Updated September 2026: in 2021, after four years of smooth use, my MacBook Pro became unusually hot near the trackpad rather than the display, and when I opened the back panel I found the battery had swollen. I have rewritten it into a guide to spotting a swelling laptop battery early.
My MacBook Pro had worked well for over four years. Then it started behaving oddly. Under load it used to warm up near the display hinge, but now it was hot near the trackpad. Curious, I opened the back panel and found the battery had swollen.
What are the early signs of a swelling battery?
- Heat in unusual places, such as the palm rest or trackpad.
- A trackpad that clicks poorly or feels raised.
- A laptop that no longer sits flat, or a case that bulges or separates.
- Battery warnings such as "Service Recommended".
- Sudden drops in battery life.
Should you open the laptop to check?
It is safer not to. Opening the case risks pressing on or puncturing the battery. If you see signs of swelling, stop using and charging the laptop and take it to a service provider, who can inspect it safely.
Why do batteries swell?
Ageing lithium-ion cells can produce gas, especially after years of heat and constant full charging. It is more common in older laptops kept plugged in all the time.
How do you reduce the risk?
Keep the laptop ventilated, avoid using it on beds or cushions, keep macOS updated and use battery health settings that avoid holding a full charge. Replace the battery when its condition declines significantly.
What should you do immediately after finding swelling?
Back up if safe, shut down, unplug and keep the laptop on a hard surface away from anything flammable. Arrange a replacement promptly.
How long do laptop batteries last?
Typically several years, depending on use, heat and charging habits. Modern MacBook batteries are rated to keep up to 80 percent of capacity at 1,000 charge cycles. Mine lasted about four years before swelling, which is within the range of normal ageing for a heavily used machine.
Can the laptop be used again after replacement?
Usually yes. Check the trackpad and case for damage caused by the swelling.