Ultra-small and thin energy-harvesting device based on electromagnetic induction

Abstract

We propose a novel electromagnetic energy-harvesting device (EHD) with a very small and thin structure. The footprint of the device is 20 × 20, the height of the EHD is 7.5 mm, and the volume is 2.4 cm³ . Because the minimum gap between the magnets and iron cores of the coils in the proposed structure can be designed to be very small, a large magnetic flux density differential can be obtained during one power-generation action. This is an advantageous feature of the proposed structure, and the source of the large power generation. According to the experimental results, the proposed EHD generated 102 μW (41.7 μW/cm³ ). Furthermore, the performance of the proposed EHD exceeded the target amount of power generation required to drive recently developed low-power wireless sensors, which can be driven with 100 μW of power.