18650 lithium battery charge and discharge principle

The working principle of lithium-ion battery refers to its charging and discharging principle. When the battery is charged, lithium ions are generated on the positive electrode of the battery, and the generated lithium ions move to the negative electrode through the electrolyte. The carbon used as the negative electrode has a layered structure, and it has many micropores. Lithium ions that reach the negative electrode are embedded in the micropores of the carbon layer. The more lithium ions are embedded, the higher the charging capacity.

In the same way, when the battery is discharged (that is, the process of using the battery), the lithium ions embedded in the carbon layer of the negative electrode come out and move back to the positive electrode. The more lithium ions returned to the positive electrode, the higher the discharge capacity. The battery capacity we usually refer to refers to the discharge capacity.

It is not difficult to see that during the charging and discharging process of lithium-ion batteries, lithium ions are in a moving state from positive electrode → negative electrode → positive electrode. If we compare the lithium-ion battery to a rocking chair, the two ends of the rocking chair are the two poles of the battery, and the lithium-ion is like an excellent athlete, running back and forth at the two ends of the rocking chair. Therefore, the experts gave the lithium-ion battery a lovely name rocking chair battery.