“Cell phone batteries must be used until the automatic shutdown before charging, otherwise they will 'hold a grudge' the shorter they are used!” “All-night charging will make the battery 'hold up', and it will be scrapped in two years!” “Fast charging is very hurtful to the battery, always use slow charging in order to extend the life of” ...... these lithium batteries on the ‘voice of experience’, are you also convinced?
In fact, many of the widely circulated “battery maintenance tips” are essentially the cognitive inertia of the nickel-cadmium battery era, or misunderstood technical details. In particular, the concept of “memory effect” has long been proven by scientific experiments to be irrelevant to lithium batteries. In this article, we will dismantle several core misconceptions about lithium batteries, and solve your doubts with scientific principles.
The 5 most common misconceptions about lithium batteries, broken down one by one!
Based on the misunderstanding of the “memory effect”, there are many misconceptions about lithium batteries. The following are the most typical 5 major misconceptions, combined with scientific and experimental data one by one to dispel the rumors:
Myth 1: “Lithium batteries must be fully discharged before charging or they will be ‘passivated’”
Truth: Lithium batteries are prohibited from being fully discharged, and deep discharging (<10% charge) will instead accelerate the damage.
In the era of Ni-Cd batteries, “periodic complete discharge” is to avoid the buildup of crystalline layers; however, the negative electrode of lithium batteries is graphite, whose layered structure allows lithium ions to freely embedded / dislodged, and there is no “passivation There is no “passivation” problem. On the contrary, if the lithium battery is discharged for a long period of time until the power is exhausted (automatic shutdown or even lower), the lithium ions on the surface of the negative electrode will not be able to be embedded in time and form “dead lithium” (lithium metal particles), which cannot participate in the subsequent charging and discharging reactions, leading to a Permanent loss of battery capacity.
Correct practice: the best charging range of lithium batteries is 20%-80% (daily use), occasionally full (100%) or to 30% charging does not have much influence However, try to avoid charging below 20% or above 90% for a long time.
Myth 2: “Charging all night will ‘break’ the battery and shorten its life”
Truth: Modern lithium batteries have a BMS (Battery Management System) that addresses the issue of “overcharging” and the effects of overnight charging are overstated.
Early Ni-Cd batteries had no overcharge protection, and prolonged charging could lead to electrolyte boiling, battery expansion, or even explosion; however, the BMS of Li-ion batteries cuts off the main charging circuit after the charge reaches 100%, and only retains a tiny current ( However, the BMS of Li-ion battery will cut off the main charging circuit after the battery reaches 100%, and only keep a small current (“trickle charge”) to maintain the voltage stable. At this time, the battery is in a “full standby” state, and will not continue to enter a large amount of electricity.
Experimental data show that: in 25 ℃ environment, lithium batteries are stored at full charge for 24 hours, the capacity degradation is only about 0.01%; even if they are stored continuously for 7 days, the degradation is also controlled within 0.1% (much lower than the impact of high temperature or deep discharge). The real harm to the battery is long-term full-charge storage + high temperature environment (such as summer car sun exposure), at this time the electrolyte decomposition accelerated, which will lead to a significant decline in capacity.
The right thing to do: there is no need to be anxious about charging throughout the night, but try to avoid prolonged exposure to high temperatures (e.g., above 35°C) while fully charged.
Myth 3: “Fast charging hurts the battery, always use slow charging to extend the life”
Truth: Fast charging itself doesn't hurt the battery, high temperatures are the culprit; reasonably designed fast charging technology can balance speed and longevity.
The charging speed of Li-ion batteries is determined by the “charging current”, and the essence of fast charging (e.g. 67W, 120W) is to shorten the charging time by increasing the current. According to the charging and discharging curves of Li-ion batteries, the lithium ion migration rate is faster in the early stage (0%-80% of the charge), and high current charging will not significantly affect the structure; however, in the later stage (80%-100%), the current needs to be reduced in order to avoid the accumulation of lithium ions (lithium precipitation).
What really hurts the battery is the rise in temperature (>45°C) caused by resistance heating during fast charging. Battery aging is only accelerated if you use a non-original fast-charging head (high internal resistance and high heat generation), or if you play a large game while charging (both the battery and the processor heat up at the same time).
The “memory effect” of lithium batteries has long been disproved, and those “maintenance tips” that have been passed down for many years are mostly the cognitive inertia of the nickel-cadmium battery era or a misunderstanding of the technical details. It is more important to understand the chemical logic of lithium batteries (the migration law of lithium ions, the tolerance boundary of the material) than to blindly follow the “old experience”.
Post time: Jun-10-2025