SK Innovation plans to invest five-point-one trillion won to build electric vehicle(EV) battery plants in the U.S. through a joint venture with the U.S.’ second largest automaker, Ford Motor Company. 

The battery maker said Tuesday that its board of directors approved the investment earlier on Monday for the plan which will be carried out by the joint venture BlueOvalSK from next month to December 2027.

It is SK Innovation’s single largest investment. 

Initially, the firm was set to inject three trillion won into the plants’ construction but decided to raise its amount after the volume of EVs that would carry the batteries doubled from what was initially expected.

Ford and SK Innovation plan to invest some 13 trillion won, or eleven-point-four billion dollars, to build an electric F-150 assembly plant and battery complex, along with two additional battery plants. 

BlueOvalSK will invest ten-point-two trillion won into the three plants, with one in Tennessee and two in Kentucky. According to SK Innovation, the plants will be the largest of their kind to be built in the U.S.