I have a new-ish Dell laptop, and its battery spontaneously started bulging. It was right after I took it away from my desk after many weeks of sitting on the charging dock. First I thought I had accidentally cracked it open, pushed it back together, and a couple minutes later it cracked open again on its own.

Fortunately this was a "work" computer, the IT crew fixed it in a jiffy. But I wonder if it uses a similar type of battery, looked like a thin black pillow when the tech took it apart.