ACC passes five million battery cells in France as Stellantis prepares to pause two plants over a long-range battery shortage

Automotive Cells Company says it has produced its five-millionth lithium-ion cell at its gigafactory in Billy-Berclau/Douvrin in northern France. The milestone was put on show at the 2026 Paris Motor Show on the French automotive industry association's stand. ACC says cells and modules already in the field are enough for nearly 40,000 vehicles.

The figure is a running total since the plant started up. It lands in the same fortnight that Stellantis will pause two French plants because it still cannot get enough of ACC's long-range batteries for the models customers want most.

Who ACC is and what it builds

ACC is a European cell and module maker founded in 2020. Its shareholders are Stellantis, Mercedes-Benz and Saft, the TotalEnergies battery subsidiary. It develops NMC lithium-ion products and employs about 2,500 people in France: research and a pilot plant in Nouvelle-Aquitaine, and the gigafactory in Hauts-de-France.

Its cells and modules now go into eight Stellantis long-range electric models: the Peugeot E-3008 and E-5008, Jeep Compass, Lancia Gamma, DS N°7 and N°8, Citroën C5 Aircross and Opel Grandland. ACC says the first production block at Douvrin is running a 5×8 shift pattern seven days a week, that scrap rates are moving towards internal targets, and that September module output was close to the company's entire 2025 module production.

Allan Swan, chief executive since May 2026, called five million cells "an important milestone" and "a clear demonstration of the progress achieved by our teams", in ACC's English-language release. He also said Europe needs rules that let battery makers compete on equal terms. The release itself called for the EU's proposed Industrial Accelerator Act to be brought in quickly to support demand for European-made batteries.

The stoppages Stellantis has already booked

On 29 September Stellantis said it would pause Sochaux from 23 to 30 October and Rennes from 22 to 30 October. Electrive, citing Reuters and a company statement, reported that those two stops are tied to shortages of ACC batteries for long-range electric models. Mulhouse's longer pause from 15 to 30 October has other causes and should not be rolled into the same story.

Stellantis also gave a second reason. It said it wants to avoid building up inventory of other vehicles that does not match demand, because demand is concentrated on the long-range electric versions that buyers wait longest for. A Stellantis spokesperson told Reuters, according to electrive: "Unfortunately we are not yet receiving enough of the batteries, despite big progress in ACC's production."

Sochaux builds models including the Peugeot 3008 and 5008. Rennes builds models including the Citroën C5 Aircross. Those lines sit on the same STLA Medium family that uses ACC batteries for the high-range variants.

Why a five-million mark and a plant pause can both be true

Making cells and shipping finished modules are separate steps. A cell only leaves the line once it has passed formation and testing, and modules then need their own assembly and release checks. Running the first block every day of the week adds hours. It does not by itself guarantee that enough approved modules reach Sochaux and Rennes for the long-range versions buyers are ordering.

Bloomberg reported in February, citing internal sources, that early in the year ACC was equipping only about 1,000 cars a month with long-range batteries, well below plan, and that Chinese specialists had been brought in to cut scrap. Matthieu Hubert, ACC's secretary-general, told Bloomberg then that the ramp-up was proving difficult. Automobilwoche reported in April that some dealers had long-range deliveries pushed into the first or second quarter of 2027. Those reports are older than this week's milestone; they explain why Stellantis still talks about a shortfall even as ACC publishes stronger September numbers.

ACC says it is supplying Stellantis in line with the production plans the two agreed. Stellantis says it would build more long-range cars if it had the batteries. Neither company has published the figures that would settle the difference.

What comes next at Douvrin

ACC's next capacity step is a second production block at Billy-Berclau/Douvrin, rated at 12.9 GWh, due to start operating in 2027 for Mercedes-Benz electric vehicles. Electrive puts the site at just under 26 GWh once that block is in, with a longer-term picture of three blocks and about 40 GWh. After dropping separate gigafactory plans in Germany and Italy, ACC is concentrating further investment on the French site.

Five million cells have now been made at Douvrin, and September module output was close to all of 2025. Rennes and Sochaux still stop later this month. The Mercedes block will add capacity from 2027 and will do nothing for October.

Sources: Automotive Cells Company, "ACC unveils its 5 millionth 'Made in France' cell for electric vehicle batteries at the 2026 Paris Motor Show alongside the PFA", 12 October 2026; electrive, "ACC announces five million battery cells 'Made in France'", 12 October 2026; electrive, "Battery shortage: Stellantis pauses EV production in France", 30 September 2026 (citing Reuters and Stellantis); Industrial News, "ACC reaches five million cells at French battery factory", 13 October 2026; Bloomberg, February 2026, and Automobilwoche, April 2026, both via electrive, 30 September 2026; ACC English release via AFP/MediaConnect, 12 October 2026.