Piezoelectric Power Generating Device with Segmented Cantilevers

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Solution Overview

Problem

The unimorph structure in piezoelectric generating apparatuses has a low power generating efficiency due to the small volume ratio of piezoelectric elements, limiting the effective conversion of mechanical force into electric energy.

Innovation Solution

A piezoelectric generating apparatus with multiple piezoelectric bodies arranged at intervals, each with a fixed and free end, supported by a single-plane surface and connected in series or parallel, and a weight spanning the piezoelectric bodies to enhance power generation efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a unimorph structure with a single piezoelectric capacitor on a cantilever is used, then the device structure is simple, but the power generating efficiency is low due to small volume ratio of piezoelectric elements

Engineering Contradiction:
Improvestructure simplicityVSAvoidpower generating efficiency
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The piezoelectric generating apparatus is divided into multiple piezoelectric bodies (first, second, third, and fourth piezoelectric bodies) arranged in series. Each piezoelectric body functions as an independent generating unit, increasing the total generating capacity while maintaining manageable structural complexity through modular segmentation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from a single-plane cantilever structure to a three-dimensional arrangement where piezoelectric bodies are stacked vertically and connected in series. This dimensional expansion increases the volume ratio of piezoelectric elements within the apparatus, directly improving power generating efficiency.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Productivity

If multiple piezoelectric bodies are arranged in series with a weight spanning them, then the power generating efficiency increases, but the device complexity increases

Engineering Contradiction:
Improvepower generating efficiencyVSAvoidnumber of components
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

Multiple piezoelectric bodies are merged into a single integrated series connection structure. The first and second piezoelectric bodies are connected in series, as are the third and fourth piezoelectric bodies, creating a unified generating system that increases efficiency while managing complexity through systematic integration.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The weight serves multiple functions: it applies mechanical stress to all piezoelectric bodies simultaneously, provides structural support for the series arrangement, and enables the conversion of mechanical energy to electrical energy across all units. This multi-functionality reduces the need for additional components.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Power

If the piezoelectric bodies are connected in series, then the output voltage increases, but the internal resistance increases

Engineering Contradiction:
Improveoutput voltageVSAvoidinternal resistance
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The patent employs parameter optimization in the piezoelectric material selection and geometric configuration to balance the voltage output and internal resistance. By carefully selecting piezoelectric coefficients and arranging bodies in series, the system achieves high output voltage while managing internal resistance through optimized material and structural parameters.

Inventive Principle:
Principle #35Parameter changes

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 increases the number of generating units per volume, resulting in higher power generating efficiency and the ability to produce a large power output, as demonstrated by increased output voltage and current when subjected to mechanical stress.

Implementation Method 1

Micro-piezoelectric power generation is a system for converting mechanical force, such as vibrations or shocks, into electric energy

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentEP2410649B1Piezoelectric power generating device
Publication Date: 2017.05.17 FUJITSU LTD
  • EP2410649B1 patent drawingFigure 1~2
  • EP2410649B1 patent drawingFigure 3A~3D
  • EP2410649B1 patent drawingFigure 3E~3G

AI summary

A piezoelectric generating apparatus having a high power generating efficiency is provided. The piezoelectric generating apparatus includes a plurality of piezoelectric bodies 2a arranged at intervals via a gap 2b and having a fixed end and a free end, a first surface electrode 3 formed on one side of each of the plurality of piezoelectric bodies 2a, a second surface electrode 4 formed on an opposite side of each of the plurality of piezoelectric bodies 2a, and a weight 7 spanning the plurality of piezoelectric bodies 2a and attached to the free ends of the plurality of piezoelectric bodies 2a. The plurality of piezoelectric bodies 2a are curved by applying acceleration to the weight 7 from the outside in a lateral direction.