500 Wh/kg Silicon Lithium-Ion Cells for Stratospheric Platforms

Amprius and AeroVironment propose to develop a long-duration solar-electric stratospheric platform that helps all military assets, from individual soldier to command centers, to acquire and communicate information by creating battlespace networking, communication, and observation nodes. As a replacement for satellites, these platforms are inexpensive to launch and operate and can be positioned for months-long persistent service or moved on demand. Funding this project to develop a high energy density battery solution from a TRL 3 to 6 would enable global coverage of the platform. The main enabling technology for stratospheric flight is a high energy density battery solution, which is needed to power the aircraft overnight, and rechargeable from solar power during the day. Developed over the last 10 years, AmpriusÆ silicon nanowire anode technology enables and enhances all applications where batteries are used, extending operation time of soldier batteries, extending flight time for drones, including perpetual flight for solar-electric drones. The pure silicon anode cells double energy density compared to state-of-the-art commercial batteries. A 500 Wh/kg energy density level is needed for persistent (overnight) stratospheric flight at all latitudes and in most of the seasons, even when the duration of the night is longer than 12h. Amprius proposes to develop and apply its anode and cell technology into a battery product for the AeroVironment stratospheric platform, integrating it and demonstrating it in operational conditions in 18 months. Amprius is a Li-ion cell manufacturer with silicon nanowire anode technology that enables an increase in energy density of 50-100%Ācompared to cells containing graphite anodes. AmpriusÆ main technology, a highly engineered silicon structure made of 100% silicon nanowire, has recently been demonstrated in cells ofĀ500 Wh/kg and energy densities of over 1300 Wh/L. The technology thus provides a significant step forward in lithium-ion battery development, roughly equivalent to the entire improvement over the last two decades with graphite anodes.