Workers at electric vehicle battery maker Ultium Cells’ Warren, Ohio facility voted to unionize on Friday, joining the United Auto Workers labor union.

The effort overwhelmingly won by a vote of 710 to 16, with one void, according to a Dec. 9 press release.

Ultium Cells is a joint venture between GM and LG Energy Solution. The two companies invested $2.3 billion in the joint venture’s first battery cell facility in Warren, which began production in August. 

However, discussions regarding Ultium workers' right to organize at both the Ohio and Tennessee facilities – the latter of which is still under construction – began in May of last year.

In October, the International Union, UAW filed a petition for election with the Cleveland office of the National Labor Relations Board on behalf of approximately 900 Ultium workers in Warren.  

UAW President Ray Curry said in an Oct. 31 press release that a majority of workers had signed cards authorizing the labor union, but that Ultium refused to recognize the effort, pushing the group to hold an NLRB vote. 

“By refusing to recognize their majority will, Ultium ... has decided to ignore democracy and delay the recognition process,” Curry said in October. “Make no mistake: whether it is by card check or union election, these workers will be members of the UAW.”

Ultium said in a statement Friday it had received the National Labor Relations Board election results and respects the Ohio workforce’s decision.

“We look forward to a positive working relationship with the UAW,” Ultium said in a statement.

Curry said in a Dec. 9 statement that the vote shows Ultium workers in Ohio want to maintain UAW’s high standards and wages the organization has built into the auto industry.