USAUltium Cells, the joint venture of General Motors and LG Energy Solution, plans to convert its battery cell plant in Spring Hill, Tennessee, to make prismatic LMR cells. Retrofit work is due to begin later in 2026 and to be finished in 2028. According to Ultium Cells, Spring Hill could become the world’s first plant to mass-produce prismatic LMR cells.
What LMR cells are
LMR stands for lithium manganese-rich. The cathode uses a higher share of manganese, which is cheaper than cobalt, the most expensive of the usual cathode metals. GM and LG Energy Solution see the chemistry as a middle ground between low-cost LFP and energy-dense high-nickel cells.
The headline claim is 33% higher energy density than the best LFP cells at a comparable cost, a figure GM first gave in May 2025. Ultium Cells has still not published an energy density in Wh/kg. Electrive lists the open problems as durability, capacity loss and limited fast-charging ability, so the chemistry is not yet mature.
What Spring Hill will build
The plant is to make LMR, LFP and high-nickel cells in both pouch and prismatic formats. The LFP cells made there since June 2026 go to stationary storage systems from LG Energy Solution Vertech, not to vehicles. Investment in the programmes and other site work is expected to reach around 1 billion US dollars by 2030, and the retrofit is expected to create 500 jobs on top of about 1,200 today.
When cars get the cells
GM’s 2025 timeline still stands in the coverage: pre-production at an LG Energy Solution facility by late 2027, commercial production in the United States by 2028. The first targets are electric trucks and full-size SUVs, and GM has said it aims for more than 400 miles (640 km) of range in an electric truck. No model has been named.
The Warren labs behind the cells
GM began researching manganese-rich cells in 2015, prototyping them at its Wallace Battery Cell Innovation Center in Warren, Michigan. The “$900 million” that circulates with this story is a decade-old figure: in May 2026 GM president Mark Reuss wrote that the $2 billion renovation of the Warren technical campus, committed a decade earlier, included nearly $900 million for the Wallace centre and the Ancker-Johnson Battery Cell Development Center. It is not new money for LMR.
