Stop
A swollen lithium-ion battery can leak, catch fire, or rupture. Stop using and charging it immediately, keep it away from heat and flammable materials, and take it to a proper battery recycling location rather than the trash.
Symptoms
- Battery case looks puffed, warped, or no longer sits flat
- Battery is difficult or impossible to insert into the tool or charger
- Case seams appear stressed or slightly separated
- Battery feels unusually warm even when not in use
Likely causes
- CommonInternal cell degradation from age or many charge cyclesSwelling is a known failure mode as lithium-ion cells age and can no longer safely hold their charge/discharge chemistry.
- PossiblePhysical damage from a drop or impactA cracked or dented cell can develop an internal short that generates gas.
- PossibleCharged or stored in extreme heat repeatedlyHeat accelerates the chemical breakdown that leads to swelling.
- Less commonManufacturing defect in the cellOccasionally a battery swells early in life due to a factory defect rather than misuse.
What to do
- Stop using and stop charging the battery immediately once you notice any swelling.
- Move it away from flammable materials and, if possible, to a fire-safe or metal container as a precaution.
- Do not attempt to puncture, open, crush, or continue charging a swollen battery under any circumstances.
- Do not throw it in household or recycling trash; lithium batteries require special handling.
- Take it to a battery or electronics recycling drop-off (many hardware and home improvement stores collect them) as soon as practical.
- Replace it with a new battery pack before resuming work with the tool.
Tools and parts
Replacement cordless drill batterySearch: “cordless drill replacement battery pack”
When to call a pro
This isn't a repairable situation; battery recycling centers and many retailers that sell power tool batteries accept swollen packs for safe disposal.
Safety
Stop
A swollen lithium-ion battery can leak, catch fire, or rupture. Stop using and charging it immediately, keep it away from heat and flammable materials, and take it to a proper battery recycling location rather than the trash.