Samsung SDI Buys GM’s Stake in Indiana Battery Venture

South Korean battery manufacturer Samsung SDI is ending its battery manufacturing joint venture with General Motors and taking sole ownership of the project's US$3.5 billion plant in New Carlisle, Indiana, citing weaker-than-expected demand for electric vehicles.

Under the agreement, Samsung SDI will acquire GM's 49.99% stake in the entity, known as SynergyCells (or SDI-GM Synergy Cells Holdings), converting the facility into Samsung SDI’s first wholly owned battery plant in North America. Financial terms of the stake purchase were not disclosed.

While dissolving the joint venture structure, the two companies announced a concurrent agreement to jointly develop next-generation prismatic batteries incorporating high-energy-density and fast-charging technologies for potential deployment in future GM electric vehicles.

Strategic Pivot to Energy Storage and Prismatic Tech

Originally announced two years ago in 2024, the Indiana facility was designed to deliver an annual production capacity of 27 gigawatt-hours (GWh), with mass production scheduled to begin in the fall of 2027. Construction at the site had recently slowed, following reports in May that project work had paused amid sluggish EV sales and a broad recalibration of GM's electrification strategy.

Samsung SDI said in a regulatory filing that it will leverage the wholly owned unit to respond to market demand across various applications, including energy storage systems (ESS) alongside electric vehicles. The plant will feature a dedicated production line for ESS batteries.

"The ownership change was made in consideration of market changes since the joint venture was announced, including the slower-than-expected growth of EV demand. The two partners have now decided to seek other forms of cooperation other than the joint venture," Samsung SDI said in an official statement.

The Korean firm added that while its original investment schedule will change following the transition to a wholly owned subsidiary, specific revised capital plans have not yet been finalized and will be disclosed in future regulatory filings.

"This decision reflects shifting market conditions while preserving our strategic partnership with GM. We will continue our joint efforts with GM toward the future of electric vehicles from this plant, while also responding proactively to growing ESS demand in the United States," the company stated.

Broader Electrification Recalibration

The restructuring in Indiana aligns with a broader retreat across the automotive sector as manufacturers adjust output following the loss of a US$7,500 US federal EV tax credit last September. While automakers continue manufacturing electric models, multiple OEMs have lowered factory throughput to align with current demand levels.

For General Motors, the exit from the Indiana joint venture represents the latest adjustment to its EV manufacturing footprint and battery production capacity. The Detroit automaker recorded US$7.6 billion in charges last year related to production cutbacks across its EV and battery operations, including a substantial fourth-quarter write-down.

The move follows a similar transaction last year in which GM sold its stake in an Ultium Cells joint venture facility in Tennessee to its partner, LG Energy Solution, for US$2.14 billion. That joint venture, originally formed in 2020, operates manufacturing facilities in Ohio and Tennessee. In March, GM and LG Energy Solution announced plans to convert the Tennessee plant to produce batteries for energy storage systems.