Why should the lithium battery pack undergo aging test before leaving the factory? The lithium battery pack has an aging system. This aging behavior generally refers to the placement of the lithium battery after the completion of the liquid injection, after the first charge and discharge, and there is a high temperature aging at room temperature. Lithium battery manufacturers This article will introduce why the lithium battery pack should be aging tested before leaving the factory.
Why should the lithium battery pack undergo aging test before leaving the factory?
The aging of the lithium battery pack generally refers to the placement after the secondary charging of the battery assembly, and may have both normal temperature aging and high temperature aging, and the effect is to stabilize the properties and composition of the SEI film formed after the initial charging.
The lithium battery pack has a normal temperature aging temperature of 25 degrees, and the high temperature aging varies from factory to factory, and some are 38 degrees and 45 degrees, and the time is between 48 and 72 hours.
Lithium battery packs are mainly used for aging before leaving the factory.
First, the electrolyte is more infiltrated, which is beneficial to the stability of the performance of the lithium battery;
Second, after the aging of the active material in the positive and negative materials, it can promote the acceleration of some side effects, such as gas production, electrolyte decomposition, etc., so that the electrochemical performance of the lithium battery pack can be quickly stabilized;
The third is to conduct a lithium battery consistency check after aging for a period of time. After the formation, the voltage of the cell is unstable, and the measured value will deviate from the actual value. The voltage and internal resistance of the cell after aging are more stable, and it is convenient to screen the battery with high consistency.
There are two main factors affecting the performance of the lithium battery pack in the aging system, namely aging temperature and aging time. In addition, it is also important that the battery is in a sealed or open state during aging.
The performance of lithium battery after high temperature aging is more stable. Most lithium ion battery manufacturers adopt high temperature aging operation mode during the production process. The temperature is 45~50 degrees Celsius and aging for 1~3 days, and then it is kept at room temperature. Potential defects in the battery will be exposed after high temperature aging: such as voltage changes, thickness changes, internal resistance changes are a comprehensive test of the safety and electrochemical performance of this batch of batteries.
Effect of aging of lithium battery pack on battery performance
1, stability energy
At normal temperature or at high temperatures, the lithium battery pack is left for a period of time for aging. This is beneficial to the electrolyte to fully infiltrate the pole piece, which is convenient for stabilizing the performance of the lithium battery pack.
2. SEI restructuring
After the pre-forming process of the lithium battery, the graphite anode inside the battery will form a certain amount of SEI film, but the film structure is compact and the pores are small, and the battery is aged at a high temperature, which contributes to the reorganization of the SEI structure and forms a loose porous film. .
3. Speed up side reactions
The aging treatment helps the lithium battery to be unstable after the formation of the battery as soon as possible. After the aging of the active material in the positive and negative materials, it can accelerate the progress of some side reactions, and the electrochemical performance of the lithium battery pack can be stabilized more quickly.
Lithium battery pack aging is very normal, but it is often used in a limited amount. If it is not filled in time, it will be used quickly and the aging speed will be very fast. Battery life can be extended by changing battery electrodes or changing the charging method to increase uniform charging and discharging.