High-Efficiency Flexible GaAs Solar Modules Used for Unmanned Aerial Vehicles and Stratospheric Airships

High-efficiency flexible solar modules are fabricated with thin-film GaAs solar cells to satisfy the demand for power generation systems of unmanned aerial vehicles (UAVs) and stratospheric airships. The polyimide substrate inverted metamorphic triple junction (IMM 3J) GaAs thin-film solar cells are interconnected using the electrically conductive films by low temperature hot press welding technology, and the solidity of welding and efficiency loss ratio of the cells reach the level of rigid GaAs triple junction solar cells used in space now. Two different size solar cells are integrated and encapsulated separately using the thermo-sensitive adhesive supporting films to achieve a good laminating performance. The 0.2 m2 flexible module consisting of unfilled corner cells has the specific power over 750 W/kg (AM0, 1353 W/m2), and the 0.5 m2 flexible module consisting of rectangle cells has higher specific power over 800 W/kg benefit from a higher cell-to-module ratio (CTM). The two modules have an areal density of less than 500 g/m2. Several near space reliability tests have been done to verify that the flexible solar modules could meet the special environment application need.