What Is a Li-Ion / LiPo Battery?
Li-Ion and LiPo are high-energy-density rechargeable (secondary) batteries based on lithium chemistry. They store far more energy than other chemistries at the same weight.
Li-Ion vs LiPo Difference
Both are lithium-based. Li-Ion is usually a hard metal cylindrical cell (e.g. 18650). LiPo is a thin, flexible pack with a gel/polymer electrolyte; it suits slim devices and drones.
| Property | Value |
|---|---|
| Cell voltage | ~3.7V nominal |
| Energy density | High |
| Protection | BMS essential |
BMS (Protection Circuit)
Lithium cells are sensitive to overcharge, over-discharge and short circuit. A BMS (Battery Management System) monitors the cell voltage and protects these limits; in multi-cell packs it balances the cells. Use without a BMS carries a fire risk.
Charging Logic
Lithium batteries are charged with the "constant current first, then constant voltage" (CC-CV) method, with a special charger IC. Careless feeding is dangerous.
Where Is It Used?
Phones, laptops, drones, electric vehicles, power banks and every device needing high energy/light weight.
Storage and Swelling
If lithium batteries will be stored for a long time, they should be kept at ~50% charge in a cool place, not fully charged or fully empty. A swelling LiPo indicates gas forming inside and is dangerous; it must not be punctured or charged and should be disposed of safely.
Common Mistakes
- Use without a BMS: an unprotected lithium battery is an explosion/fire risk.
- Wrong charging: charging with a method other than CC-CV is dangerous.
- Physical damage: a punctured/swollen LiPo must be taken out of use immediately.
Frequently Asked Questions
Which is better, Li-Ion or LiPo?+
Is a BMS a must?+
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