LR521 battery.Can lithium-ion batteries only be charged and discharged 500 times?

　　I believe the vast majority of consumers have heard that the lifespan of lithium batteries is "500 times", with 500 charges and discharges. Beyond this number, the battery will "die". Many friends, in order to extend the lifespan of the battery, charge it every time the battery is completely depleted. Does this really have an effect on extending the lifespan of the battery? The answer is no. The lifespan of a lithium battery is "500 times", which refers not to the number of charges, but to a charging and discharging cycle.

　　A charging cycle means the process of charging the battery from full to empty, and then from empty to full, which is not equivalent to charging once. For example, a lithium-ion battery only uses half its capacity on the first day, and then fully charges it. If this continues the next day, that is, charging half of it and charging it twice in total, it can only be counted as one charging cycle, not two. Therefore, it may usually take several charges to complete a cycle. Every time a charging cycle is completed, the battery capacity will decrease slightly. However, the reduction in battery capacity is very small. After multiple cycles of charging, high-quality batteries still retain 80% of their original capacity, and many lithium-ion powered products are still in normal use after two to three years. Of course, lithium-ion batteries still need to be replaced after their lifespan reaches the end.

　　The so-called 500 times refers to the manufacturer achieving about 625 charging cycles at a constant discharge depth (such as 80%), reaching 500 charging cycles.

　　(80% * 625=500) (ignoring factors such as reduced lithium battery capacity)

　　Due to various impacts in real life, especially the discharge depth during charging is not constant, "500 charging cycles" can only be used as a reference for battery life.

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