High efficiency solar cells in Piccard project: SOLAR IMPULSE subjected to gruelling tests at the Jungfraujoch

The solar cells intended for application in Bertrand Piccard's solar-powered airplane SOLAR IMPULSE currently under construction have passed their first climate and altitude tests at 3,500 metres at the Jungfraujoch (Switzerland), demonstrating high levels of efficiency above 22 per cent. BKW FMB Energy Ltd (BKW) and its subsidiary company Mont-Soleil (GMS) have been carrying out these tests since December last year. Drawing on their many years of experience in photovoltaic technology, BKW and GMS solar specialists have over the last three years performed a range of development tasks for Bernard Piccard's SOLAR IMPULSE project.  Based on the knowledge gained since 1992 at the International Test Centre in Mont-Soleil (in the Bernese Jura), since the end of 2008 BKW and GMS have been testing the solar cells intended for the solar-powered aircraft under extremely harsh climate conditions using special measuring equipment - and this at an altitude of 3,580 metres, nearly one-half of the solar aircraft's maximum flight altitude.

Efficiency level is some 50 per cent higher than that of conventional solar cells

During testing at the Jungfraujoch extreme fluctuations in temperature were experienced together with strong gales of some 250 km/h. The first test results show that the efficiency level under various temperature and radiation conditions is greater than 22 per cent, i.e. some 50 per cent higher than with conventional solar cells, BKW emphasizes in a press release. They also show that the ultra-thin monocrystalline silicon high-performance cells used are highly efficient. BKW has already carried out studies into high-altitude cirrus clouds (2005/2006) on behalf of the SOLAR IMPULSE project, as well as studying the flow of energy between solar cells and batteries (2006/2007).
Source