What do I do about a swollen battery in a phone or laptop?

Lithium cells swell when they degrade or are damaged, because gas builds up inside a sealed pouch. It is not a rare event and it is not a manufacturing scandal — old, hot or physically stressed cells do this. What makes it worth its own guide is that the intuitive responses are all wrong: pressing it back, prying it out, or putting it in the bin are each genuinely dangerous, and a swelling pack gives you plenty of warning if you know what to look for.

Safety

Step by step

1. Recognise the signs early.On a laptop: the trackpad stops clicking properly or sits proud, the base rocks on a flat table, or the case seams open. On a phone or tablet: the screen lifts at an edge, the back panel bulges, or the glass no longer sits flush. On a power bank: the case bows.
2. Stop charging it and stop using it now.Unplug it. Charging a swollen cell is the situation most likely to turn a slow problem into a fast one. Do not put it back on charge to get one more use out of it.
3. Power it down if you safely can.Shut it down normally. If it is hot to the touch, do not handle it more than necessary — put it down somewhere safe and leave it rather than fighting with it.
4. Get anything you need off it beforehand only if it is safe.If the device is cool and merely swollen, a short session to back up files is reasonable, unplugged and on a hard surface. If it is warm, do not — the data is not worth it, and a recent backup or the cloud copy usually has most of it anyway.
5. Move it somewhere it cannot start a fire.A hard non-flammable surface — a tiled floor, a metal tray, a paving slab outside under cover — away from paper, curtains, bedding and furniture. Not in a drawer, not in a bag, not on a sofa, not in a car.
6. Never puncture, squeeze, bend or lever it.Not with a screwdriver, not with a knife, not by clamping the laptop shut. Breaking the pouch exposes the contents to air and a fire follows immediately. This is the single most important rule and it applies even to a pack that seems cool and stable.
7. Take it for proper disposal.Household waste and recycling centres have battery points and accept damaged cells; say what it is when you arrive. Many phone and computer repair shops will also take one. It must not go in any household bin or recycling box.
8. Have the device assessed rather than assuming it is scrap.A swollen battery in an otherwise good laptop is often a straightforward professional replacement, and the rest of the machine is usually undamaged. Ask a repairer; do not open it yourself.
9. Escalate if it is hot, hissing or smoking.Leave the room, close the door, ventilate if you can do so safely, and call the fire service. Lithium fires produce toxic smoke and reignite. Do not carry a burning or venting device through the house.

Tips

• Check power banks and old spare phones occasionally — packs that sit unused for years in a drawer are a common place for this to happen unnoticed.
• Heat is the main accelerant. A laptop that lives on a duvet, or a phone left on a car dashboard in summer, is being pushed towards this outcome.
• If a device is under warranty, report the swelling rather than dealing with it yourself. Manufacturers take it seriously and it is often covered.

Common mistakes

• Clamping the laptop shut to flatten the bulge — It compresses a gas-filled pouch. That is the mechanism that causes an internal short and ignition, and it can happen with no further warning.
• Putting it in the bin, the recycling box or a drawer — A bin lorry compacts it, which is exactly the failure mode described above. A drawer simply puts a fire risk somewhere unwatched and inside the house.

If it doesn't work

Questions people ask