Method for detecting corrosion condition inside lithium ion battery with flexible package

Abstract

The invention relates to the field of a lithium ion battery, and discloses a method for detecting a corrosion condition inside a lithium ion battery with a flexible package. The method comprises the following steps: respectively measuring voltage between an anode and a cathode of the lithium ion battery and voltage between an anode lug and an aluminum layer of an aluminum-plastic composite film by using a voltage meter; comparing the voltage between the anode and the cathode of the lithium ion battery and the voltage between the anode lug and the aluminum layer of the aluminum-plastic composite film; and if the voltage between the anode lug and the aluminum layer is equal to or slightly less than a battery principle voltage value, corroding the aluminum layer of the aluminum-plastic composite film; or measuring the resistance between the anode lug and the aluminum layer of the aluminum-plastic composite film by using a universal meter in a more simple and convenient manner, and if a measured resistance value is less than 100ohms, corroding the aluminum layer of the aluminum-plastic composite film. According to the method, the measurement is rapid and accurate, the production efficiency and the product quality are greatly improved, the screening of the uniformity of lithium-ion monomer battery is facilitated, and the production cost can be effectively lowered without complex equipment and process.

Description

technical field [0001] The invention relates to the field of lithium batteries, in particular to a detection method for internal corrosion of soft-packaged lithium-ion batteries. Background technique [0002] Flexible packaging lithium-ion batteries usually use aluminum-plastic composite film as the outer packaging material for cell packaging. The basic composition of the aluminum-plastic composite film is the inner CPP heat-sealing adhesive layer, the middle aluminum layer and the outer nylon protective layer. When the flexible packaging lithium-ion battery is packaged in the cell, burrs or active material particles may remain around the cell. During the pumping process, these burrs or particles will pierce the inner heat-sealing film to the aluminum layer; or during the cell packaging process In this process, due to mechanical action or over-melting during heat sealing, the inner heat-sealing film of the aluminum-plastic composite film is damaged, and the aluminum layer i...

AI Technical Summary

Problems solved by technology

When the flexible packaging lithium-ion battery is packaged in the cell, burrs or active material particles may remain around the cell. During the pumping process, these burrs or particles will pierce the inner heat-sealing film to the aluminum layer; or during the cell packaging process In this process, due to mechanical action or over-melting during heat sealing, the inner heat-sealing film of the aluminum-plastic composite film is damaged, and the aluminum layer is directly in contact with the electrolyte. At this time, the trace amount of hydrofluoric acid in the electrolyte will contact the aluminum layer and cause a point If corrosion occurs at the heat seal position of the negative tab, it will accelerate electrochemical corrosion, change the composition of the electrolyte, and in severe cases, corrode the aluminum layer and cause battery leakage, which will bring serious safety hazards and cause the battery to be scrapped

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