The UAW said it had filed a petition with the National Labor Relations Board on behalf of approximately 900 workers at Ultium Cells after a majority of workers had signed cards authorizing the union to represent them.

"By refusing to recognize their majority will, Ultium - which is a joint venture between General Motors and LG Energy Solution - has decided to ignore democracy and delay the recognition process," UAW President Ray Curry said in a statement.

(Reporting by David Shepardson; Editing by Mark Porter)