Amprius Technologies, Inc., a leader in next-generation lithium-ion batteries with its Silicon Anode Platform, today announced it has signed purchase orders from AALTO HAPS (“AALTO”) for the Company's 450 Wh/kg ultra-high-energy density SiMaxxTM cells.

Amprius' 450 Wh/kg SiMaxx cells are designed to operate in some of the most extreme flight conditions while maximizing flight range and payload capacity. These attributes make SiMaxx cells the only known commercially available batteries capable of supplying enough endurance for persistent HAPS (High-Altitude Platform Stations) overnight stratospheric flight operations in all seasons or at higher latitudes. This is a key consideration for AALTO, with Zephyr the only fixed-wing HAPS to have demonstrated day and night longevity in the stratosphere.

“Amprius is at the forefront of enabling electric flight with our high-energy density cells designed to improve aircraft range while reducing weight,” said Dr. Kang Sun, CEO of Amprius Technologies. “AALTO is one of Amprius' long-standing customers, and we look forward to continuing to support its world record high-altitude pseudo satellite missions with our high-energy density cells.”

The collaborative efforts between AALTO and Amprius reached a milestone in 2022 with a record-breaking 64-day cross-continental test flight of a Zephyr 8/S, a monumental achievement for both companies. During the event, Amprius' 400 Wh/kg high-energy cells powered the flight without descending from the stratosphere, allowing AALTO to break its own previous record of more than 25 days.

Pierre-Antoine Aubourg, Chief Technical Officer at AALTO, said: “Zephyr relies on the most cutting-edge sustainable technology and design to push the boundaries of solar-powered, stratospheric flight. In Amprius, AALTO has a highly valued partner that continues to produce ultra-high-energy density batteries that are critical to our success, enabling improvements in nighttime operations as well as the extent of coverage latitude. It is a partnership that will remain highly strategic for both companies over the coming years.”

Amprius' SiMaxx cells are equipped to operate in challenging environments and are, therefore, ideally suited for aviation and military applications. Amprius began fulfilling shipments against the new AALTO purchase orders in Q1 of 2024 and expects to continue fulfilling shipments in the coming months as the Company advances its efforts to increase its SiMaxx production capacity in Fremont, CA.