Formation method for reducing gas retention in formation process of flexibly-packaged lithium battery

Abstract

The invention discloses a formation method for reducing gas retention in a formation process of a flexibly-packaged lithium battery. The formation method is characterized by comprising the following steps of 1) performing formation charging on an aluminum plastic film flexibly-packaged lithium cell with an aluminum plastic film airbag until the charging capacity SOC of the aluminum plastic film flexibly-packaged lithium cell reaches 10-20%; 2) forming an exhausting opening in the right upper corner of the aluminum plastic film airbag; 3) performing exhausting from the exhausting opening, and then sealing the exhausting opening; and 4) continuing to perform formation charging on the aluminum plastic film flexibly-packaged lithium cell until the formation is completed. By adoption of the formation method for reducing gas retention in the formation process of the flexibly-packaged lithium battery, a phenomenon of influence to tight fitting among a positive plate, the negative plate and a diaphragm caused by retention of a large amount of gas, which is generated by an SEI produced on the surface of a negative plate, and other side reactions in the initial period of formation, in the interior of the cell, can be avoided; and therefore, the tight fitting among the positive plate, the negative plate and the diaphragm in the formation process is ensured.

Description

technical field [0001] The invention relates to the technology in the field of batteries, in particular to a formation method for improving the formation and gas production of soft-pack lithium batteries. Background technique [0002] At present, the industry uses aluminum-plastic film as the shell of the soft-packed lithium battery. It is formed in one continuous process, that is, after charging in the cabinet until the end of the process, and then unloading the cabinet without interruption, resulting in a charge capacity of 10%-20 at the initial stage of formation. % range, a large amount of gas produced by SEI and other side reactions on the surface of the negative electrode sheet will all stay inside the cell, so that there will be an air-isolated gas area between the positive and negative electrode sheets and the separator, which is not conducive to the positive and negative electrode sheets and the separator. The tight fit is not conducive to the formation of a thin an...

AI Technical Summary

Problems solved by technology

[0002] At present, the industry uses aluminum-plastic film as the shell of the soft-packed lithium battery. It uses a continuous formation during formation, that is, after charging in the cabinet until the end of the process, and then unloading the cabinet without interruption, resulting in a charging capacity of 10%-20 at the initial stage of formation. % interval, a large amount of gas produced by SEI and other side reactions on the surface of the negative electrode sheet will all stay inside the cell, so that there will be an air-isolated gas area between the positive and negative electrode sheets and the separator, which is not conducive to the positive and negative electrode sheets and the separator. The tight fit is not conducive to the formation of a thin and dense SEI protective film on the surface of the negative electrode sheet, and it is easy to cause lithium precipitation

Images