Piezoelectric Power Generator with Variable Rigidity Laminate
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Solution Overview
Problem
Existing piezoelectric power generators face challenges in achieving uniform stress distribution across piezoelectric elements, leading to potential breakage of the fixed portion and suboptimal power generation efficiency, particularly due to concentrated stress and size limitations.
Innovation Solution
A piezoelectric power generator design featuring a laminate structure with rectangular-shaped elements connected at both ends, where each element's rigidity decreases from the fixed portion to the free end, ensuring uniform stress distribution and improved power generation efficiency through adjustable substrate thickness, width, length, material, and density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a cantilever is made long in length to increase power generation amount, then power generation efficiency improves, but the device size becomes large
Solution Approach 1:
The piezoelectric substrate is divided into multiple piezoelectric elements connected in series, allowing each element to be shorter while collectively achieving high power generation output
Solution Approach 2:
The invention transitions from a single long cantilever to a stacked configuration of multiple shorter elements, utilizing the vertical dimension to achieve both compact size and high power generation efficiency
2Length of moving object
If piezoelectric elements are stacked in a compact configuration to reduce size, then device size decreases, but stress concentrates on the fixed end causing breakage
Solution Approach 1:
Each piezoelectric element is designed with non-uniform thickness, being thinner at the fixed end and thicker at the free end, creating local structural optimization that distributes stress uniformly across all elements
Solution Approach 2:
The thickness parameter of each piezoelectric element is varied along its length, with the fixed end being thinner to reduce stress concentration and the free end being thicker to maintain structural integrity
3Productivity
If a single long cantilever is used to increase power generation, then power generation efficiency improves, but stress concentration occurs at the fixed portion
Solution Approach 1:
The single long cantilever is segmented into multiple shorter piezoelectric elements stacked in series, distributing the stress load across multiple components while maintaining overall power generation efficiency
Solution Approach 2:
Each element features localized thickness variation with the fixed end being thinner, creating optimal stress distribution characteristics at the critical fixed portion while maintaining adequate strength
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
The solution effectively disperses stress across piezoelectric elements, preventing breakage at the fixed portion and enhancing power generation efficiency while maintaining a compact size, with the ability to adjust rigidity parameters for optimal performance.
Implementation Method 1
piezoelectric power generator that extract electrical power by converting kinetic energy inputted from the outside, into electrical energy using a piezoelectric element
Data Source
AI summary
A piezoelectric power generator that includes a piezoelectric laminate in which a plurality of rectangular-shaped piezoelectric elements each having electrodes formed on a substrate are connected at both ends thereof to each other, and in which a portion other than connection portions is capable of vibrating. In the piezoelectric laminate, a portion of the element at the uppermost layer is a fixed portion, and a weight is mounted to the element (free end) at the lowermost layer. Each piezoelectric element is decreased in rigidity from the element at the uppermost layer toward the element at the lowermost layer.