Both plants will start production in 2026, employ thousands of people and supply batteries to European car makers.
With Taiwan a focal point in tensions between Washington and Beijing, the company also wanted to secure a base overseas.
Volkswagen was expected to announce a battery plant location in Europe late last year but said in March it is awaiting more clarity from Europe on subsidies before making a decision.
The plant by Taiwan's ProLogium would be its first overseas car battery factory.
A second plant could also be constructed in parallel elsewhere, a Northvolt spokesperson said, including in North America.