European carmakers have spent four years waiting for CATL's second European plant to make a cell. On 22 September 2026 it finally did. The Chinese battery maker said trial production has started on the first two lines at its Debrecen site in eastern Hungary, the plant that is meant to become its largest manufacturing base anywhere outside China.
Trial production is not series production. CATL describes the run as commissioning, optimising and validating the line equipment and processes — the stage where a factory proves it can build a cell repeatably before it builds them for sale. The company has not said when series output begins.
What actually changed
The milestone is narrower than the headline capacity figure suggests, and worth separating out. The 100 GWh number applies "once all facilities are ready", on CATL's own wording. The first phase is 34 GWh, and only two lines are running.
What did change is the regulatory position. CATL received an occupancy permit in August 2026 and says it has now completed every pre-condition attached to its integrated pollution prevention and control permit, with on-site inspections signed off by the Hajdú-Bihar County Government Office. That matters because Debrecen has spent most of 2026 unable to proceed.
In August, Hungary's new government withdrew the exemption that let strategic investments bypass environmental and planning rules, and CATL's site was restricted to equipment debugging. Before that, work in three areas of the cell building was suspended after nine employees showed elevated nickel levels; the county office fined the company about €31,000. Hungarian authorities have since confirmed the identified deficiencies were resolved.
The plant in numbers
| Item | Figure |
|---|---|
| Trial production start | 22 September 2026 |
| Lines running | First two |
| First-phase capacity | 34 GWh |
| Planned full capacity | 100 GWh |
| Announced | August 2022 |
| Cell building construction | From summer 2023 |
| Equipment installed | Spring 2026 |
| Occupancy permit | August 2026 |
| Modules built since autumn 2024 | 537,000 |
The module line is the part often missed: Debrecen has been assembling battery modules since autumn 2024 and has produced 537,000 of them. Cells were the missing step.
Why a Tesla owner should care
CATL is one of Tesla's two largest cell suppliers. Model Y production at Grünheide has drawn on CATL lithium-iron-phosphate cells alongside NMC cells from LG Energy Solution, and CATL already runs a German plant in Thuringia ramping toward an initial 14 GWh. A 100 GWh site inside the EU changes the arithmetic on both tariffs and shipping distance for every carmaker buying CATL cells for European assembly — Tesla included.
It also lands while Tesla is building its own European cell capacity. The company committed $250 million in May 2026 to take 4680 output at Grünheide from 8 GWh to 18 GWh, with cell production there expected from 2027. Even at 18 GWh, Tesla's own German line would be a fraction of what Debrecen is designed to produce.
CATL named no customers. Its statement refers only to "leading European automakers", and no carmaker has confirmed it will take Debrecen cells. Until series production starts and a customer is named, the plant remains a capacity promise rather than a supply line.