Ultium Cells to make LMR prismatic EV cells at Spring Hill, Tennessee

Ultium Cells LLC, the battery cell joint venture of General Motors and LG Energy Solution, said it will upgrade its Spring Hill, Tennessee plant to produce lithium manganese rich (LMR) prismatic battery cells for future GM electric vehicles. The release, which the Ultium Cells newsroom dates September 28, 2026 and of which GM's newsroom posted its own account on September 29, says facility modifications will begin before the end of 2026 and are expected to be completed in 2028, that the expansion is projected to create 500 new jobs on top of a current workforce of 1,200, and that the combined investment in the LMR program, the plant's existing LFP storage-cell program and facility improvements will reach $1B by 2030.

Ultium Cells says the Spring Hill facility "is expected to be the first in the world to mass produce prismatic LMR battery cells" and describes LMR as a technology "with the potential to deliver 33% higher energy density than lithium iron phosphate (LFP)," which it calls today's leading affordable battery chemistry, "but at a comparable cost." The release gives no cell specification behind the 33%: no watt-hours per kilogram or per liter, and no statement of whether the comparison is by weight or by volume.

GM's own September 29 post restates the 500 jobs, the 1,200 employees and the 2028 completion, says the technology "is designed to offer energy density 33% greater than" LFP, and words the first claim as "the first manufacturer globally to commercially produce this next-generation technology." It omits the $1B figure and the storage-cell program. Kurt Kelty, GM vice president of battery and sustainability, is quoted in the Ultium Cells release calling the establishment of LMR prismatic cell production at Spring Hill "a key step in GM's strategy to match the right battery technology to customer needs"; GM's post runs the same passage, with "GM's" changed to "our", as unattributed narration.

What May 2025 already said

GM and LG Energy Solution announced on May 13, 2025 that they would commercialize LMR prismatic cells for future GM electric trucks and full-size SUVs, that Ultium Cells planned to start commercial production of the cells in the United States by 2028, and that pre-production was expected to begin at an LG Energy Solution facility by late 2027. That release said the two companies' engineers "have developed" a cell that "unlocks 33% higher energy density compared to the best-performing lithium iron phosphate (LFP) based cells" at a comparable cost; GM's same-day explainer by Kushal Narayanaswamy, its director of advanced battery cell engineering, puts the same figure as an estimate ("GM estimates that our new LMR cells will get 33% more energy density at a comparable cost than LFP"), and the September 2026 release says "potential to deliver." The May release also said GM aims to offer more than 400 miles of range in an electric truck.

What is new in September 2026 is the site, the construction window, the headcount and the dollar figure. What has shifted is the framing: the May 2025 release named trucks and full-size SUVs, while the September 2026 release says "future GM electric vehicles" and names no vehicle, and neither it nor GM's post repeats the late-2027 pre-production step at an LG Energy Solution facility.

The explainer also lays out the chemistry. GM's EV trucks and SUVs used NMCA (nickel manganese cobalt aluminum oxide) cells as of May 2025, he wrote; a typical high-nickel cell is roughly 85% nickel, 10% manganese and 5% cobalt, while GM's LMR composition is around 35% nickel, 65% manganese and "virtually no cobalt." He wrote that LMR had historically been hampered by technical barriers, in particular short battery life and voltage decay, and that GM's new LMR cells, with proprietary dopants and coatings, particle engineering and process changes, "can match the lifespan of current generation high-nickel cells."

Spring Hill's product plans since July 2025 and the storage market

Spring Hill has had three product plans announced since July 2025. On July 14, 2025, GM announced that Ultium Cells would convert cell lines at Spring Hill to produce low-cost LFP cells, under a headline calling them EV battery cells, "building on a $2.3 billion investment announced in 2021," with conversion beginning later in 2025 and commercial production expected by late 2027. That release said the facility "currently employs about 1,300 people."

On March 17, 2026, Ultium Cells said Spring Hill would begin producing LFP cells for energy storage systems, delivered to LG Energy Solution Vertech, the US energy storage division of LG Energy Solution, enabled by a $70M investment in process retooling to be completed by Q2 2026. That release said the 700 employees furloughed in January 2026 were in the process of returning, that NCMA GEN1 cell production had been consolidated to Warren, and quoted Bob Lee, president of LG Energy Solution North America, saying LG Energy Solution's North American storage manufacturing footprint "has helped offset slower than expected EV demand."

On July 7, 2026, Ultium Cells said production of LG Energy Solution's JF2 LFP cells for storage systems had begun, that the conversion of some existing capacity took less than five months, and that all Spring Hill team members had returned. The September 2026 release dates the start of that production to June 2026, counts 1,200 employees against the "about 1,300" GM cited in July 2025, and the only LFP program it names is the storage-cell production for LG Energy Solution Vertech customers; the July 2025 plan for LFP EV cells by late 2027 goes unmentioned, and the release carries no 2027 date. Injae Pahk, President of Ultium Cells, says in the September 2026 release that it "marks Ultium Cells' second major investment in Spring Hill"; the March 2026 release quoted him calling the LFP retool "Ultium Cells' first major retooling of the Spring Hill process equipment."

Other deals The Duck Curve has covered point at that market: SK On's 9 GWh LFP pouch-cell supply deal with NeoVolta Power, announced August 31, 2026, will supply US-made LFP cells for NeoVolta Power's storage products from 2027 through 2031, and LG Energy Solution's partnership with B2U Storage Solutions, announced in a release datelined Seoul, September 22, 2026 and posted September 24, explores the same US market with repurposed LG Energy Solution batteries.

Outlook

If the modifications finish in 2028 as Ultium Cells expects, production would land at the back end of the "by 2028" window GM gave in May 2025, and the vehicles named then were electric trucks and full-size SUVs; the September release names none, so which model gets the first LMR pack is open. The $1B-by-2030 figure covers the LMR program, the LFP storage program and facility improvements together, which implies spending continuing past the 2028 completion date; the release does not split it. Given the reason Bob Lee gave in March 2026 for the storage line, LMR volume will depend on GM's EV sales when the lines come up, and EIA said on September 30, 2026 that new EV sales in the first half of 2026 were down 19% compared with the second half of 2025, without sourcing the figure; the release gives no cell capacity in GWh for either program.