Formation method of lithium ion battery

Abstract

A formation method of a lithium ion battery comprises the following steps of placing an aged battery in a formation device for formation in a high-temperature pressurized environment, charging by using 0.1-0.5CmA current during charging until to a cut-off voltage of 3.7V, and then charging by using 0.5-2.0CmA current until to a cut-off voltage of 4.0V; increasing the temperature and keeping the pressure unchanged, and carrying out heat preservation and pressure maintaining on the battery; reducing the temperature and the pressure, and cooling the battery; and carrying out vacuum pumping and secondary sealing on the battery subjected to cooling finish, and completing formation. According to the formation method, a battery core is placed in a high temperature and certain pressure condition for large-current charging formation, the processing time is shortened, and the production efficiency is improved; moreover, the contact of an operator to the lithium battery core is reduced, and the cost problems caused by poor appearance, damage and the like are reduced; and the consistencies on the thickness, the capacity and pole piece interface states of the battery are higher, and the cycle ability 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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