What is the operation of cell separation? What does it do?

In the manufacturing process of mobile phone batteries, cell separation is an indispensable and important process. What is the operation of cell separation? What exactly does it do?

Cell capacity separation refers to the process of screening out qualified batteries through capacity testing. To put it simply, the data of each detection point is obtained through computer management, so as to analyse the data such as the size of the battery capacity and internal resistance, and determine the quality level of the battery. Generally speaking, cells are divided into four groups: normal, high-capacitance, low-capacitance, and failure.

Why do you need to do cell capacitance?

Because after the production of the single cell of the battery is completed, the parameters in terms of capacity, voltage, current, internal resistance and other aspects are not consistent due to the constraints of the battery production process, so it is necessary to form and divide the battery to maintain the consistency of the lithium battery cell.

The specific role of cell capacitance

The role of cell capacitance is mainly reflected in the following aspects:

Quality Screening: Capacity sorting can help screen out the parts of the battery that are inconsistent in quality, ensuring that each battery is a rigorously tested product.

Performance screening: Capacity separation can ensure that the performance of the battery meets the design requirements and improve the consistency and reliability of the battery pack.

SEI film stability: Volume separation is conducive to the stability of SEI film, shortens the process time, reduces energy consumption, and improves production capacity. SEI film refers to a passivation film covering the electrode surface formed by the chemical reaction between the electrolyte and the electrode material at the solid-liquid interface during the first charge and discharge process of the lithium-ion battery. This film has the characteristics of a solid electrolyte and is an electronic insulator, but it is an excellent conductor of Li+, allowing Li+ to be freely embedded and detached. SEI film can avoid the damage caused by organic solvents to the electrode material, and improve the cycle performance and service life of the battery.

Classification grouping: Cells with similar performance can be combined through capacitance to improve the overall performance of the battery pack.

Safety: Capacitance can reduce the probability of unbalanced state in the battery pack and improve safety.

Procedures and equipment for cell separation

Cell separating is usually done in a chemical capacity cabinet, which is capable of charging and discharging a large number of batteries at the same time.

Formation refers to the activation of the positive and negative electrode substances inside the battery cell through charging and discharging after the cell is manufactured, so as to improve the self-discharge, charge-discharge performance and storage performance of the battery.

Capacity classification refers to the grading of battery capacity by testing battery capacity and other electrical performance parameters after the battery is manufactured.

Generally, after passing the chemical capacity, and then going through strict screening and testing, the qualified battery cells can enter the mobile phone battery packaging process.

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