ZTT debuts 7.58 MWh liquid-cooled battery storage system

Jiangsu Zhongtian Technology Co., Ltd. (ZTT) has recently unveiled its latest innovation—the ENERGRID NA7 liquid-cooled energy storage system with a storage capacity of 7.58 MWh.

The system presented at the 13th Energy Storage International Conference and Expo (ESIE2025) in Beijing earlier this month, is housed within a standard 20-foot shipping container and is designed for a range of applications including shared energy storage and renewable integration.

The ENERGRID NA7 features a string-based liquid cooling system and incorporates ZTT’s self-developed 3S-integrated PCS. It supports 2000 V high-voltage DC input and AC grid connection, integrating a bidirectional DC/AC inverter that condenses the traditional two-to-three-tier energy conversion process into a single step. This streamlined architecture pushes energy conversion efficiency above 99%.

Compared to its previous generation, the system improves unit-area energy density by 51%, and increases single-container capacity by 51.6%, all without altering the container’s dimensions. Each battery module achieves over 210 kWh of energy per pack, with an IP67 rating that enables safe operation in harsh outdoor conditions.

For thermal management, the ENERGRID NA7 adopts a modular liquid cooling approach, with the battery management system (BMS) working in concert with the cooling infrastructure to keep temperature variations between cells within 2°C. According to ZTT, this tight thermal control extends module lifespan by over 30%. The system’s mechanical structure is reinforced using high-strength steel and corrugated panel technology, resulting in a container with seismic resistance rated at level 9—capable of withstanding extreme conditions such as high altitudes and desert environments during stacking and transport.

Electrically, the NA7 integrates an embedded energy management system (EMS) that supports sub-20 millisecond switching, making it suitable for grid frequency regulation and peak-shaving tasks that require rapid response. Fire protection is structured into a three-tier detection system—at the cabin, cluster, and pack levels—supplemented by both water-based and gas-based extinguishing mechanisms for layered safety assurance.

By utilizing a three-dimensional spatial layout and modular integration techniques, the NA7 reduces the footprint by 40% compared to conventional 5 MWh containers, shortens installation cycles by 60%, and lowers total lifecycle operation and maintenance costs by 25%, according to the manufacturer.

Technical documentation at the exhibition also indicated that the system’s 2000V DC architecture includes reserved interfaces for future expansion to 8MWh, allowing capacity upgrades without altering the hardware structure.

ZTT emphasized that the ENERGRID NA7 is designed to address key pain points in today’s storage market, including low voltage ratings, high conversion losses, and inefficient space utilization.

The system has entered the industrial validation phase and is being positioned for wide adoption across renewable energy storage, grid-side peak shaving, and commercial and industrial applications. As a fully self-developed solution, spanning battery cell materials, system integration, and intelligent control, NA7 reflects ZTT’s growing end-to-end capabilities in the storage equipment sector.