How to tell if a battery is swollen
A lithium-ion battery swells when gas builds up inside it, usually from age, heat, damage or a faulty charger. In a phone, there's nowhere for it to go, so it pushes outwards:
- the screen lifts away from the frame, often at one edge, or you can see a gap;
- the back bulges, or the phone rocks on a table;
- the screen shows pressure marks, or touch stops working properly in one area;
- the phone doesn't sit flat in its case any more.
A swollen battery is damaged and can catch fire. It's not something to keep using until the weekend.
What to do now
- Unplug it if it's charging, and don't charge it again.
- Turn it off if it's safe to handle.
- Take it out of its case so the pressure isn't trapped against the screen or back.
- Put it somewhere cool and dry, away from heat and anything flammable: a bare tiled floor or a metal tray, not a bed, a couch or a car.
- Don't put it in your pocket or bag on the way to the shop if it's warm. Carry it in something non-flammable.
- Get the battery replaced as soon as you can.
What never to do
- Don't press the screen back down or squeeze the phone. Pressure on a swollen cell can puncture it.
- Don't puncture or cut it to "let the air out". Damaged lithium cells can start burning in seconds.
- Don't keep charging it to get the last day out of it.
- Don't freeze it or heat it. Neither fixes a swollen cell.
- Don't put it in the rubbish or the recycling bin. Batteries in bins start fires in garbage trucks and at waste facilities; the Queensland Government asks everyone not to bin them.
Can my data be saved?
Usually, yes. Swelling damages the battery, and sometimes the screen it pushes against, but your data is stored on the phone's main board. With a new battery, most phones start normally. If the screen has been damaged by the swelling, that can be replaced too.
Why batteries swell (and how to avoid it)
- Age: after many charge cycles, every lithium-ion battery wears.
- Heat: a phone left in a hot car, on a sunny dashboard or under a pillow while charging.
- Cheap or damaged chargers and cables that don't regulate power properly.
- Physical damage from a drop that dented the battery.
Use a good charger, keep the phone out of the heat, and replace the battery once its health drops (see iPhone battery health or Samsung and Oppo battery health).
Disposing of a swollen battery
If you're replacing the phone rather than repairing it, it still mustn't go in a bin. Phones and batteries can be recycled for free: see where to recycle an old phone in Brisbane. Tell the drop-off point that the battery is swollen, so it can be handled separately.
Sources
- Queensland Fire Department: Lithium-ion battery safety
- Queensland Government: Don't bin your batteries
- Fire and Rescue NSW: What should I do if my battery is smoking or on fire?
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