I had a similar issue. Could you run
top on the terminal? If I can't help you, that will make the diagnosis easier for other people.
The top command will show every process running on the system. If I'm right there should be a process called "kworker/X:X" where X is some number, and it's consuming way more that it should (like 70% or something like that). This problem will have your CPU running all the time consuming lots of energy. Sadly this problem is not an Ubuntu bug, it's a Linux core bug. I have found a temporary solution for this. Just run
sudo reboot when the kworker process apears, this will reboot your system and (at least in my case) solve the problem until you shutdown or reset your computer
If I'm not right, post the top result anyway, it will help a lot to find out what's your problem.