Formation method for soft package lithium-ion battery with lithium iron phosphate as anode

Abstract

The invention provides a formation method for a soft package lithium-ion battery with lithium iron phosphate as an anode, which belongs to the technical field of lithium-ion battery manufacturing processes. The whole formation process is mainly divided into four stages of charging, storage, recharging and re-storage; the charging voltage in the first stage is controlled at a low voltage section; and when the battery is stored for a longer time at the low voltage section, local overcharge of the surface of a pole piece can be preferably avoided; a vacuum-pumping step is available after the charging in both the first stage and the third stage; as the gas generated by the battery formation is eliminated as much as possible, non-uniform reaction of the pole piece caused by internal gas can be also preferably avoided; and as voltage drop screening is carried out in both the second stage (low voltage section) and the fourth stage (high voltage section), a problem that capacity graded battery with poor voltage maintaining performance is hard to screen can be also solved. According to the invention, problems that local overcharge is caused by large gas production and poor pole piece surface consistency and the battery with poor voltage maintaining performance is hard to screen in the formation process of the lithium iron phosphate soft package lithium-ion battery are solved.

Description

technical field [0001] The invention belongs to the technical field of lithium-ion battery production technology, and in particular relates to a method for forming a flexible-package lithium-ion battery with lithium iron phosphate as the positive electrode. Background technique [0002] There are many reports on the formation methods of lithium-ion batteries, but for lithium iron phosphate as the positive electrode, there are few formation methods using flexible packaging as the outer shell. At present, lithium iron phosphate flexible packaging batteries are mostly large-capacity power batteries. The formation process produces a large amount of gas, it is difficult to control the local overcharge of the pole piece, and it is difficult to screen out batteries with poor pressure holding performance. Contents of the invention [0003] The object of the present invention is to provide a lithium iron phosphate flexible package in which the gas generated during the formation of ...

AI Technical Summary

Problems solved by technology

[0002] There are many reports on the formation methods of lithium-ion batteries, but for lithium iron phosphate as the positive electrode, there are few formation methods using flexible packaging as the outer shell.

At present, lithium iron phosphate flexible packaging batteries are mostly large-capacity power batteries. The formation process produces a large amount of gas, it is difficult to control the partial overcharge of the pole piece, and it is difficult to screen out batteries with poor pressure holding performance.