What Causes Battery Swelling and Can a Swollen Battery Be Used?

No. A swollen battery should not continue to be used. Swelling, or bloating, means gas has built up inside the cell from unwanted chemical reactions, and it is an early warning that the cell is no longer stable.

Why gas forms

When a lithium-ion cell is overcharged, exposed to high temperatures, or aged well beyond its useful life, the electrolyte decomposes and releases gases such as carbon dioxide, methane and hydrogen. Even mild manufacturing impurities or a micro internal short can slowly generate gas over time.

Why it is a safety concern

The pressure pushes the case outward. In a pouch cell the laminate film balloons; in a rigid pack this pressure can distort the device, crack the housing or strain cell connections. Continued charging or discharging raises the risk of rupture, leakage or thermal runaway.

Safe handling and prevention

Stop using the pack and recycle it through a qualified battery handler. Do not puncture, heat or attempt to open the cell. Prevent swelling by charging within the rated voltage range, avoiding high-temperature operation and replacing aged packs before they distort.