CATL and Seres Group have agreed to add 10–12 GWh of annual battery capacity at Seres' manufacturing hub in Chongqing, lifting total output at the site beyond 20 GWh. The expansion is the core commitment in a new long-term strategic cooperation agreement the Chinese battery maker and the Chongqing-based automaker announced this week.

The deal extends a partnership with a measurable track record. Since Seres launched its Aito brand, developed with Huawei, every Aito model has shipped with CATL cells. Cumulative deliveries of CATL-equipped Aito vehicles now exceed 1.2 million units, CATL confirmed.

The timing matters for both companies. Tier 1 battery suppliers face slowing growth in China's domestic EV market, and CATL is pushing to lock in volumes with anchor customers while exporting capacity overseas. For Seres, secured cell supply underpins its own export push into Europe, the Middle East and Central Asia.

What is the 'Plant in Plant' model?

The Chongqing facility operates on a 'Plant in Plant' basis: CATL builds and runs dedicated battery production lines inside Seres' vehicle assembly complex, rather than shipping cells from a separate plant. The model shortens the supply chain between cell manufacture and vehicle assembly, and it ties capacity decisions directly to one customer's order book.

The new agreement accelerates Phase 2 of that project. The confirmed plan adds 10–12 GWh per year, taking total capacity at the site above 20 GWh. CATL stated the figure in its announcement; no completion date or investment sum has been disclosed. To put the scale in perspective, 20 GWh is roughly enough cells for 300,000 to 400,000 long-range electric vehicles per year, depending on pack size.

The companies framed the agreement around three workstreams:

• Capacity expansion — the Phase 2 build-out at Chongqing, from roughly 10 GWh today to more than 20 GWh.
• Charging and service ecosystem — joint expansion of supercharging networks and battery services into a full-lifecycle offering for vehicle owners.
• Overseas market development — coordinated entry into Europe, the Middle East and Central Asia, which the companies said would bring "high-quality products and services" to global customers.

Confirmed plans versus stated intentions

Only the capacity figure comes with a number attached. The supercharging and export pillars read as statements of intent, without disclosed targets, timelines or financial commitments. That distinction matters when weighing the announcement: the Phase 2 expansion rests on a concrete capacity plan from the operator, while the overseas ambitions remain directional.

Seres' export case also depends on factors outside this agreement. Europe's tariffs on Chinese-built EVs and pending battery sourcing rules will shape how much Aito volume CATL cells can support in that market. Neither company addressed those constraints in the announcement.

What to watch next

Three markers will show whether the agreement converts into output. First, a groundbreaking or equipment order date for Phase 2 at Chongqing would set the clock on the 20 GWh target. Second, CATL's utilization rates at the site, reported in its quarterly results, will indicate whether existing lines run near capacity or carry headroom. Third, any European market entry by Aito with CATL-sourced packs would test the export pillar against tariff policy.

For now, the hardest number stands at 1.2 million cumulative CATL-equipped Aito deliveries, and the next capacity milestone is the crossing of 20 GWh at Chongqing.