Working principle of lithium-ion batteries
As everyone knows, the positive electrode material of a lithium-ion battery is lithium cobalt oxide, and the negative electrode is carbon.
The working principle of a lithium-ion battery refers to its charging and discharging principle. When the battery is charged, lithium ions are generated at the positive electrode. These lithium ions then move through the electrolyte to the negative electrode. The carbon used as the negative electrode has a layered structure with many micropores. The lithium ions that reach the negative electrode are embedded in these micropores. The more lithium ions embedded, the higher the charging capacity.
Similarly, when a battery is discharged (i.e., when we use the battery), lithium ions embedded in the carbon layer of the negative electrode are released and move back to the positive electrode. The more lithium ions return to the positive electrode, the higher the discharge capacity. The battery capacity we usually refer to is the discharge capacity.
It's easy to see that during the charging and discharging process of a lithium-ion battery, lithium ions are in a state of motion, moving from the positive electrode to the negative electrode and back to the positive electrode. If we figuratively compare a lithium-ion battery to a rocking chair, with the two ends of the chair representing the battery's electrodes, the lithium ions are like excellent athletes running back and forth between the two ends. Therefore, experts have given lithium-ion batteries another endearing name: rocking chair batteries.
The assembly process of lithium-ion batteries
The manufacturing process of lithium-ion batteries is very rigorous and complex, and only a few of the important processes can be briefly introduced here.
(1) Pulping
Specialized solvents and binders are used to mix the powdered positive and negative electrode active materials separately. After being stirred at high speed until homogeneous, a slurry of positive and negative electrode materials is formed.
(2) Coating
The prepared slurry is evenly coated onto the surface of a metal foil, dried, and then used to make positive and negative electrode sheets.
(3) Assembly
The positive electrode sheet, separator, negative electrode sheet, and separator are arranged in the order from top to bottom and wound to form the battery core. Then, the battery assembly process is completed by injecting electrolyte and sealing. The finished battery is then produced.
(4)Chemification
The finished batteries are tested using specialized battery charging and discharging equipment. Each battery is inspected, and qualified finished batteries are selected for shipment.
