Air-exhausting secondary packaging method for soft package battery cell

Abstract

The invention belongs to the technical field of lithium ion batteries, and particularly relates to an air-exhausting secondary packaging method for a soft package battery cell. The method comprises the following steps of puncturing an air bag of a formed soft package battery cell, sectionally vacuumizing a sealed cavity in which the soft package battery cell is positioned to a set vacuum degree, and performing secondary packaging on the soft package battery cell. Compared with a traditional thorough-pumping air exhausting method, a sectional vacuumizing method is adopted in an air-exhausting secondary packaging step so as to allow a vacuum degree to slowly reach a set value in sections; that is, a vacuumizing speed is reduced, and vacuumizing time is prolonged; and thus, on one hand, the situation that a liquid loss amount cannot be controlled and the liquid retention degree of the battery cell is reduced due to rushing-out of an electrolyte and that the cycle performance of the battery cell is influenced can be avoided, and on the other hand, the battery cell can be prevented from being polluted by the electrolyte that rushes out, and the defective rate of battery cells in the air-exhausting secondary packaging process is reduced.

Description

technical field [0001] The invention belongs to the technical field of lithium-ion batteries, and in particular relates to a method for pumping and sealing two batteries in a soft package. Background technique [0002] Since the commercialization of lithium-ion batteries in the 1990s, due to their high energy density, high operating voltage, and light weight, they have been widely used in mobile phones, notebook computers, tablet computers, Bluetooth headsets, MP3, and digital cameras. . Lithium-ion batteries are mainly divided into cylindrical batteries, square batteries and soft pack batteries according to their shapes, while cylindrical batteries and square batteries are also called hard shell batteries. Compared with hard-shell batteries, soft-pack batteries have the advantages of flexible design, lighter weight, low internal resistance, less explosion, more cycle times, and high energy density. Therefore, soft-pack batteries will occupy a higher proportion of the marke...

AI Technical Summary

Problems solved by technology

[0005] However, there is no corresponding control on the vacuum degree of the second-sealing pumping method in the existing method. Often when the vacuum is pumped to the bottom, the vacuum degree soars rapidly, which will cause the free electrolyte to surge out, resulting in an uncontrollable amount of electrolyte pumped out. The electrolyte will contaminate the main body of the battery cell, which is more serious for larger pouch batteries

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