One day back in October I was setting my Mid-2015 MacBook Pro down on a flat surface and noticed it was rocking back and forth.
First thought, WTF?
I pick it up and hold it on edge and gaze across the bottom surface as one does to check for flatness. And sure enough there’s a bulge in the aluminum back of the MacBook.
This is not good. So I start removing screws from the back and eventually the back pops loose as the pressure is released from the bulging batteries.
These are pictures of the swollen batteries. Notice how they are not flat anymore. Batteries that look like this are in severe danger of exploding or catching fire and melting your aluminum MacBook into a molten pool.
I can’t stress this enough. If you have batteries that look like this on any device, get rid of them immediately.
Luckily there was no sacrificing of the MacBook to the fire gods, but I did end up replacing the batteries with a new set from iFixit (love those guys) for a little over $100. Apple charges around $200 for battery replacement.
One thing to mention, while replacing the batteries yourself is about half the cost of taking it to the Apple Store, it is not a trivial task and basically requires disassembling the entire laptop until it looks like this.
Fortunately everything went back together with no extra screws left over and it’s working like it should now.
Not sure why they swelled other than being a few years old, but they were no where near their cycle limit. Just glad I didn’t have a battery fire on my hands.