SoftBank Awarded NEDO Contract for HAPS Power Systems

Tokyo, Japan - SoftBank Corp said it was selected by Japan's New Energy and Industrial Technology Development Organization for a research contract to develop battery packs and solar cells for High Altitude Platform Stations.

The contract covers fiscal years 2025 through 2028. Testing is scheduled for fiscal year 2028 in the stratosphere.

The project falls under NEDO's Economic Security Important Technology Development Program for ocean monitoring using high-altitude unmanned aircraft.

Three organizations will participate with SoftBank: Enax Corporation, the National Institute of Advanced Industrial Science and Technology, and Choshu Industry Co.

The four conducted a feasibility study in fiscal year 2024 under the same program.

HAPS aircraft use solar cells for daytime power and battery packs for nighttime power while operating in the stratosphere. Battery packs and solar cells account for the majority of an aircraft's weight.

The research will examine lithium metal batteries.

These batteries have higher energy density, measured in watt-hours per kilogram, than lithium-ion secondary batteries.

Solar cell research will address stratospheric light spectrum conditions, low-temperature operation, and weight reduction through the use of thinner materials.

The work focuses on modular technology for environmental resistance and weight reduction.

The fiscal year 2024 study identified technical requirements for HAPS battery and solar cell systems. The new contract is separate but technically related to the prior work.

Short winter daylight hours in high-latitude regions, including Japan and Europe, affect HAPS operations, the company said.