A liquid injection process for polymer soft pack lithium ion battery

Abstract

The invention relates to the field of lithium-ion batteries, in particular to a liquid injection process for polymer soft-pack lithium-ion batteries, comprising the following steps: (1) sealing the top and side of the soft-pack batteries, and putting them into a drying box to dry 1 to 2 hours; (2) Seal the side of the air bag of the soft battery cell taken out of the drying box, and then use a puncture needle to penetrate the air bag and inject electrolyte into the cell. The amount of liquid injected is the total amount of electrolyte 105-120% of the liquid injection hole, seal the liquid injection hole with tape or clips, and let it stand for 30-40 minutes; (3) perform formation on the soft-packed battery; (4) remove the tape or clip from the liquid injection hole after the formation is completed , vacuum through the liquid injection hole, and then perform two seals on the soft-packed battery; (5) remove the air bag to complete the liquid injection; the liquid injection process adopted in the present invention can be completed completely in the workshop environment, without the need for a glove box It significantly improves the liquid injection efficiency of the soft-packed battery cell and increases the production capacity; at the same time, it ensures the liquid injection volume of the battery and avoids the pollution of the ambient air caused by the volatilization and leakage of the electrolyte.

Description

technical field [0001] The invention relates to the field of lithium-ion batteries, in particular to a liquid injection process for polymer soft-pack lithium-ion batteries. Background technique [0002] Lithium-ion battery electrolyte is an organic liquid, including the inorganic salt LiPF 6 And some additives, such as: PC (propylene carbonate), EC (ethylene carbonate), DMC (dimethyl carbonate), DEC (diethyl carbonate), EMC (methyl ethyl carbonate), etc., these substances are mixed as The electrolyte of lithium-ion batteries is used to transport lithium ions to realize intercalation and deintercalation of electrons, due to LiPF 6 When encountering water, a chemical reaction will occur and HF (hydrofluoric acid) will be generated. HF (hydrofluoric acid) will destroy the SEI film, causing secondary film formation, resulting in deterioration of the performance of the lithium battery, such as lithium analysis, lithium battery charging and discharging. When water is electrolyze...

AI Technical Summary

Problems solved by technology

The traditional glove box injection method has many disadvantages: 1. Even if a dehumidification system is used for dehumidification, the moisture in the glove box is still above 500ppm, while high-quality lithium batteries require moisture to be controlled at about 10ppm, which is very different, so it is difficult to Preserve high-quality lithium batteries; 2. The dehumidification operation of the glove box consumes a lot of energy and has high environmental requirements for the entire workshop, resulting in high cost of lithium battery injection operations; 3. When performing liquid injection operations in the glove box , the electrolyte is easy to volatilize and is discharged into the air by the return air system to pollute the environment; 4. When injecting liquid in the glove box, the operator has to insert his hands in latex long-arm gloves for a long time, which is easy to cause if the time is too long It causes skin sweating and eczema, etc., and it is extremely inconvenient to wear latex long-arm gloves for liquid injection, which seriously affects the production capacity of the lithium battery liquid injection process