Supercapacitor Options for Energy-Harvesting Systems

Low-power microcontrollers have done much to improve longevity in energy-harvesting systems. Clever architectures and use of low-power modes lets micros draw nanoamperes of current while preserving registers and configuration data. This allows designers to use smaller and less dense energy storage solutions that were not feasible in the past.

Nevertheless, energy storage, which plays a key role in ambient-energy-harvesting systems, is still needed in most cases as a power buffer to store enough energy to provide the power bursts needed to acquire and transmit data during peak demand, particularly if data is going to be transmitted across a wireless network. These energy storage devices generally take the form of either a battery or a supercapacitor (supercap).
Supercaps, which bridge the gap between conventional capacitors and rechargeable batteries, offer performance characteristics that are well suited for energy-harvesting environments. Supercaps can provide capacitance values up to 10,000 times that of conventional electrolytic capacitors. Moreover, while in the past supercaps could only provide about 10 percent of the energy storage density of chemical batteries, new supercap chemistries and architectures are yielding higher-density energy sources that can be charged relatively quickly.
 
For more detail: Supercapacitor Options for Energy-Harvesting Systems