The new investment in the Ultium Cells Spring Hill plant will boost battery output from an annual capacity of 35 gigawatt-hours to 50 GWh, when the plant is operational in late 2023. It is one of at least four U.S. joint venture battery plants planned to supply GM electric vehicles as the largest U.S. automaker ramps up EV production.

The new investment follows $2.3 billion announced in April 2021 and will add another 400 jobs. The factory will employ 1,700 workers when fully operational.

The first Ultium joint venture plant in Warren, Ohio began production in August. Workers next week at the $2.3 billion Ohio plant will vote whether to unionize after the United Auto Workers (UAW) petitioned to represent about 900 workers.

(Reporting by David Shepardson; Editing by Cynthia Osterman)