Formation method for lithium ion battery

Abstract

The invention discloses a formation method for a lithium ion battery. The formation method comprises the following steps of putting a cell which is fully aged into formation equipment to be subjected to high-temperature pressurizing formation, wherein the charging cut-off voltage is 3.5-3.8V; cooling the cell at a normal temperature and fixed pressure to reduce the temperature of the cell to the room temperature; putting the cooled cell into a vacuum environment, puncturing an airbag of the cell, and performing air exhausting and then sealing the opening; putting the cell which is subjected to complete air exhausting into the formation equipment to be subjected to high-temperature pressurizing formation, wherein the charging cut-off voltage is 3.9-4.5V; increasing the temperature and the pressure, and performing thermal insulation and pressure maintaining on the battery; and cooling the cell at a normal temperature and fixed pressure to reduce the temperature of the cell to the room temperature, and finishing the formation. According to the formation method, the steps of puncturing the airbag of the cell and air exhausting are added in the thermal pressure formation, so that the reaction gas can be discharged in time, and the performance of the lithium battery is improved.

Description

Technical field [0001] The invention belongs to the technical field of lithium ion battery manufacturing, and particularly relates to a formation method of a lithium ion battery. Background technique [0002] Formation is an indispensable process in the production process of lithium batteries, and it plays a vital role in the performance of lithium batteries. Especially for soft-packed lithium batteries, the formation not only has the functions of activating the electrode material, improving the interface of the lithium battery, self-discharge, and cycling, but also has the functions of enhancing the hardness of the battery core and shaping. In order to save production time, improve labor efficiency, and reduce costs, soft-pack lithium batteries have begun to adopt high temperature, high pressure, and high current formation processes. Formation under high temperature and high pressure can not only improve the performance of lithium batteries, but also effectively increase the har...

AI Technical Summary

Problems solved by technology

Due to high temperature and high pressure, the internal electrochemical reaction of the lithium battery is enhanced, and more side reactions will generate more gas impurities. If the gas cannot be removed in time, the gas will remain inside the battery cell, which will have an adverse effect on the performance of the lithium battery. For example, adding more batteries Internal resistance, increasing the lithium ion conduction resistance inside the lithium battery, destroying the state of the battery electrode interface, reducing the cycle performance and storage time of the lithium battery, etc.

Images