MacBook: woke up to an empty battery, how to get battery history?

On Sunday I purchased a brand new MacBook Pro 13" w/TouchBar. I used it a little last night and put it in my backpack with 75% battery life. I shut the lid and assumed the MacBook was sleeping when I put it in my backpack. Unfortunately when I got to school this morning the battery was completely dead. Since I wonder what happened to the 75% battery I had left and am very concerned damage from overheating might happen with it running in a backpack. I checked Console / sys logs and nothing jumps out.

Is there anyway to see the historical battery life to find out if the laptop was left on overnight?

Open activity monitor and select energy. It might take a while to crunch the logs, but that should show you some recent history for 12 hours of activity.

I think it offered more time in the past if you were sleeping, but now it seems to only show you a 12 hour clock window.

The command line tool pmset -g log should dump a much more detailed and verbose log of history going back further than 12 hours. You will probably want to process that - perhaps printing only the lines that match the string Charge and then paging the results.

pmset -g log | grep -w Charge | more
pmset -g log | grep -w Summary- | more

Once you see if it slept and how the charge went down, I wouldn't worry about it running hot while closed. I run Mac at high CPU/GPU while closed clamshell all the time (most of the day) and have never had any issues with longevity in practice or overheating - the CPU throttles down when the blowers or heat can't escape due to a blockage or insulation to stay within safe temperature ranges.