We had a client bring in their laptop that had a battery that was starting to swell. On the left side is the swollen battery and on the right is the new battery that we replaced it out with. The swelling can also create pressure on the laptops trackpad and keyboard creating issues when typing or clicking and using your cursor.
The reason that batteries swell is due to the chemicals in them start to create gas when they come to their end of life. This can create noxious gases if punctured or even thermal events where they heat up and catch fire or even explode.
So if your battery is starting to swell, bring it in and let us perform a free evaluation on it and get this issue taken care of before it creates an even bigger problem