Samsung SDI acquired GM's 49.99% stake in SynergyCells on August 11, converting the New Carlisle, Indiana plant into a wholly owned facility intended for ESS batteries (press release). Purchase price undisclosed.
The building exterior is complete but cell-manufacturing lines were never installed; construction paused in May 2026. Site development cost estimated at ~$300M by TechTimes (trade reporting, not company-confirmed). The original 27 GWh NCA prismatic plan for GM's EV program described equipment that was never ordered and should not be carried into ESS capacity projections.
Sole ownership eliminates the JV consent structure that governed chemistry, format, and end-market decisions. Samsung can now orient the facility toward ESS unilaterally. It also absorbs the full utilization risk on a plant with no disclosed ESS capacity target, chemistry selection, SOP date, or committed offtaker. A new co-development agreement with GM preserves a technology relationship but specifies no purchase volumes.
Separately, StarPlus Energy (Stellantis JV, Kokomo) has ~7 GWh NCA ESS output and LFP lines targeting October 2026 cell production (ETNews trade reporting; Samsung SDI Q2 call). New Carlisle contributes no incremental supply on any near-term horizon.
Legal close: Reuters described the acquisition prospectively — agreement signed, closing not yet confirmed as of Aug 14.
Key unknowns (Aug 14): purchase price, ESS GWh target, cell chemistry (NCA vs. LFP), whether prismatic format carries over to ESS use, SOP, named ESS customers, retooling cost.
Original plan, now void: 27 GWh expandable to 36 GWh, NCA prismatic, $3.5B total investment, SOP 2027 (Samsung SDI, Aug 2024).
Indiana incentives: Whether the state development agreement survives the ownership and use-case change is unresolved. Underlying agreement not located in public filings.
Enchem dependency: Electrolyte supplier planning to serve SynergyCells sought additional time after the May pause. Post-buyout status undisclosed.
JV dissolution pattern: Third major US EV battery JV restructured in under a year — Ford/SK On (BlueOval SK, Dec 2025), GM/LG Energy (Michigan Ultium, May 2025), now GM/Samsung SDI.
45X: Sole ownership simplifies claimant designation under IRS Form 7207 but does not constitute a production credit claim. Filing status not public.