Ordinary lithium-ion batteries have a small expansion when charging:
A small amount of gas is generated inside the battery during charging and is generally absorbed during discharge. If the charging current is too large, the overcharging will increase the gas generation and increase the internal pressure of the battery to cause swelling. A slight bulging of the battery is allowed. Avoid overcharging to reduce the bulging phenomenon.
The chemical properties of lithium are very active and easy to burn. When the battery is charged and discharged, the inside of the battery continues to heat up. The gas generated during the activation process expands, the internal pressure of the battery increases, and the pressure reaches a certain level. If the outer casing is scratched, it will rupture. It causes liquid leakage, fire, and even explosion, so it is absolutely important to ensure its safety performance.
You should say a POLYMER Li-ion battery, a lithium-ion polymer battery. This kind of battery will cause a big expansion. Even if it is not used, it will be put aside!
The lithium polymer battery is packaged in aluminum plastic film. During the use of the polymer lithium ion battery (including the charging part), the organic electro-hydraulic gas generates gas, which causes the battery to swell. Generally, some inferior lithium batteries or damage during production and use will cause the lithium battery to swell.