"Giga Berlin… will build batteries, powertrains and vehicles, starting with Model Y," he tweeted.
His electric vehicle and energy company, Tesla, built its Gigafactory 3 in Shanghai this year.
The company unveiled its first Model 3 vehicles made in China this month.
Musk told an awards ceremony in Germany the "Gigafactory 4" would be built near the new Berlin airport, Reuters reported.
Former Tesla employee and now Benchmark Mineral Intelligence's principal consultant Vivas Kumar recently told Mining Journal he believed battery raw material producers would need to significantly ramp up their capacities within the next five years - otherwise car companies would need to drastically reduce their EV plans.
There is a current over-supply of lithium but a panel at LME Week in October agreed the battery mineral had a bright future, while others are concerned about a critical shortage of nickel to drive the EV revolution.