Google maps shuts down by itself
If the device is unusually slow, or other apps get closed too, I would expect it's a memory shortage problem.

Some other service/app/proces (possibly part of the system), unrelated to Maps, uses so much main memory that that there is not enough memory available at the time you run Maps, and the system needs to kill an app to free memory, and decides to kill Maps.  

It this is the case, the problem would be somewhere else, and Maps in itself could run fine.