MacBook Battery Swollen? Stop Charging It — Here's What to Do Next

Most swollen MacBook batteries announce themselves through the trackpad. It starts clicking strangely, sits raised above the deck, or stops clicking at all — because the battery cells directly underneath it are inflating and pushing up. If that sounds like your machine, or your MacBook's bottom case is bulging, rocking on a flat table, or the case seams are opening up, read this before you plug it in again. A swollen battery is a manageable problem if you handle it right and a genuinely dangerous one if you don't.

How to Recognize a Swollen Battery

• Trackpad misbehaving: raised, stiff, clicking on its own, or refusing to click. This is the number-one early sign, because on most MacBooks the battery sits directly under the trackpad.
• Bottom case bulging or the laptop wobbling on a flat surface when it used to sit flush.
• Keyboard deck lifting or flexing upward, sometimes with keys sitting unevenly.
• Case seams separating or the lid no longer closing flush against the body.
• Battery health warnings in macOS ("Service Recommended" under System Settings → Battery), often paired with rapid discharge.

Any one of these is enough to warrant a look. Two or more together is close to a certainty.

Why Lithium-Polymer Cells Swell

MacBook batteries are lithium-polymer pouch cells — flat foil envelopes rather than rigid metal cans. As a cell ages, its electrolyte slowly breaks down through normal charge cycling, and that decomposition produces gas. Heat, constant 100% charging, and simple age all accelerate it. In a rigid cylindrical cell that gas has nowhere to go; in a pouch cell it inflates the envelope like a balloon. That's what's pressing on your trackpad.

Here's the critical part: the gas is flammable, and the inflated pouch is what's containing it. A swollen cell sitting undisturbed is reasonably stable. A swollen cell that gets punctured, creased, or crushed can go into thermal runaway — a self-accelerating chemical reaction that burns hot, fast, and can't be smothered like a normal fire because the cell supplies its own oxidizer.

What to Do Right Now

1. Stop charging it. Charging pushes more energy into failing cells and actively worsens the swelling. Unplug the charger and power the machine down.
2. Don't press on the bulge. Don't try to "flatten" the trackpad, don't stack books on the laptop, don't force a warped lid closed.
3. Don't puncture or pry. Never poke the battery to "deflate" it — that's the one action most likely to cause a fire. This also means don't attempt a DIY battery removal: MacBook packs are glued down, and prying a swollen pouch off adhesive is exactly the puncture-and-crease scenario to avoid.
4. Don't fly with it. Airlines and the FAA prohibit visibly damaged or swollen lithium batteries on aircraft for good reason. If you have a trip coming, get it serviced first.
5. Store it safely until service. Cool, dry, away from anything flammable — a tile floor, a metal shelf, a garage away from fuel. Not a hot car, not under a pile of papers, not in a backpack being tossed around.

Why Swollen Batteries Are a Shop Job

This is one repair where we tell even confident DIYers to sit it out, and not to protect our bottom line. MacBook batteries are bonded to the top case with strong adhesive. The safe removal process involves fully discharging the pack, working solvent under the cells or using dedicated release methods, and easing each pouch off without flexing it — with a fire-safe container within reach the entire time. We do this on an open bench with the board's power paths verified before the new pack goes in, because swelling occasionally accompanies charging-circuit faults that would just wreck a new battery too. A proper job also means the old pack goes out through hazardous-material recycling, not a household trash can, where compacted swollen cells start real fires.

Once the new battery is in, the trackpad almost always returns to normal on its own — the click mechanism was being pressed from below, not broken. If the case or trackpad was permanently deformed by the pressure, we'll show you exactly what's affected and what fixing it involves.

Your Data Is Fine

Worth saying clearly: battery swelling does not damage your files. Your data lives on the SSD, a separate component the battery doesn't touch. A battery replacement leaves your system exactly as you left it. If the machine still boots, make a Time Machine backup before service as a routine precaution — the same advice we give in our MacBook won't turn on guide. And if your battery swelled after a spill (liquid damage can corrode the battery circuitry), see our liquid damage first-aid guide — mention the spill when you bring it in, because it changes what we inspect.

Geek Guys has replaced MacBook batteries — including plenty of swollen ones — since 2016 at our Haddonfield shop. Walk it in during shop hours, or if you're not local, our mail-in service can take it (we'll walk you through packing a swollen-battery machine safely when you call). Call for an assessment.

FAQ

How do I know if my MacBook battery is swollen?

The trackpad usually tells you first — raised, clicking oddly, or not clicking — because the battery sits right beneath it. Bulging bottom case, lifting keyboard deck, separating seams, or a lid that won't close flush are the other classic signs.

Is a swollen MacBook battery dangerous?

Treated carelessly, yes. The bulge is flammable gas inside the pouch cell. Left alone it's reasonably stable; punctured or crushed it can go into thermal runaway. Don't press it, don't poke it, don't fly with it.

Can I keep using my MacBook with a swollen battery if it's plugged in?

No. Charging worsens the swelling, and the growing pressure can crack the trackpad and deform the case. Power it down, unplug it, and store it cool and away from flammables until service.

Will I lose my data when the battery is replaced?

No. Data lives on the SSD, which battery replacement doesn't touch. Back up first if the machine boots, as with any service, but the swelling itself doesn't harm your files.