MEMS Piezoelectric Energy Harvester With Residual Stress Induced Instability

Technology

The technology is a new technique of MEMS-scale energy harvesting, for low-frequency, wide-bandwidth applications. Designed specifically for MEMS applications, the invention lowers the working frequency of the energy harvester device to below 100 Hz in order to match the typical frequency spectrum of ambient vibrations while maintaining the wide-bandwidth and high-power output. The low working frequency increases minute energy harvesting feasibility, while utilizing the natural residual stress present in MEMS thin films.  

Problem Addressed

Microelectromechanical systems (MEMS) energy harvesting from ambient vibrations is a promising solution for increasing the lifetime of autonomous low-power electronic monitoring systems. The usually smaller than a quarter-coin size micro-fabricated mechanical structures driven by ambient vibrations resonates and coverts mechanical energy into usable electrical power through the piezoelectric effect. Current energy harvesting technologies suffer from a small power density and a narrow bandwidth of typical linear resonance-based piezoelectric structures. They also operate at elevated frequencies.  

Advantages

• Lower frequency (<100 Hz) and higher power density (~10mW/mm3)
• Designed specifically for MEMS applications
• Employs residual stress from micro-fabricated thin films to optimize performance
• Low working frequency increases minute energy harvesting feasibility