DETROIT, Aug 28 (Reuters) - The United Auto Workers

(UAW) said on Wednesday it won a vote at a Ford

joint-venture plant in Kentucky to unionize it, but believed 41

challenge ballots still pending to be illegitimate.

A win for the union would give it a much-needed boost in the

U.S. South by securing membership at another electric vehicle

(EV) production facility, a key battleground as the automobile

industry electrifies.

The union urged the company to recognize that a majority of

BlueOval SK's production and maintenance employees had chosen to

join it.

"They (Ford) should immediately drop their anti-democratic

effort to undermine the outcome of the election," the union,

which represents workers across Ford, General Motors and

Jeep-maker Stellantis, said in a statement.

Referring to the challenge ballots, it added, "We believe

they are illegitimate and represent nothing more than an

employer tactic to flood the unit and undermine the outcome."

The National Labor Relations Board and Ford did not respond

to a request for comment outside regular business hours.

The BlueOval SK joint-venture expects to bring on 5,000

workers across two Kentucky battery plants when they are at full

capacity, a spokesperson said.

The first, which now employs about 1,450 people, started

production this summer, while the second has been delayed.

UAW President Shawn Fain has sought, with little success, to

expand on a historic win last year at a Volkswagen plant in

Tennessee. The labor group suffered a defeat at a Mercedes plant

in Alabama in May 2024.

Fain has emphasized the importance of winning votes at

battery and EV plants, a focus of its 2023 strike against

Detroit's automakers.

The Kentucky plant produces batteries for Ford's EVs,

including its F-150 Lightning electric pickup.

The union previously notched victories with Ultium Cells, a

joint venture between GM and LG Energy Solution, at battery

plants in Ohio and Tennessee.