Lithium-ion batteries are generally safe, but a failing one is one of the few everyday electronics problems that deserves genuine caution rather than a shrug. Knowing what to look for, and what to do the moment you spot it, matters more here than with almost any other device issue.
Physical warning signs to check for
- Swelling or a puffed-up case. A phone that no longer sits flat on a table, a laptop trackpad that's popped up on one side, or a battery that looks visibly rounded instead of flat are all signs of swelling — one of the clearest indicators of a battery that's degrading internally and building up gas.
- A device that feels unusually warm even when idle or not doing anything intensive, especially if this is new behavior for that device.
- A noticeable smell — a sweet or chemical odor near a device or battery is a sign of internal breakdown and should be taken seriously.
- Rapid, unexplained battery drain or a battery percentage that jumps erratically rather than declining smoothly.
- A battery health reading well below what's expected for the device's age, when checked through the device's built-in battery health tool.
What to do the moment you notice swelling
- Stop charging it immediately and unplug it from any charger.
- Don't puncture, bend, or press on the swollen area. A swollen lithium-ion battery is under internal pressure and physical damage can cause it to vent, smoke, or ignite.
- Move the device away from anything flammable and, if you have a safe outdoor space, consider keeping it there rather than inside until it can be dealt with, particularly for a laptop or larger device.
- Don't keep using it. Continued charge cycles on a swollen battery increase the risk of further swelling or failure.
- Contact the manufacturer or a certified repair service rather than attempting to remove the battery yourself, unless you're specifically experienced with battery handling — swollen cells are more prone to punctures or short circuits during removal.
Safe storage in the meantime
If you can't get a swollen device to a repair center or disposal point immediately, store it somewhere cool, away from direct sunlight, and away from anything flammable — a metal container or a fireproof bag designed for lithium battery storage is a reasonable precaution for a few days. Don't store it in a drawer full of paper, inside a car in the sun, or anywhere it can't be quickly moved if something changes.
Disposing of batteries and battery-powered devices properly
- Never put lithium-ion batteries in household trash or standard recycling bins. They can spark fires in garbage trucks and recycling facilities, which is a real and repeatedly documented cause of waste-facility fires.
- Use a dedicated battery or e-waste drop-off point — many electronics retailers, hardware stores, and municipal recycling centers accept batteries and battery-powered devices specifically for this reason.
- Tape over the terminals of a standalone battery before transporting it, to prevent it from shorting against metal in a bag or car.
- For a swollen or damaged battery, call ahead to your drop-off point — some facilities want damaged batteries brought in separately or handled with specific precautions rather than dropped in a standard collection bin.
If a battery is actively smoking, extremely hot, or leaking, treat it as an emergency rather than a repair task — move it away from anything flammable and, in the moment, prioritize safety over trying to save the device.
Quick safety checklist
- Check for swelling, unusual heat, or smell periodically on older devices.
- Stop charging immediately if you notice swelling, and avoid pressing or bending the area.
- Store a suspect device somewhere cool and away from flammable materials until it's dealt with.
- Never dispose of batteries in household trash — use a dedicated e-waste or battery drop-off point.
- Treat smoking, leaking, or extremely hot batteries as an emergency, not a repair task.