Why does a lithium battery have a cycle life of 500 charges?

The vast majority of consumers believe that the lithium battery life is "500", charge and discharge for 500 times. If it is more than this number of times, the battery may be destroyed. Every time charge after the battery is out of power may not destroy the battery. Lithium battery has 500 times cycle life. It does not refer to the number of charge, but a cycle of charging and discharging.

A charge cycle means that all the power battery by full use empty, again by the empty into the full process, this is not the same as to charge., for example, a piece of lithium electricity on the first day only half of the battery, then charge for it. If so, the next day with half of the charge, the total charges down, it can only be counted as a charge cycle, instead of two. Often, therefore, may be charging after several times to complete a cycle. Each completed a charge cycle, battery capacity will reduce a little. The power decrease rate is very small, however, the high quality of battery charge cycle for many times, still retains the original capacity of 80%, a lot of lithium electric power products after two or three years later still use as usual. The li-ion battery life in the final and, of course, is still need to be replaced.

The so-called 500 times, is refers to the vendor in the constant depth of discharge (e.g., 80%), the number of rechargeable 625 times or so, to 500 charge cycles.

(80% * 625 = 500) (ignoring the lithium battery capacity reduction etc.)

Due to the various influence of real life, especially when charging the discharge depth is not constant, "500 charge cycles" can only be used as a reference battery life.

Life and its influencing factors

Lithium battery should generally put 300-500 times. Best to partial discharge of the lithium battery, rather than completely discharge, and try to avoid often completely discharge. Once the battery is off the production line, the clock began to move. Whether or not you use it, the service life of lithium-ion batteries are only in the initial years. Battery capacity decline is caused by the oxidation of internal resistance increases, this is the main cause of the battery capacity decline).Finally, the cell resistance can reach a certain point, although a full battery at this moment, but can not release already stored power battery.

Lithium battery aging speed is determined by the temperature and charging status.

Temperature charging 40% 100%

After a year of 0 ° C capacity by 98% a year after the capacity by 98%

After a year of 25 ° C capacity by 96% a year after the capacity by 96%

After a year of 40 ° C capacity by 85% a year after the capacity by 85%

After a year of 60 ° C capacity 75% three months after the capacity by 75%

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