High efficiency flexible triple junction solar panels

Abstract

The Marines have increasing battery needs as fighting technology puts higher demands on the power they use. In an effort to offset this demand, the marines are investigating alternative energy sources, one being solar power. Mobile photovoltaics (PV) are a technology that can address these needs by leveraging flexible high efficiency III-V photovoltaic technology. The development of a lightweight, high efficiency solar panel to mount on, or stow in, a backpack and used to recharge a warfighters' battery was demonstrated. The panel consists of a 10 × 3 solar array of 20 cm2 epitaxial lift-off (ELO) Inverted Metamorphic (IMM) triple junction solar cells. In the first two phases of the project, single-junction GaAs cells with an efficiency of ~ 21% under AM1.5 illumination were used. Several of these systems were outfitted during Limited Objective Experiments (LOE) in February 2012 and August 2012. In the third and most current phase of this project, panels of triple-junction cells with an expected efficiency of 28-30% under AM1.5 illumination. Data from these LOEs are presented here. Although the panels are expensive, they have been demonstrated as a viable technology.