CATL’s Biggest Plant Outside China Just Started Making Battery Cells

CATL began trial production at its Debrecen plant in Hungary on September 22, marking the point where four years of construction and permitting finally turns into working cell lines. The site is planned for 100 GWh of annual capacity once fully built, which would make it CATL’s largest manufacturing base anywhere outside China.

What Trial Production Actually Means Here

CATL announced the Debrecen project in August 2022, started building the first cell manufacturing building in summer 2023, and had it fitted with production equipment by spring 2026. The company secured its occupancy permit in August and cleared the remaining requirements under its Integrated Pollution Prevention and Control permit before trial operations could begin.

The plant is currently in trial production mode, the stage where CATL sets up, tunes and validates the manufacturing equipment and processes before switching to series production, and only the first two of the plant’s lines are running for now. Those two lines cover the initial 34 GWh phase of the planned 100 GWh site, and CATL hasn’t given a date for when full scale output starts. The company has actually been making something at Debrecen for a while already: battery modules have come off a separate line there since autumn 2024, with 537,000 built so far.

The Safety Suspension That Slowed Things Down

Getting here wasn’t smooth. Earlier this year, Hungary’s County Government Office temporarily suspended operations in parts of the plant over occupational safety concerns tied to nickel exposure, affecting nine employees. CATL says it carried out health and safety fixes afterward, and Hungarian authorities have since confirmed the issues were resolved, clearing the way for the current trial phase.

That episode came against a wider backdrop of political friction, after a change of government in Hungary added uncertainty around how Chinese manufacturers operating there would be treated. CATL says it will keep monitoring environmental, health and safety indicators through the trial period and report the results to regulators as it goes.

Why Debrecen Matters for Europe’s Car Industry

Once it reaches full capacity, Debrecen becomes a central supplier for automakers building EVs in Hungary and across the wider region, letting CATL sit closer to the car plants it supplies instead of shipping cells in from China. It’s one piece of a broader European strategy: CATL has been expanding into logistics too, signing a memorandum of understanding with DHL on green freight corridors, and pushing newer chemistry like sodium ion cells through a European partnership with Alfen.

The company already holds the largest share of the world’s EV battery market by a wide margin, and a fully running Debrecen plant would extend that lead into Europe’s own supply chain instead of leaving European automakers dependent on cells shipped in from China. The real test comes once CATL moves past validating its equipment and starts pushing Debrecen toward the output the site was actually built for.

FAQ

When did CATL start trial production at its Debrecen plant? CATL began trial production on September 22, 2026, running the first two of the plant’s cell manufacturing lines.

How big will CATL’s Debrecen plant be? The site is planned for 100 GWh of annual capacity once fully built, which would make it CATL’s largest manufacturing base outside China. The current trial phase covers an initial 34 GWh.

Why was CATL’s Debrecen plant delayed? Hungarian authorities temporarily suspended operations in parts of the plant earlier this year over occupational safety concerns related to nickel exposure, affecting nine employees. CATL says it resolved the issues before trial production began.

Has CATL made anything at Debrecen before this? Yes. The site has been producing battery modules on a separate line since autumn 2024, with 537,000 built to date, ahead of the new cell manufacturing lines starting trial production.

When will CATL’s Debrecen plant reach full production? CATL hasn’t given a timeline for full scale series production. Trial production is used to set up and validate the equipment and manufacturing process first.

Which automakers will CATL’s Debrecen plant supply? CATL has said the plant is meant to serve major automakers building electric vehicles in Hungary and the wider European market, strengthening the region’s EV supply chain instead of leaving it reliant on cells shipped from China.

Featured Image: CATL