MacBook Pro Mid 2014 freezing and shutting down

My Mac has been completely fine until last night when it began randomly shutting off. I’ll be using it as normal browsing safari and after about a minute it will freeze for a few seconds, then go black, completely turning off. When I power it back up it starts from a normal power up.

I’ve noticed if I power it on, log in and don’t do anything, it doesn’t shut down. I’ve tried SMC reset and that didn’t make a difference but booting in safe mode appeared to fix the problem as long as I stay in that mode.

Does anyone have any experience with this kind of issue and have any idea what could be causing it?

MacBook Pro 15 inch retina mid 2014

2.5ghz intel core i7

16gb RAM

500gb SSD
Battery Condition: Replace Soon