SK On has secured a major U.S. energy storage system (ESS) battery supply contract with NeoVolta Power, agreeing to deliver 9 gigawatt-hours of lithium iron phosphate (LFP) battery cells from 2027 through 2031. The deal, estimated at about 1.5 trillion won, or roughly $1.09 billion, will be produced at SK On’s Georgia plant, with NeoVolta Power assembling the cells into finished packs for sale. The companies are also discussing an additional 9 GWh under a subcontracting model in which NeoVolta assembles SK On cells into ESS packs that SK On then repurchases; if finalized, total cooperation would reach 18 GWh. SK On is converting U.S. electric-vehicle battery lines for ESS use because surging North American demand exceeds what in-house pack assembly alone can supply, and industry observers see the structure as a way to raise factory utilization. The volume is far larger than last year’s Flatiron ESS contract, which confirmed only 1 GWh plus a 6.2 GWh priority negotiation right, against SK On’s U.S. base of 100 GWh in joint capacity and 22 GWh in standalone facilities. Parent SK Innovation shares rose 6.24% to 124,200 won after the announcement, also supported by higher oil prices, a lithium-price rebound and ESS expansion expectations.