If your phone’s screen is lifting away from the frame, the back looks bulged, or the phone rocks when you set it on a flat table, treat it as a swollen battery until you’ve shown otherwise. Stop charging it, stop carrying it against your body, and have it serviced. Most phone problems on this site can wait a day while you test things, but this is the one where waiting and watching is the wrong plan, because a swollen lithium-ion battery is a fire risk, not just a cosmetic flaw.
What You’re Actually Looking At
Lithium-ion batteries can swell when gas builds up inside the sealed pouch. Age, repeated heat, a failing cell, physical damage, and poor-quality chargers can all contribute, and the result is a battery that takes up more room than it did when the phone was new. Inside a tightly built phone there’s nowhere for that extra volume to go, so it pushes outward on the nearest thing, which is usually the screen or the back panel. That’s why the first sign is often a thin gap along the edge of the screen, a seam that has started to open, or a case that suddenly fits too tightly.
Apple’s own iPhone battery safety guidance lists swelling among the signs of a damaged battery and says a battery with visible damage shouldn’t be used. Other manufacturers say much the same. The reason is simple: a swollen cell has already been damaged, and it can’t be reliably restored.
The 30-Second Look-Only Check
The key word is look. Don’t press on the phone to see what happens, and don’t try to flatten it.
Set the phone on a hard, flat table with the screen facing up. Bring your eyes down level with the surface and look at the phone from the side. A healthy phone sits flat. A phone with a swollen battery may rock slightly, because the back is no longer perfectly level, or may sit on a visible hump. Next, look at the seam where the screen meets the frame all the way around. A narrow, even line is normal. A gap that’s wider in one spot, a corner that looks raised, or an edge you can see light through is not.
Turn the phone over and check the back panel for a bulge or a ripple in the glass. Then try your case, if you use one. A case that has always fit and now won’t snap on, or pops off by itself, is one of the most common first clues people notice.
Sort What You Found Into One of Three Groups
This is the part that tells you how fast to move.
If you see a faint gap or a slight rock but the phone otherwise behaves normally and stays cool, that’s a likely swollen battery that needs service soon. Switch the phone off, stop charging it, and book the repair this week.
If the screen is visibly lifting, the back is clearly bulged, or the phone has become hard to close up in a case, the swelling is advanced. Switch it off, don’t charge it, and get it to a technician within a day or two. Until then, keep it somewhere it won’t be pressed or knocked.
If the phone is hot when you haven’t been using it, smells sweet or chemical, hisses, smokes, or is changing shape while you watch, that is an emergency. Move away from it and leave it alone. Don’t pick it up if you can avoid it, and call your local emergency number. Don’t try to put it out with water or carry it outside by hand if that means getting close to it.
What To Do While You Wait for Service
Power the phone off, unplug it, and put it on a hard, non-flammable surface such as a tile floor or a stone countertop, away from paper, bedding, and other devices. Don’t leave it charging overnight and don’t keep it in a pocket, bag, or bed. Don’t press the bulge, don’t use heat on it, and don’t open the phone yourself. The battery is held in with strong adhesive and prying around a swollen cell is how many fires start.
At the repair counter, tell them it’s a swollen battery before you hand it over, since they’ll want to handle it differently from an ordinary phone. A battery replacement is a standard repair, and our guide to deciding between repairing and replacing can help you weigh it against the age and value of your phone. A swollen battery also shouldn’t go in the household trash. Most electronics shops and recycling centers accept lithium-ion batteries.
Warning Signs That Often Come First
Swelling rarely arrives out of nowhere. A battery that is heading that way often shows its age in smaller ways first, such as a percentage that drops suddenly and unpredictably, a phone that gets noticeably hot, or charging that slows to a crawl as the phone warms up. None of these mean your battery is swelling. Charging slowdown is usually a protective feature and a jumpy percentage is usually just a worn battery. But if you’ve been seeing them and then notice a gap or a bulge, that history makes swelling more likely. Even a phone that seems to lose charge while completely off isn’t a swelling sign by itself, but it’s one more reason to check the battery’s health.
FAQ
How can I tell if my phone battery is swollen?
Set the phone on a flat table and look at it from the side. A swollen battery can make the phone rock, push the screen away from the frame, create a gap along the seam, or bulge the back panel. A case that no longer fits is another common sign. Look only; don’t press on the phone.
Is it safe to keep using a phone with a swollen battery?
No. A swollen battery has already been damaged, and swelling raises the risk of overheating and fire. Switch the phone off, stop charging it, and have the battery replaced by a qualified technician.
Why is my phone screen lifting up?
The most common cause is a swollen battery pushing the screen outward from underneath. Less often, a hard drop or a poor-fitting replacement screen can loosen the adhesive and open a gap. Because a swollen battery is the safer assumption, treat the phone as one until a technician says otherwise.
What should I do if my swollen phone gets hot or starts smoking?
Move away from it immediately, don’t touch it, and call your local emergency number. Don’t use water on it or try to carry it by hand if that means getting close.
Can a swollen battery go back to normal?
No. Once the cell has swollen, the damage is permanent. Pressing on it, heating it, or leaving it on a charger doesn’t fix it and can make it worse. The battery needs to be replaced.