1. Avoid exposure to extremely high and low temperatures, especially during charging. If your phone gets hot on the charger, remove it. Similarly, avoid charging in extremely cold conditions. Extreme temperatures can accelerate the degradation of almost all battery components. As a guideline, do not charge if the temperature exceeds 10-35°C.
2. Batteries hate being too full or too low. Ideally, you should never charge them above 80% or discharge them below 20%, as exceeding either limit will stress the lithium-ion battery and degrade it. If you want a fully charged battery, continue charging it until it reaches 100%, then immediately remove it from the charger.
3. If possible, avoid fast charging and discharging. Fast chargers may seem convenient, but the high current will heat up and degrade the battery faster than slow charging. The same applies to high discharge rates; power-intensive applications are detrimental to your battery and will shorten its lifespan.
Finally, avoid using or storing lithium-ion batteries in humid environments and prevent mechanical damage such as puncture.
Lithium-ion batteries function by the migration of ions between the positive and negative electrodes. Theoretically, under this mechanism, lithium-ion batteries can operate indefinitely. However, over time, battery performance degrades due to the increased temperature associated with charge-discharge cycles and battery aging. Manufacturers take a conservative estimate, considering the cycle life of most commercially available lithium-ion batteries to be between 300 and 500 cycles.
However, assessing battery lifespan by the number of cycles is meaningless because deep discharge can occur during the discharge process, and there is no clear standard to characterize the number of cycles. Besides using cycle counts, some device manufacturers suggest using date stamps to indicate battery replacement time, but this method ignores environmental conditions during use and is also unreliable. A battery may fail within its service life due to overloading or unsuitable temperature conditions, but most battery packs have a lifespan far exceeding the specified time.
Battery performance is characterized by its capacity, which is also an important battery safety indicator. While internal resistance and self-discharge can affect battery capacity, their impact on the ultimate lifespan of new lithium-ion batteries is negligible.
