1. Memory effect
This is a common phenomenon with nickel-metal hydride (NiMH) rechargeable batteries. Specifically, if the battery is used without being fully charged, its capacity will drop significantly, and it won't fully charge even later. Therefore, an important way to maintain NiMH batteries is to only start charging them after they are completely depleted, and to only use them after they are fully charged. The memory effect of commonly used lithium-ion batteries is negligible.
2. Fully charge and fully discharge.
This applies to lithium-ion batteries.
Complete discharge refers to the process of draining the power of an electronic device, such as a mobile phone, by adjusting it to the lowest power level until the phone automatically shuts down.
A full charge refers to the process of connecting a fully discharged smart device, such as a mobile phone, to a charger until the phone indicates that it is fully charged.
3. Over-discharge
This also applies to lithium-ion batteries. Even after a complete discharge, a small amount of charge will remain inside a lithium-ion battery, but this charge is crucial to the battery's activity and lifespan.
Over-discharge: After a complete discharge, if other methods are used to continue using the battery, such as forcibly turning the phone back on or connecting the battery to a small light bulb to consume the remaining power, this is called over-discharge.
It will cause irreversible damage to lithium-ion batteries.
4. Protection chip
Lithium-ion batteries have extremely strict requirements on the current and voltage applied during charging and discharging. To protect the battery from damage due to abnormal external electrical environments, a chip is installed inside the battery to manage its operating state. This chip also records and calibrates the battery capacity. Even counterfeit mobile phone batteries nowadays don't skimp on this crucial protection chip; otherwise, they wouldn't last long at all.
