Elon Musk -- Billionaire Files for Divorce ... Wife Gets MILLIONS!!

Elon Musk is pulling the plug for the second time on his marriage to Talulah Riley -- and she's leaving with a $16 million payday.

The CEO of Tesla Motors and his actress wife originally married in 2010 and split 2 years later. Talulah got a $4.2 million settlement that time.

The couple reconciled in July 2013, but like so many others -- Chris Rock, Slash, Giada de Laurentiis, Jeremy Renner -- Elon apparently wanted a fresh start in 2015 ... since he filed today on New Year's Eve.

A spokeswoman for Musk and Riley said he's agreed to pay her $16 million for this settlement.