The SSD storage on these models is soldered onto the logic board, so if the unit is showing no signs of life then you will not be able to access the data that it is holding. Until the unit has powered on we cannot diagnose if the problem could be from a dead battery. It would need to be checked over by an experienced technician to see if there is some shorted circuit or other issue, that is if you didn't have the tools and know how to investigate the issue yourself. Sorry for the bad news.