Samsung SDI has acquired General Motors’ 49.99% stake in their SynergyCells battery joint venture, giving the battery manufacturer full ownership of a New Carlisle, Indiana, plant originally planned as a major piece of GM’s expanding U.S. electric vehicle battery supply chain.

The ownership change comes more than three years after GM and Samsung SDI first announced plans to jointly build the battery facility, and it illustrates how quickly EV manufacturing strategies have shifted as automakers and suppliers adjust to changing demand.

Samsung SDI said slower-than-expected EV demand factored into the companies’ decision to move away from the joint-venture structure. Once construction is completed, Samsung SDI plans to initially use the facility to manufacture batteries for the growing U.S. energy storage system, or ESS, market.

The companies are not ending their battery relationship. Samsung SDI and GM have also signed a new joint development agreement covering next-generation prismatic battery cells for potential future EV applications. The companies said the cells will target high energy density and fast-charging capability.

Samsung SDI said future prismatic cells developed with GM could potentially be manufactured at the Indiana facility.

From EV Expansion to Energy Storage

The current plan looks significantly different from the one GM and Samsung SDI outlined when the partnership was first announced.

Charged Fleet reported in April 2023 that the companies planned to invest more than $3 billion in the battery cell plant, which was originally expected to begin operations in 2026. At the time, the companies projected more than 30 GWh of annual capacity and planned to jointly operate the facility.

GM Chair and CEO Mary Barra said at the time that batteries produced through the partnership would help the automaker scale EV capacity in North America to well beyond 1 million vehicles annually. The facility was also expected to broaden the battery formats available to GM, with plans at the time calling for nickel-rich prismatic and cylindrical cells.

By the time Samsung SDI and GM finalized the joint-venture agreement in August 2024, the companies put the investment at approximately $3.5 billion and identified New Carlisle as the location. The facility was expected to create more than 1,600 jobs and begin with 27 GWh of annual production capacity, with expansion plans that could take it to 36 GWh. Mass production had also shifted from the original 2026 target to 2027.

At that point, the plant was still being positioned squarely around EVs. Samsung SDI said it would produce nickel-rich prismatic batteries expected to be used in upcoming GM electric vehicles.

Two years later, Samsung SDI will instead become the plant’s sole owner and initially direct its output toward stationary energy storage.

Battery Makers Look for More Flexibility

GlobalData sees the transaction as part of a larger adjustment taking place as battery manufacturers balance EV investments with growing opportunities in energy storage.

“From Samsung SDI’s viewpoint, acquiring full ownership provides more control over capacity, scheduling, product mix, and investment decisions,” said Madhuchhanda Palit, senior automotive analyst at GlobalData. “With ESS demand growing more robustly than EV battery demand in the US, the Indiana plant can be oriented toward prismatic cells for ESS in the near term, allowing Samsung SDI to pivot more responsively.”

Full ownership also gives Samsung SDI its first independently operated battery production facility in North America. For GM, meanwhile, selling its ownership position reduces the automaker’s direct exposure to the manufacturing operation while preserving access to Samsung SDI battery development.

“For GM, the exit suggests a recalibration of its EV strategy, reducing its exposure to cell production risk amid EV demand softness,” Palit said. “By signing a joint development agreement for next-generation prismatic cells, GM retains access to advanced battery technology without bearing full capacity investment or operating risks.”

The change does not mean the Indiana factory is permanently leaving the EV supply chain. Samsung SDI said the facility could eventually manufacture the prismatic cells being jointly developed with GM.

But compared with the companies’ 2023 announcement, the priorities have clearly shifted. What began as a jointly owned plant designed to add EV battery capacity for GM will now open under Samsung SDI ownership with energy storage as its first target market.

“Samsung SDI’s acquisition reflects evolving market realities: ESS demand is strengthening, EV volume forecasts are moderating, and incentives favor domestic control and flexibility,” Palit said. “For GM, it reallocates risk and capital while maintaining technological collaboration.”