A kind of formation method of lithium ion battery

Abstract

A lithium-ion battery formation method, the steps are as follows: Put the battery that has aged to a certain point into the formation equipment and perform formation under high temperature and pressure environment. When charging, first use 0.1-0.5CmA current to charge, and charge to the cut-off voltage of 3.7 V, and then use 0.5C ~ 2.0CmA current to charge, charge to the cut-off voltage of 4.0V; raise the temperature, keep the pressure constant, keep the battery warm and pressurized; lower the temperature and pressure, cool the battery; The cooled battery is vacuumized and sealed for the second time, and the formation is completed. In the invention, the batteries are placed under high temperature and certain pressure conditions for high-current charging and formation, which shortens the process time, improves production efficiency, and reduces the contact of operators with lithium-ion batteries, reducing poor appearance and damage, etc. The cost problem brought about; the thickness, capacity, and interface state of the pole piece of the battery are more consistent, and the cycle capacity is improved.

Description

technical field [0001] The invention belongs to the technical field of polymer lithium-ion battery manufacturing, and in particular relates to a chemical formation method capable of improving the interface state of positive and negative electrodes of lithium-ion batteries and solving the problem of gelation of liquid electrolyte. Background technique [0002] The battery needs to go through a formation process before use, so as to activate the active materials of the positive and negative electrodes of the battery, so that the battery can reach the best charge and discharge state. The formation of the battery generally refers to the first charge of the battery. The formation process is related to the quality of the battery capacity, cycle life and safety performance. Therefore, the formation process determines the performance of the battery to a certain extent. [0003] The existing chemical formation process is generally to continuously charge the battery at room temperatur...

AI Technical Summary

Problems solved by technology

Although this process improves the production efficiency and reduces the number of human contacts to the battery during the process, however, because the separator used in the high-voltage battery is coated with polyvinylidene fluoride (PVDF) and ceramics, the battery produced by this method The interface state of the core positive and negative electrodes is not consistent, and there are cases where the coating of the positive and negative electrodes is peeled off by the adhesive material of the separator and the ceramics fall off and stick to the electrode, and this method is prone to insufficient hardness of the battery and PVDF on the separator during the manufacturing process. The appearance of the cell is uneven due to the gelation of the electrolyte and the formation of bumps

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