Piezoelectric Energy Harvester with Eccentric Mass
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Solution Overview
Problem
Existing energy harvesters are inefficient in transferring mechanical energy from human motion to piezoelectric materials due to random and low-frequency motion, limiting their power output for powering wearable, portable, and healthcare devices.
Innovation Solution
The design incorporates a piezoelectric diaphragm and an eccentric mass with a piezoelectric stress inducer, which converts rotational motion into mechanical stress on the diaphragm, generating electrical energy, and can be combined with other energy harvesting mechanisms like electromagnetic or electrostatic to enhance power output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If existing energy harvesters are used to convert mechanical energy from human motion to electrical energy, then power output is generated, but the transfer efficiency is low due to random and low-frequency motion
Solution Approach 1:
The energy harvester employs a dynamic mechanism that adapts to random and low-frequency human motion. The piezoelectric element is coupled with a mechanical structure that converts irregular motion into effective stress cycles, maximizing energy extraction from each motion event regardless of frequency or direction.
Solution Approach 2:
The device utilizes mechanical vibration principles where the piezoelectric material is subjected to cyclic stress through a mechanical coupling mechanism. The structure amplifies and regularizes the random motion input, creating effective vibration cycles that drive piezoelectric charge generation despite the low and variable frequency of human motion.
2Power
If a piezoelectric diaphragm with eccentric mass is used to maximize mechanical energy transfer, then power output is enhanced, but device complexity increases
Solution Approach 1:
The patent combines multiple functions into a single integrated structure. The piezoelectric diaphragm serves both as the active energy-generating element and as part of the mechanical coupling system. The eccentric mass is integrated directly into the diaphragm assembly, eliminating the need for separate coupling mechanisms and reducing overall structural complexity while maintaining enhanced power output.
Solution Approach 2:
The piezoelectric diaphragm performs multiple functions simultaneously: it acts as the piezoelectric active layer for charge generation, as a structural element for mechanical coupling, and as part of the mass distribution system through integrated eccentric mass. This multi-functionality reduces the number of separate components needed, simplifying the overall device structure.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration effectively maximizes the transfer of mechanical energy from human motion to electrical energy, providing a reliable power source for electronic devices, particularly in wearable and healthcare applications, with enhanced power output through the use of multiple piezoelectric components and reduced friction mechanisms.
Implementation Method 1
The piezoelectric stress inducer deforms the piezoelectric diaphragm in response to rotational motion of the eccentric mass, causing the piezoelectric diaphragm to generate electrical energy
Data Source
AI summary
An exemplary energy harvester includes a piezoelectric diaphragm, an eccentric mass that rotates in response to external motion, and a piezoelectric stress inducer coupled with the eccentric mass and the piezoelectric diaphragm. The piezoelectric stress inducer deforms the piezoelectric diaphragm in response to rotational motion of the eccentric mass, causing the piezoelectric diaphragm to generate electrical energy.