MIT spinoff introduces new liquid metal battery system

From pv magazine USA

Ambri, a Massachusetts Institute of Technology (MIT) spinoff, has developed a liquid metal battery for long-duration energy storage solutions. Designed for daily cycling in harsh environments, the battery has an expected lifetime of 20-plus years with minimal fade, said Ambri. While the battery is now in use in data centers, an announced test with Xcel Energy is the first reported installation by a utility.

Xcel Energy and Ambri plan a year-long test the 300 kWh system at Solar Technology Acceleration Center (SolarTAC) in Aurora, Colorado. SolarTAC is owned and managed by Grey Snow Management Solutions, a tribally owned economic development enterprise. The test center was established in 2009 by original founding member companies Xcel Energy, SunEdison and Abengoa Solar with the mission to test renewable energy technologies in a real-world, grid-connected environments.

Installation of the Xcel system is expected to begin in early 2024, with the system fully operational later in the year. The pilot will test various use cases, including solar and wind integration, capacity management, arbitrage, and ancillary services, among others. It will use the GridNXT Microgrid Platform at SolarTAC to integrate multiple generation sources, such as solar and wind, along with inverters, load banks, and three-phase distribution connections and communications.

Xcel Energy became the first utility in the United States to set a long-term goal of providing its customers zero-carbon electricity. The utility aims to be net-zero across electricity, heating, and transportation by 2050.

“Xcel Energy is a forward-thinking and ambitious utility, and their enthusiasm for testing our system highlights the huge potential for Liquid Metal batteries,” said Adam Briggs, chief commercial officer at Ambri. “Xcel Energy clearly understands the significant value that can be achieved by integrating innovative storage technologies into their renewable portfolio.”

Xcel Energy plans to develop a follow-on memorandum of understanding (MOU) for larger-capacity long-duration energy storage projects to follow the upcoming 300kWh system at SolarTAC.

“Xcel Energy has always been at the forefront among utilities in the transition to carbon-free electricity,” said Justin Tomljanovic, vice president of corporate development at Xcel Energy. “This demonstration project with Ambri allows us to explore a technology that could help us continue to reliably supply the energy our customers depend on throughout the clean energy transition.”

Ambri’s batteries, manufactured in Milford, Massachusetts, feature a liquid calcium alloy anode, a molten salt electrolyte, and a cathode comprised of solid particles of antimony, enabling the use of low-cost materials and a low number of steps in the cell assembly process.

The company said that the active materials in its cells reversibly alloy and de-alloy while charging and discharging. The electrolyte thermodynamically stable with the electrodes, avoiding side reactions such as film-formation that can lead to performance degradation. The negative electrode is fully consumed when discharged, and reformed on every cycle, resulting in what the company said is a “highly repeatable process with no memory effect.”