How lithium-ion batteries work

- Aug 28, 2018-

A lithium ion battery is a general term for a battery in which a lithium ion intercalation compound is used as a whole material. A lithium battery in which a carbon material is used as a negative electrode and a lithium-containing compound is used as a positive electrode, in the process of charge and discharge, there is no metal lithium, and only lithium ions, which is a lithium ion battery. When the battery is charged, lithium ions are generated on the positive electrode of the battery, and the generated lithium ions move through the electrolyte to the negative electrode. The carbon as the negative electrode has a layered structure, and it has many micropores. The lithium ions reaching the negative electrode are embedded in the micropores of the carbon layer, and the more lithium ions are embedded, the higher the charging capacity. Similarly, when the battery is discharged (ie, the process we use 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 return to the positive electrode, the higher the discharge capacity. What we usually call battery capacity refers to the discharge capacity. During the charge and discharge process of Li-ion, lithium ions are in a state of motion from positive electrode to negative electrode to positive electrode. The Li-ion Batteries are like a rocking chair. The two ends of the rocking chair are the two poles of the battery, and the lithium ion runs back and forth like an athlete in the rocking chair, so Li-ion Batteries is also called a rocking chair battery.

Generally, the charging current of the lithium battery is set between 0.2C and 1C. The higher the current, the faster the charging, and the greater the heating of the colleague battery. Moreover, an excessively large battery is charged, and the capacity is not sufficient because the electrochemical reaction inside the battery takes time. Just like pouring beer, if it is too fast, it will produce bubbles, but it will not be full.

In the charging and discharging process of a lithium ion battery, it is a process of intercalating and deintercalating lithium ions. Lithium-ion batteries generally use lithium cobaltate as the positive electrode and carbon as the negative electrode. The electrolyte is filled in the middle to form a channel for ion free, and the separator is used to separate the positive and negative electrodes to prevent short circuit. When charging, lithium ions migrate from the lithium cobaltate due to the electric field, and pass through the pores in the separator in the electro-hydraulic solution, and reach the negative electrode and react with carbon to form lithium carbide; in contrast, the lithium ion returns to the positive electrode. It is the charging and discharging process of a lithium ion battery.