ESS Tech has announced the launch of Bridge, a modular sodium-ion battery energy storage system designed for grid operators, AI data centers, critical infrastructure, and commercial and industrial customers, offering an alternative to conventional lithium-ion battery solutions.

The Bridge system uses a standard module unit of 1.2 megawatt-hours, featuring a plug-and-play design that allows for installation using heavy-duty forklifts and operation with simple air cooling. The modules are stackable and scalable, enabling deployment of up to 4.8 MWh of storage capacity within the footprint of a standard 20-foot container, supporting charge and discharge configurations from 1 to 16 hours or even longer durations.

Regarding safety, the Bridge design eliminates the fire risk associated with thermal runaway in lithium-ion batteries. It does not require complex HVAC or liquid cooling systems, thereby reducing operational complexity and total lifecycle costs. The system is designed to operate reliably across a wide temperature range from -40 to +50 degrees Celsius and has a design service life of 20 years.

In terms of materials, Bridge is based on sodium-ion technology, utilizing widely available and abundant materials. This approach avoids the dependency on critical minerals and geopolitical supply chains associated with lithium-ion batteries, while also helping customers reduce their exposure to risks related to foreign entities of concern.

ESS CEO Drew Buckley stated that AI workloads are transforming the energy storage requirements for data centers, and sodium-ion technology can meet these power demands more effectively than traditional technologies. Since the company entered the sodium-ion field, it has accumulated nearly $1 billion in early-stage customer opportunities.

ESS had previously focused on long-duration energy storage using all-iron flow battery technology. The launch of this sodium-ion product line marks the company's entry into the short- and medium-duration energy storage markets. The company formed a strategic partnership with Alsym Energy in April of this year to secure a supply of sodium-ion battery cells and modules.