General Motors will close Brownstown Battery Assembly, the Michigan plant that builds the high-voltage battery packs for the Cadillac Celestiq, when its lease runs out next summer. Automotive News first reported the plan, and GM confirmed it on October 20, 2026, in a statement given to both Car and Driver and InsideEVs. A GM spokesperson said the lease ends next year and that the company "is planning to transition this work to other nearby GM facilities."
What the plant does
Brownstown is a leased, 480,000-square-foot building in the Detroit area that opened in 2009. Its recent work was small but specialized: battery packs for the hand-built Celestiq sedan, plus batteries and electric drive units for the Chevrolet Corvette E-Ray hybrid. Part of the building also served the hydrogen fuel-cell venture GM ran with Honda, a program that has since ended.
Very few people still work there. According to InsideEVs and GM Authority, the plant employed around 300 people at its peak and was down to fewer than a dozen after GM cut its electric-vehicle output. GM told affected workers earlier this year and has offered them jobs at other plants in the area.
What happens to the Celestiq
GM has not said where Celestiq packs will be assembled once Brownstown closes. Car and Driver reports that the company declined to name the new site, and that the Celestiq remains in production for the 2027 model year. The Corvette side matters less going forward: Car and Driver notes that the E-Ray has effectively been replaced by the new Corvette Grand Sport X.
The Celestiq is Cadillac's flagship, a custom-commissioned electric sedan that is built by hand, priced from roughly $340,000 at launch and, according to Cadillac's Celestiq page, sold by inquiry only through a network of certified Celestiq dealers in extremely limited numbers.
Part of a wider pullback
The closure fits a pattern. GM handed its planned Lansing, Michigan, battery plant to LG Energy Solution in 2024, and InsideEVs notes it left a battery joint venture with Samsung SDI in Indiana earlier this year. GM also dropped its fuel-cell plans with Honda and with Piston Automotive, and it has taken over the lease on the 300,000-square-foot Detroit building meant for the Piston project while it decides what to do with it. The backdrop is a weaker EV market: InsideEVs reports GM sold 25,472 EVs in the US in the third quarter of 2026, compared with 66,501 a year earlier.
Owner and buyer brief
What it means for owners and buyers
- Current owners: Nothing changes today. GM's statement describes the battery work as moving, not ending, and warranty coverage is a GM obligation rather than something tied to one building. Nothing in the announcement alters it.
- Owners waiting on a battery repair: Celestiq service runs through the certified Celestiq dealer network. If your car needs battery work in 2027, ask the dealer how parts supply will be handled during the move and what lead time to expect.
- Buyers commissioning a car: Because pack assembly will change locations during 2027, ask your dealer or design concierge to confirm your build slot and delivery estimate in writing, and to tell you if the transition affects either.
- Corvette E-Ray owners: The same applies to E-Ray batteries and drive units, which also came from Brownstown and are moving with the rest of the work, per GM.
Dashbird tipIf a warning light comes on in any Cadillac EV, plug in Dashbird to read the stored trouble codes in plain English before you call the dealer, so you can describe the problem precisely.
