Lithium battery life is not calculated by years, but by cycle. The life of lithium battery is "500 times", which refers to a charging and discharging cycle rather than the number of times of charging.

　　At present, mobile phones use lithium batteries. Most lithium batteries have been cycled for about 500 times, which means that from 0 to 100 is a cycle (when the cycle reaches 100, it is a cycle). After 500 times, the mobile phone battery has weakened, the internal resistance of the battery has become larger, and the activity of the internal chemical elements has decreased, entering a rapid consumption stage.

　　A charging cycle means that all the power of the battery goes from full to empty, and then from empty to full, which is not the same as charging once. For example, a lithium battery uses only half of its power on the first day, and then fully charges it. If it is still the case the next day, that is, use half of it to charge, and charge it twice in total, which can only be counted as one charging cycle, not two.

　　Therefore, it is usually possible to complete a cycle after several charges. After each charging cycle, the battery capacity will be reduced a little. However, this power reduction is very small. After several cycles of charging, high-quality batteries will still retain 80% of their original capacity. Many lithium battery power supply products will still be used after two or three years.

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