Ambri, based in Cambridge, Massachusetts, is an early-stage company working to develop and commercialize liquid metal battery (LMB) technology. The company’s goal is to produce a low-cost and long-lifespan storage technology that will fundamentally change the way electric power systems are operated worldwide. Ambri’s LMB technology was invented at the Massachusetts Institute of Technology (MIT) in the lab of Professor Donald Sadoway and was inspired by the concept of reversing large-scale electrometallurgical processes that consume huge quantities of electricity (for example: aluminum smelting.)
The LMB cell technology is unique in that it is the only battery where all three active components (anode, cathode and electrolyte) are in the liquid state when the battery operates. The design is robust – these active components of the cell are housed within a stamped stainless steel container. Each sealed crucible contains three liquid layers– the negative and positive metal electrodes and a molten salt electrolyte separating them. The system operates at elevated temperatures (~460 °C), and these three layers self-segregate when heated, floating on top of each other based on density differences and contiguous immiscibility. Within the simple cell design, there aren’t any moving parts or membranes. Unlike other battery technologies made of solid state components where the electrodes degrade over time due for example to particle cracking or dendrite formation, LMB electrodes do not, enabling the expected lifespan of the battery to exceed 15 years.
Grid-scale LMB consists of individual cells stacked into packs, which are the smallest replaceable unit of the battery. Packs are configured into Ambri Cores (200 kWh), which are approximately 1 meter cubed. Each Ambri system provides 2 MWh (1 MW of peak capacity) and contains 10 Cores.
LMB technology has a number of distinct advantages for grid-scale energy storage. The long lifespan of the battery is crucial. Ambri has demonstrated cells running in the laboratory for more than 2,000 cycles with a 0.0002% capacity fade per cycle. This implies that after 10,000 cycles (at 2 cycles a day, this would be 14 years) the battery will retain over 98% of its original capacity. Second, Ambri’s LMB is unique in its ability to economically serve as both an energy and a power resource for the electric grid. These systems can charge/discharge energy for multiple hours to reduce capacity constraints on the grid, while simultaneously -- responding in tens of milliseconds to grid signals -- switching from charging to discharging and the reverse nearly instantaneously, to serve as a frequency regulation or voltage support resource.Third, Ambri’s battery is safe. The LMB has a number of safety features inherent in its design, which provides great confidence in its ability to operate without incident for decades. For example, the active components of each Ambri cell are housed in a one-eighth inch thick steel container, which is welded shut. Ambri’s cells are not electrically active until they are heated to their operating temperature of 460 °C. When systems are cold – e.g., during shipping or during maintenance – cells do not have any active voltage and cannot accept or deliver electrical current.
Ambri has contracted to deploy five prototype battery systems in 2015 with customers in New York, Massachusetts, Alaska, and Hawaii. These include installations in small power grids and on military bases. Notably, Ambri has been awarded a contract by NYSERDA to test a prototype system at the NY-BEST Commercialization Center in Rochester next year. Afterwards, the system will be moved to Con Edison’s service territory in New York City and tested on its distribution system.In addition, Ambri has been awarded a contract alongside Raytheon to deploy a 1 MWh system to Joint Base Pearl Harbor – Hickam in Hawaii in 2016 through a contract with Naval Facilities (NAVFAC). Ambrihas established a manufacturing facility in Marlborough, Massachusetts and will be expanding its capabilities to be able to deliver commercial systems in late 2016 and 2017.
According to Kristin Brief, Vice President of Corporate Development at Ambri: “Ambri is pleased to be working with NY-BEST. They’ve been a great partner and have helped us to engage stakeholders in New York. We are looking forward to deploying one of our first prototype systems to the NY-BEST Commercialization Center in Rochester next year. This will be a big milestone for Ambri’s commercialization efforts, and a key first step in bringing Ambri’s Liquid Metal Battery technology to New York State.”
The original research at MIT that led to the founding of Ambri was funded by grants from the Department of Energy’s ARPA-E program, Total and other sources. Ambri’s current investors include Khosla Ventures, Bill Gates, Total, KLP Enterprises and the Swiss insurance company, GVB. To date, Ambri has raised more than $50 million in equity financing and is well positioned to commercialize this unique energy storage technology.