Harvesting, Storing, and Using Naturally Sourced Energy to Power Communication Transmitters

by Sloan Cinelli

In 1800, Italian physicist Alessandro Volta published results of an experiment he named the Voltaic pile. This stack of zinc and copper is now known as the first electrical battery. Since then, batteries have become increasingly smaller, more powerful, and more efficient. In 1991, the lithium-ion battery was introduced, having the highest energy density and slowest loss of charge in the rechargeable battery market. Today, energy storage and usage rely more heavily on natural energy harvested from their environment. These systems, including solar power, wind energy, or salinity gradients, are becoming more popular due to their renewable nature. However, the power that is generated from using these natural sources fluctuates randomly with time. In the case of solar cells, power attained in one unit could range from 1 μW to 100 mW, a scale 100,000 times different. Hence, charging and discharging these systems are much more variable than in conventional systems.

Bhat et a.l (2017) attempt to fundamentally change the way harvested energy is stored and used in batteries with different efficiencies. Whenever naturally harvested power is lower than the power required for system operation, a system cannot run from that source alone. First, energy must be stored in a battery, then simultaneously drawn from the battery and the natural source, enabling the system to run from the combined power. Continue reading

Extending the Range of Wireless Charging

by Briton Lee

Wireless charging has been quite prominent in recent years, and the implications of the technology is obvious, bypassing the need for any physical connection to power any device with energy. However, the technology is still limited and in its early stages, and the implementation of wireless energy is highly restricted by distance, as it was when it was initially introduced in 2009 with the Palm Pre (Miller 2009). Currently, this technology is seen mostly in wireless charging mats that are only slightly more convenient than plugging in a device. However, during the 2015 Consumer Electronics Show (CES), the company Energous debuted their work on long range wireless charging, WattUp. The technology attempts to achieve the goal of never having to worry about charging devices again. While this extent of wireless charging has been introduced before, there were problems with being able to scale up the efficiency. However, Energous has come a long way since it was established in 2012 as WattUp is able to achieve over 70% efficiency (charging mats are approximately 90% efficient) (Souppouris 2015). Continue reading