What’s new in solar energy harvesting for sensors?

At Sensors Expo 2018, Ben LeNail, Director of Business Development at Alta Devices, a maker of thin, flexible solar photovoltaic cells for energy harvesting, provided an update on the company’s technology, its applications and energy harvesting solutions for sensors. The company’s specialty photovoltaic cells are ultra-high efficiency devices. Alta Devices has held the world record for solar cell efficiency for five years.

Today, the company makes two products. The single junction, gallium arsenide (GaAs) has a conversion efficiency of almost 30% (28.9%). Their dual-junction product is almost 32%. The dual junction products are mainly sold for use in fixed wing drones to provide greater autonomy and longer flight time. However, the company is also starting to make inroads into automotive applications to put solar material on cars as well as putting solar strips on sensors and other Internet of Things (IoT) products that operate in low light and need more autonomy.

At the show, he displayed several energy harvesting solutions. The first was a solar-powered Bluetooth sensor that used a 2 cm x 5 cm solar cell to produce 220 mW of power. This level of power was also used for a solar-powered sensor tag. The power can be stored in a battery or supercapacitor. Another display showed a 2 cm x 2.5 cm solar cell that produced 110 mW for powering a fitness tracker.

The company’s Gen4 provides a 30% reduction in mass resulting in an areal (surface) density of 170 g/m² for unencapsulated devices. Their goal is to provide customers with the best power-to-weight and power-to-area combination available on the market.