Workers at a Ford Motor Co. joint-venture battery plant in Kentucky have formally asked the federal government to hold a vote on joining the United Auto Workers, the union said.

The United Auto Workers union is petitioning the National Labor Relations Board to hold an election at a Kentucky battery plant run by a Ford Motor joint venture, the union said in a release Wednesday.

The United Automobile Workers union asked a federal labor regulator to conduct an election at a factory Ford jointly owns with a South Korean battery company.

The Kentucky autoworkers, who want to join the United Auto Workers, filed for a union election Tuesday, a key development in the union’s campaign to organize Southern auto-factories and EV battery facilities.

The BlueOval SK plant, owned by a partnership of South Korea's SK On and Ford, is the latest battery battleground for the union.

Workers at a Kentucky BlueOval SK Battery Park filed for an election to join the United Auto Workers union Tuesday, marking the new year’s first major union election petition filed in the South —and one that could foretell future union activity in Tennessee.