SEOUL (Reuters) -South Korea's Samsung SDI said on Wednesday it has completed an agreement with General Motors to build a joint electric vehicle (EV) battery factory in the U.S. state of Indiana.

The two companies will invest approximately $3.5 billion to build a new battery cell manufacturing plant with an annual production capacity of 27 gigawatt hours (GWh) initially, Samsung SDI said in a statement.

The South Korean battery maker said the joint plant aims for mass production in 2027 and annual capacity is expected to rise to 36 GWh under expansion plans.

($1 = 1,326.0000 won)

(Reporting by Heekyong Yang and Joyce Lee in Seoul, David Shepardson in Washington; Editing by Chris Reese)