What is Energy Harvesting?

Energy harvesting is a technology that collects tiny amounts of energy such as heat, vibration, light, and electromagnetic waves around us and converts them into electricity. The idea is to effectively utilize tiny amounts of energy that are usually wasted.

The development of this technology has a long history. For example, the principle of thermoelectric conversion, the Seebeck Effect, was discovered in 1821, nearly 200 years ago. Then, in the 1950s, the United States and the former Soviet Union paid attention to the application of this technology in the space and military fields and began to actively engage in research. The discussion of practical application began around 2000, and the rapid improvement of the conversion efficiency of power generation elements became a driving factor.

The biggest selling point of energy harvesting technology is that it can save the trouble of replacing batteries, wiring and maintenance. For example, the "battery-free switch" that Mitsumi Electric began to supply samples in the fall of 2010 controls lighting wirelessly. Specifically, it uses the principle of electromagnetic induction to convert the force of pressing the button into electricity, uses this electricity to activate the wireless chip, and then sends a signal.

In addition to switches, wireless sensor networks also have a high affinity with energy harvesting. In order to put the trace amount of electricity obtained to good use, in addition to increasing the power generation of components, the low power consumption of peripheral components is becoming increasingly important. If the performance of wireless transceiver ICs, MCUs, and sensors is further improved, the possibility of energy harvesting technology "blooming" will increase rapidly.

Efficient use of trace electricity

Although European and American companies have taken the lead in practical application, Japanese companies are also beginning to unveil related products. For example, Mitsumi Electric began shipping samples of battery-free switches in the fall of 2010 (a). When used in wireless sensors, a power generation of about 100μW is required (b).