Samsung SDI is acquiring General Motors’ 49.99% stake in the joint battery plant venture in New Carlisle, Indiana, according to a regulatory filing, becoming the sole owner of the $3.5 billion facility. The value of the deal was not disclosed.
The agreement makes the plant Samsung SDI’s first wholly owned facility in North America, while GM will retain a supply relationship and a separate agreement with the South Korean company to develop next-generation prismatic batteries for potential use in future electric vehicles.
A Joint Venture That Lasted About Two Years
The two companies first announced their partnership in April 2023, then completed the establishment of the joint venture in 2024 under the name SDI-GM Synergy Cells Holdings. The plan was to build the plant on 680 acres to produce nickel-rich NCA prismatic cells under Samsung SDI’s PRiMX brand.
The plant was targeting the start of mass production in 2027, with an initial annual capacity of 27 gigawatt-hours and the possibility of increasing it to 36 gigawatt-hours, in addition to providing more than 1,600 jobs. The project was part of a wave of battery plant announcements in the United States, built on expectations that electric vehicle sales would continue rising throughout the decade.
Slowing Demand Reshapes Investment
Samsung SDI directly linked the ownership change to market developments, saying the decision came in light of changes that had occurred since the joint venture was announced, including slower-than-expected growth in electric vehicle demand.
According to the article, U.S. automakers reduced electric vehicle production after the $7,500 federal tax credit expired on September 30, 2025, affecting the battery supply chain. GM had recorded a charge of approximately $6 billion as it scaled back electric vehicle production plans, while its other battery project with LG Energy Solution also experienced a temporary production halt and the furloughing of workers as manufacturing plans changed.
Samsung SDI’s shares fell by about 4.5% after the announcement, signaling investor concern that the plant’s risks had shifted entirely to the company.
Energy Storage Battery Production Line
Samsung SDI plans to add a production line for energy storage system (ESS) batteries to the plant. This comes as the company expands its focus in the United States from electric vehicle cells to stationary storage, amid rising demand related to power grids and data centers.
The article argues that full ownership of the plant gives Samsung SDI greater flexibility to direct its production capacity toward the type of demand that actually materializes. For GM, selling the stake represents a reduction in the risks of owning a battery facility, while retaining the supply and joint development agreements instead of fully withdrawing from the relationship.
Electrek’s Opinion presents the deal as GM stepping back from owning battery manufacturing amid weak short-term U.S. demand, while Samsung SDI is betting on the possibility of converting part of the facility to energy storage battery production.