World's first 9 MWh energy storage system by CATL can power a house for 5 years with zero degradation

Contemporary Amperex Technology Limited (CATL), the world's largest EV battery manufacturer with 38% market share, keeps innovating and upgrading its product line.

After announcing the world's first commercialized sodium-ion battery pack for electric vehicles that can travel more than 300 miles on a single charge, it has now launched the first 9 MWh energy storage system (ESS).

CATL's new Tener Stack solution takes advantage of the company's recent breakthroughs in battery chemistry and packaging that allow a significant increase in energy density hence capacity that can fit in a standard 20-foot energy storage container.

About a year ago, CATL unveiled the world's first mass-produced energy storage system with 6.25 MWh capacity, which it called Tener. At the time, it boasted a 20% size reduction and 30% energy density increase compared to previous containerized 20-foot energy storage kits.

Thanks to the use of CATL's solid electrolyte interphase and other innovative technology, oxidation of the highly active lithium in the system's LFP batteries is kept in check, preventing thermal runaway and slowing capacity degradation. This allowed CATL to dole out 5-year zero degradation and 20-year overall warranties with the Tener system for the first time, too.

CATL Tener Stack 9 MWh storage system specs

CATL calls the new energy storage system solution Tener Stack, and it comes with the same zero capacity degradation warranty as its 6.25 MWh predecessor.

"This is the world's first mass-produced 9 MWh ultra-large capacity energy storage system solution," touts CATL, and says that the company "has achieved breakthroughs in system capacity, deployment flexibility, safety and transportation efficiency, marking a new era for large-scale storage technology" with the Tener Stack system.

To put the 9 MWh energy storage capacity in perspective, the 20-foot container is capable of powering the average single family home for up to six years, for five of which CATL guarantees that no capacity degradation will occur in the system's cells. It can charge up to 150 EVs with the current average battery size of electric cars, too. CATL talks about powering the average German family home, though, as the solution was unveiled at the Electrical Energy Storage (EES) 2025 expo in Munich. 

The Tener Stack system is built of LFP battery cells, similar to the ones in popular mobile power stations like Anker's Solix C1000 that is currently 50% off at Amazon. This time around, however, CATL managed to increase space utilization by 45% hence increase the energy density of the system by 50% compared to the conventional 6 MWh ESS solutions.

This will allow utilities to build out a standard grid-level 800 MWh energy storage park with fewer containers and the corresponding decrease in PCS units, requiring 40% smaller land mass to deploy. Not only that, but CATL is addressing the logistical challenges of shipping said containers with heavy LFP battery cells.

It has split the new Tener system in two identical half-height units that weigh a tad under 36 tons each, the typical legal threshold for ground transportation of heavy shipments. Upon arrival, these can be fit together in a 20-foot container, hence the "2-in-1" design and "Tener Stack" system namings.

CATL also optimized the loading process by using standard container spreaders and liners, reducing shipping costs by 35%, while the structural 2-in-1 design allows the Tener Stack system to be transported to remote areas where bridge loads and tunnel heights would otherwise be a challenge.

As for the Tener Stack ESS safety level, CATL cites the class leading thermal management of its LFP batteries and the new gas sensors allowing the system to react to runaway events much faster, while the upgraded insulation increases fire resistance. The system also corresponds to the IEEE693 standard, able to withstand a magnitude 9 earthquake or a Category 5 storm.

The thermal management system is at the top of the container to save on land space and decrease thermal radiation. The resulting noise is now kept to 65 dB at a distance of three feet, making CATL's Tener Stack ESS suitable for urban deployment, too.