Ambri’s product is a ready-to-install DC containerized system, complete with shelves of cells, thermal management, weatherproof outer enclosure, and a battery management system (BMS), for applications that require high energy capacity, frequent cycling, long life and high efficiency.
Cells are assembled onto trays and connected within a thermal enclosure to form a MWh-scale system, which is separately then coupled to the grid using standard industrial DC-AC bi-directional inverters. The system is insulated and “self-heating” when operated, requiring no external heating/cooling to keep the batteries at operating temperature. Multiple systems placed together on site are connected in parallel, enabling unlimited upward scalability for large-scale projects.
Capacity: 1000 kWh, 250 kW
DC Efficiency: exceeds 80% under wide range of use cases
Response time: <500 milliseconds
Voltage: 550 —1150 V
Footprint: 10-foot shipping container
Each Ambri cell is comprised of a robust stainless-steel housing, a positively polarized case, and a negative terminal protruding from the center of the lid.
During transportation, cells are shipped at ambient temperature and are inactive; they have zero cell voltage and are unable to pass current, offering significant safety advantages during assembly and transportation.
Once delivered on-site, heaters within the system bring the cells up to their operating temperature, which activates them and allows them to start storing or returning electrical energy.
Although the system is expected to remain at operating temperature continuously for the life of the system, cells are designed to undergo dozens of thermal cycles, from room temperature to 500 °C, without impacting cell performance.
Cells are also highly tolerant of over-charging or over-discharging, and are not subject to thermal runaway, electrolyte decomposition, or electrolyte off-gassing, each of which could lead to significant safety events with other cell chemistries,
The Ambri battery platform
The liquid metal battery is comprised of 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 active materials in Ambri’s cells reversibly alloy and de-alloy while charging and discharging. The electrolyte is thermodynamically stable with the electrodes, avoiding unwanted side reactions such as film-formation that can degrade the performance of other cell chemistries. Furthermore, the negative electrode is fully consumed when discharged, and then is reformed on every cycle, resulting in a highly repeatable process with no memory effect.
With these unique operating characteristics, Ambri’s liquid metal battery technology avoids common degradation mechanisms that cause capacity fade in other chemistries.
At room temperature, Ambri’s cell is non-conductive and its active materials are solid metals and a solid electrolyte. Upon heating to 500˚C temperature, Ambri-based battery systems operate at maximum performance level no matter the external temperature and require no power-hungry air conditioning.
Ambri-based systems generate their own heat during use, thereby eliminating the need for auxiliary power for temperature control. These systems like to be used – a full charge/discharge cycle at least every two days will keep the system at its operating temperature and higher duty cycles will not increase degradation.
Ambri’s commercial systems will be packaged in 550 – 1150 VDC containers with up to 1 MWh of capacity. These containers will be factory assembled and shipped to site fully populated and sealed. Each of these containers will contain no replaceable or serviceable components. This eliminates on-site maintenance and means that the container becomes the modular and replaceable system component. For projects with 10 or more containers connected in parallel at the DC side of site PCS, system reliability is enhanced through N+1 redundancy at the container level.
Lowest cost energy storage system
Ambri cells utilize commonly available electrode materials that cost 1/3 of those in NMC lithium-ion cells. The manufacturing of Ambri cells is far simpler and requires 1/3 to 1/2 the capital expense per MWh of production than lithium-ion. Furthermore, Ambri-based systems do not have cooling, fire suppression or module- and rack-based BMS equipment as lithium ion-systems require. For these reasons, long-duration Ambri-based battery systems are a fraction of the cost of lithium-ion when comparing 20-year, eight-hour-duration systems.
Lithium-ion batteries are projected to drop in price from current levels to less than $100/kWh at some time in the mid to late 2020s. Even compared to this low future lithium-ion price of $100/kWh, these energy storage systems will be significantly more expensive than Ambri-based battery systems.
No risk of combustion
Ambri energy storage systems will answer the world-wide need for grid storage with an efficient and safe system. As lithium-ion batteries have flooded the market for grid storage, opportunities for safer, longer life batteries for long-duration applications have emerged.
To date over 20 lithium-ion energy storage systems have resulted in explosions or fires. Ambri batteries are not explosive, combustive or temperature sensitive. No level of overcharging, over-discharging, short circuiting or temperature has caused any safety concerns with these cells.
Ambri has engaged with Underwriters Laboratories to develop an appropriate set of safety tests for the certification of Ambri cells. Ambri’s cells have demonstrated passing of these tests with ease.