High-efficiency thin-film triple-junction PV panel from Sharp being tested in space
As noted by Tech-On!, the Japan Aerospace Exploration Agency (JAXA; Tokyo, Japan) has revealed that it mounted thin-film triple-junction solar panels on the "Kounotori No. 6," an unmanned Japanese spacecraft launched on December 9, 2016 from Tanegashima Space Center to ship supplies to the International Space Station (ISS). The position where the photovoltaic (PV) panels were installed is used as a platform for verification tests. The verification test of the solar panels will be carried out in orbit and will last until reentering the aerosphere.
The solar panel, which was developed by Sharp (Osaka, Japan), combines three kinds of solar cells made from III-V semiconductor materials that each use a different spectral region for PV conversion. The conversion efficiency of the solar panel is about 32%, which JAXA claims is the world's highest efficiency for a practical space-based solar panel. The previous efficiency record was 29.5%.
In May 2016, Sharp announced that it had achieved a module conversion efficiency of 31.17% with triple-junction compound solar cells in a nonconcentrating configuration. The individual size of the new solar cell is about 27 cm2, and its weight is as low as 0.33 g. The weight reduction was realized by using a plastic film as a substrate.
Sharp's previous space solar cell uses a glass substrate and weighs 2.2 g. The film substrate is not only lightweight but also flexible and can be attached to the main body of a satellite. The system for the verification test is equipped with instruments for measuring current, voltage, and temperature of the solar panels.
JAXA is examining whether the panels can withstand the forces of launch as well as cosmic and ultraviolet rays in space.
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John Wallace | Senior Technical Editor (1998-2022)
John Wallace was with Laser Focus World for nearly 25 years, retiring in late June 2022. He obtained a bachelor's degree in mechanical engineering and physics at Rutgers University and a master's in optical engineering at the University of Rochester. Before becoming an editor, John worked as an engineer at RCA, Exxon, Eastman Kodak, and GCA Corporation.