Characteristics and introduction of lithium batteries

　　1. Higher weight-to-energy ratio and volume-to-energy ratio;

　　2. The voltage is high, the voltage of a single lithium battery is 3.6V, which is equal to the series voltage of 3 nickel-cadmium or nickel-hydrogen rechargeable batteries;

　　3. It can be stored for a long time due to low self-discharge, which is the most prominent advantage of the battery;

　　4. No memory effect. Lithium batteries do not have the so-called memory effect of nickel-cadmium batteries, so there is no need to discharge lithium batteries before charging;

　　5. Long life. Under normal working conditions, the number of charge/discharge cycles of lithium batteries is far greater than 500;

　　6. It can be charged quickly. Lithium batteries can usually be charged with a current of 0.5 to 1 times the capacity, shortening the charging time to 1 to 2 hours;

　　7. It can be used in parallel at will;

　　8. Since the battery does not contain heavy metal elements such as cadmium, lead, mercury, etc., it has no pollution to the environment and is the most advanced green battery in the contemporary era;

　　9. High cost. Compared with other rechargeable batteries, lithium batteries are more expensive.

　　The internal structure of the lithium battery:

　　Lithium batteries usually have two appearances: cylindrical and rectangular.

　　The inside of the battery adopts a spiral wound structure, and a very fine and highly permeable polyethylene film separator is used to separate the positive and negative electrodes. The positive electrode includes a lithium ion collector composed of lithium and cobalt dioxide and a current collector composed of aluminum thin film. The negative electrode is composed of a lithium ion collector made of sheet carbon material and a current collector made of copper thin film. The battery is filled with an organic electrolyte solution. In addition, a safety valve and PTC components are installed to protect the battery from damage when the battery is abnormal and the output is short-circuited.

　　The voltage of a single-cell lithium battery is 3.6V, and the capacity cannot be infinite. Therefore, single-cell lithium batteries are often processed in series or parallel to meet the requirements of different occasions.