Samsung SDI is ending its existing battery cells joint venture project with General Motors in Indiana — and acquiring the US auto giant’s stake in the plant under construction in New Carlisle.

However, the South Korean battery firm said on August 11 it had signed a new agreement with GM to jointly develop a next-generation prismatic battery cell for potential future EV applications.

The move allows Samsung to establish its first independently operated battery production base in North America, which will now have an initial focus on producing ESS batteries.

The new deal comes just two months after Samsung and GM announced their $3.5 billion Indiana partnership was on “pause”. Samsung has now agreed to acquire GM’s 49.99% stake in the SynergyCells joint venture set up by the two.

Samsung said the arrangement was made in consideration of market changes since the joint venture was announced — including slower-than-expected growth of EV demand.

Construction of the battery plant is already underway. The facility will initially be used to produce ESS batteries with the potential to include prismatic cells jointly developed with GM.

A Samsung spokesperson said: “While reflecting recent market changes, this acquisition decision is to continue the strategic partnership with GM. We will continue our commitment to an electrified future with the partner, while utilising the plant to proactively respond to the fast-growing ESS market in the US.”

When the joint venture project was announced in 2024, the partners said they would invest around $3.5 billion to build the plant, which would have an annual production capacity of 27GWh initially, targeting mass production in 2027. The annual capacity was expected to rise to 36GWh.