We may not put much thought into smartphone batteries, but there's a lot going on inside them. As phones age, it becomes important to take proper care of the batteries inside them to ensure they don't swell. This was a common occurrence when smartphones first became popular—their batteries used to expand as they aged, leading to the back glass popping out. Over time and with technological advancements, manufacturers learned how to keep this problem under control. But it looks like Samsung may have an issue on its hand with batteries on its older phones swelling at a disproportionately high rate.