Rapid forming method of lithium ion power battery

Abstract

The invention discloses a rapid forming method of a lithium ion power battery, which is characterized by comprising the following steps of: 1. precharging; 2. settling and aging; and 3. charging by adopting an intermittent depolarized single-stage impulse charging mode until charge is finished. Because the forming process of the invention adopts the intermittent depolarized single-stage impulse charging mode, the impedance of an SEI (Solid Electrolyte Interface) membrane is lowered, thereby reducing the internal resistance of the battery and improving the rate discharge performance of the lithium ion power battery. Because the forming process of the invention adopts an impulse current with a lower frequency, the battery can be naturally depolarized within the impulse-off time, thereby lowering the polarizing effect, stabilizing the charging voltage, improving the charging efficiency, simultaneously avoiding the high requirement brought by a high frequency impulse current charging mode for equipment, improving the utilization efficiency of electric energy and greatly lowering the production cost. The step of precharge is adopted to facilitate the formation of the stable SEI membrane, thereby improving the performance of the battery.

Description

technical field [0001] The invention relates to a lithium ion power battery formation process, in particular to a lithium ion power battery rapid formation method. Background technique [0002] In the production process of lithium-ion power batteries, formation is the process that requires the most equipment and occupies the largest area of ​​the plant, and is an extremely critical link in battery production. In this process, a layer of solid electrolyte interfacial SEI film is formed on the surface of the negative electrode, thereby improving the stability of the electrode performance. The performance of the finished lithium-ion battery depends to a large extent on whether the formation effect is good or not. [0003] Generally speaking, the commonly used process in actual production is to use a small current for a long time to charge to complete the formation process. During the formation process, the SEI film formed on the surface of the negative electrode will be diffe...

AI Technical Summary

Problems solved by technology

Low current formation helps to form a stable SEI film, thereby effectively improving the performance of the battery, but this method has the following disadvantages: 1. Long-term low-current charging will lead to an increase in the impedance of the SEI film, thereby increasing the internal resistance of the battery , affecting the rate discharge performance of the battery

2. The formation time of small current is longer, which affects the production efficiency. However, although charging with high current can speed up the formation time, it is easy to damage the formation of SEI film and lead to the deterioration of battery performance.

3. In the process of charging with high current or low current, polarization phenomena composed of ohmic polarization, concentration polarization and electrochemical polarization will inevitably occur, resulting in an increase in charging voltage and a decrease in charging efficiency

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