Application of Solar Cells on a High Altitude Stratosphere Balloon

The use of solar cells can effectively reduce the stratosphere balloon load and increase its theoretical flight time. To guide the application of solar cells on the stratosphere balloon, a calculation model was developed. A configuration analysis model with the consideration of HIT solar cell parameters and the lithium-ion battery parameters was developed. It was based on the solar radiation model and the working model of the PV energy system. The influences of the balloon geometry, size and operation parameters, such as operation latitude, seasons, flight direction, and speed, etc. were analyzed. It can be used to analyze the energy balance of the balloon. A simulation was conducted to a specified balloon. The result indicated that the general design of the PV energy system could be easily determined with this calculation model.In order to study the practical performance of solar cells on the stratosphere balloon and verify the calculation model, a stratosphere balloon was designed to carry out a solar cell flight test experiment at an altitude of 20 km. The test used a 1-square-meter HIT solar module. In response to this, a dedicated circuit was designed to collect real-time battery voltage and current data, and access to the solar cell I-V curve. At the same time, the solar cell operating temperature and its corresponding solar radiation data was measured. According to this, the working efficiency of the solar cell on the stratosphere balloon was obtained, and the working performance data of the solar cell that varies with the flight of the stratosphere balloon was summarized. The experiment confirmed that the theoretical calculation model of solar cell performance was consistent with the measured results. This test provides practical data that support for the application of solar cells to stratosphere balloons.