Oregon-based energy storage provider ESS Tech has announced its new Bridge battery energy storage system (BESS), which consists of modular 1.2 MWh building blocks with sodium-ion battery cells, designed to deliver power to data centers, critical infrastructure operators and other commercial customers.
The new system marks ESS’s first foray into sodium-ion batteries. Prior to the introduction of Bridge, the company had exclusively offered iron flow batteries that use liquid electrolytes composed of iron, salt, and water, designed primarily for long-duration energy storage (LDES) applications ranging from eight to 22 hours.
The new sodium-ion platform, however, uses sodium-ion battery cells sourced from Alsym Energy to deliver high-density power for short- to medium-duration needs. In its release statement, the company said the Bridge BESS is “capable of a wide range of charge and discharge profiles, from 1 to 16 hours or more depending on configuration.”
ESS says the addition of sodium-ion chemistries to its offerings was driven by market demand for energy storage that can react to different use cases than its LDES iron flow products. The company says it has seen nearly $1 billion in demand for sodium-ion technology since first announcing its partnership with Alsym in April.
“Bridge is how we meet the demand we’re already seeing,” said ESS CEO Drew Buckley in a statement. “AI workloads are reshaping what data centers need from energy storage, and sodium-ion handles those power needs more effectively than conventional technologies.”
ESS describes the Bridge modules as “plug-and-play” units, with all system hardware components included inside a 10-foot container. The company says the units are stackable and can deliver 4.8 MWh of storage in the same footprint as a traditional 20-foot battery container. In addition to the hardware ESS provides complete system integration and energy management software.
The company says its sodium-ion systems are engineered to operate in temperatures ranging from -40 C to 50 C (-40 F to 122 F), and adds that the batteries use air cooling rather than more complex liquid cooling or HVAC systems, and are designed to eliminate risk of fire from thermal runaway.
Additionally, ESS claims the technology relies on an alternative supply chain that offers reduced exposure to risk from critical mineral constraints and geopolitical sourcing concerns.
In general, sodium ion batteries show much lower incidence of thermal runaway compared to traditional lithium-ion batteries. Recently, a team of researchers in China developed a novel sodium-ion battery chemistry that uses phase change materials to polymerize the battery electrolyte in case of exposure to high temperatures, effectively creating a “self-protecting” battery that instantly halts the chain reaction that can lead to thermal runaway.
