacturing. By the formation method, the problems that howgas in the soft package lithium ion battery is effectively discharged and the formation of a more compact and stable SEI film is facilitated are solved. The formation method of the soft package lithium ion battery comprises the steps of performing pre-charging formation, secondary vacuumizing and small-current charging formation on the lithium ion battery, before pre-charging formation, performing primary vacuumizing on the lithium ion battery subjected to liquid injection and being immersed at a normal temperature to preset vacuum, performing vacuum thermal package, performing primary front-surface and back-surface rolling on the lithium ion battery after vacuum hot sealing by a rolling device, performing high-temperature immersion, reducing a temperature to a room temperature, and performing secondary front-surface and back-surface rolling on the lithium ion battery after vacuum hot sealing by a rolling device between secondary vacuumizing and small-current formation. By the method,the more compact and stable SEI film is formed on a surface of a lithium ion battery negative electrode in a high-energy consumption mode in a more stable and safer environment, so that the performance of all aspects of the lithium ion battery is improved.

Description

technical field [0001] The invention belongs to the technical field of lithium-ion battery manufacturing, and relates to a method for forming a soft-pack lithium-ion battery. Background technique [0002] In the production process of lithium-ion batteries, formation is an extremely important process, which is to fully activate the active materials of the battery. The quality of formation directly affects the subsequent performance of lithium-ion batteries. During formation, a passivation film is formed on the surface of the negative electrode, that is, the solid electrolyte interface film is referred to as the SEI film. The quality of the SEI film directly affects the electrochemical performance of the battery such as cycle life, stability, self-discharge, and safety. The SEI films formed by different chemical formation processes are different, and the impact on battery performance is also very different. Especially for capacity development and cycle life, the capacity perf...

AI Technical Summary

Problems solved by technology

This method solves the problem of how to effectively remove the gas in the battery manufacturing process and promote the formation of a denser and more stable SEI film on the surface of the negative electrode of the battery.

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