A lithium-ion (or li-ion) battery is a rechargeable battery that uses the recombination of Lithium ions with their missing electron to generate electricity, and the reverse of this process to recharge1.
Lithium-ion batteries can be considered a family of battery technologies including:
- Traditional lithium-ion
- Lithium polymer
- Lithium-iron phosphate
ERROR: tbl-basic-properties REF NOT FOUND shows some of the basic properties of Lithium-ion batteries.
Lithium-ion batteries have a self-discharge rate which is 10 times less than NiMH batteries2.
The common way to charge a Lithium-ion battery is to follow these steps:
- The pre-charge stage, which is only applicable if the battery is really flat (less than 2.8V). The battery is charged with a constant-current, usually 10% of current used in the next stage (sometimes called the fast charge).
- Charge the battery with a constant current (CC), at a rate of around 0.5-1C3.
- Once the battery reaches a certain voltage (typically 3.9-4.2V), we switch from CC charging to CV charging. We maintain this voltage while the current begins to decrease.
- Stop charging once the current drops to approximately 0.1C.
It is not healthy to store a Lithium-ion battery for a long time at 100% charge. Storing them for a long time at 40-50% capacity appears to be provide the best lifetime4.
1C is the current required to drain the battery in 1 hour, e.g. for a 500mAh battery, 1C is 500mA. Most battery charger ICs will automatically perform the above steps for you.
Pre-charge can also been confused with the pre-charge step that occurs in the manufacturing process after the cells have been filled with electrolytes.
TI’s BQ Range
Texas Instruments sells a large number of battery charger ICs under the prefix
BQ. Some are I2C controllable, others are standalone. Some have hot/cold temperature monitoring and others (typically with a
J after the numerical code in the part name) have JEITA temperature monitoring.
- Battery short
- Constant current (CC)
- Constant voltage (CV)
Richtek RT9481, RT9485
RT9485 has an on-board MCU.
Battery University (2021, Oct 25). BU-409: Charging Lithium-ion. Retrieved 2023-08-13, from https://batteryuniversity.com/article/bu-409-charging-lithium-ion. ↩︎
Battery University (2021, Oct 21). BU-702: How to Store Batteries. Retrieved 2023-08-13, from https://batteryuniversity.com/article/bu-702-how-to-store-batteries. ↩︎
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