Is there an app or a widget for Ubuntu 14.04 that would allow me to keep track of my laptop battery temperature?
So far I've found this thread but the question was never answered. It's an Inspiron 3521.
Not all laptops and batteries come with a temperature sensor for the battery. I know of no Dell that does.
You can purchase one of those laser/infrared thermometers and periodically point it at the battery though, and achieve the same general thing.