Amprius Unveils 500 Wh/kg SiCore 500 Battery Cell for Long-Endurance Drones and HAPS

Amprius Introduces SiCore®500 – High Energy Density Cells for Unmanned Aviation

FREMONT, Calif.–(BUSINESS WIRE)– Amprius Technologies (“Amprius” or the “Company”) (NYSE: AMPX), a leader in silicon anode lithium-ion batteries, today announced a new 500 Wh/kg SiCore^® cell, designed for long-endurance aviation. The cell delivers 500 Wh/kg at a 1C continuous discharge rate and can be produced on conventional lithium-ion battery manufacturing equipment.

Reaching 500 Wh/kg has typically required specialized materials handling and non-standard cell construction. Second-generation SiCore is designed to reach the 500 Wh/kg mark on standard equipment, processes, and cell formats already installed across Amprius’ global contract manufacturing network. That is intended to give customers a path from qualification to volume with no specialized tooling and to give Amprius a way to extend its highest-performing tier without departing from its asset-light manufacturing model.

Amprius has reached and exceeded 500 Wh/kg before, but those cells relied on specialized processes and were never produced at commercial volume. Second-generation SiCore is the first Amprius platform designed to reach the same energy on conventional manufacturing infrastructure.

The new SiCore cell is optimized for the sustained, low-rate discharge profiles required for High-Altitude Platform Stations (HAPS), fixed-wing drones, and other long-endurance applications. In HAPS, stored energy and battery weight decide whether persistent stratospheric flight is possible: fixed-wing platforms bank daytime energy to fly overnight, while lighter-than-air platforms draw on it for propulsion and station keeping. Higher specific energy can add flight time, range, and payload without adding weight.

Amprius has supplied cells for AALTO HAPS since 2018 across multiple generations of the Zephyr platform, including a 2025 flight that has reported setting a 67-day world endurance record. AALTO, an Airbus subsidiary, is developing 100% solar-electric HAPS for connectivity and earth observation applications.

Pierre-Antoine Aubourg, COO at AALTO HAPS, said:

Energy density is fundamental to Zephyr’s endurance,

“Our longstanding relationship with Amprius has focused on advancing the energy storage required for persistent stratospheric flight. Continued gains in specific energy can meaningfully extend flight duration and expand mission capability.”

Amprius designed the second-generation SiCore platform to close the gap between demonstrated energy density and what customers can order at volume.

Dr. Ionel Stefan, CTO of Amprius Technologies, said:

Reaching 500 Wh/kg is a significant technical milestone, but how we reached it matters as much as the number,

“By achieving that performance level on conventional manufacturing equipment, our aviation customers can qualify this cell knowing that we have designed a cost-effective, scalable path to volume behind it.”

Amprius currently expects commercial availability in Q4 2026, with cells built in customer-specific formats and in the standard small uncrewed aircraft systems (sUAS) pouch format defined by SAE JA1016. Initial production is planned at the Company’s Fremont, California facility, with volume production expected to scale through existing global contract manufacturing partners.

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