Electrostatic Induction Energy Conversion Device with Electret Coating

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Solution Overview

Problem

Conventional electrostatic induction energy conversion devices face challenges in injecting a large amount of electric charge into electrets due to charge being induced back to the base electrode, leading to decreased power generation efficiency and discharge issues, especially at low frequencies and large interelectrode gaps.

Innovation Solution

The solution involves covering the outer perimeter surface of electrodes with a coating of at least 5 µm thick electrets, burying electrodes in grooves, and applying insulating coatings to improve dielectric strength voltage, thereby preventing charge loss and discharge, and increasing surface potential for enhanced power generation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a large amount of electric charge is injected into electrets to increase power generation, then power generation amount increases, but charge is induced back to the base electrode causing discharge and degradation in power generation efficiency

Engineering Contradiction:
Improvepower generation amountVSAvoidpower generation efficiency
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The electret coating acts as an intermediary layer between the base electrode and the corona discharge needle. This coating prevents direct charge induction to the base electrode while allowing charge injection into the electret material itself, thereby maintaining power generation efficiency while enabling increased charge storage

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention changes the physical state and electrical properties of the electret material by controlling its coating thickness (5-20 µm) and material composition. This parameter optimization allows the electret to hold larger amounts of charge without discharge, resolving the contradiction between power generation amount and efficiency

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the coating thickness of electrets on electrode outer perimeter surfaces is increased to prevent charge loss, then charge retention improves, but manufacturing complexity increases

Engineering Contradiction:
Improvecharge retentionVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention optimizes the electret coating thickness to a specific range (5-20 µm) that provides sufficient charge retention while remaining compatible with existing manufacturing processes. This parameter optimization balances reliability improvement with manufacturing feasibility

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The electret coating can be applied as a thin film layer that is visually distinguishable, allowing for quality control and verification of proper coating application during manufacturing, thereby managing complexity through visual inspection methods

Inventive Principle:
Principle #32Color changes

3Reliability

If the interelectrode gap is increased to reduce discharge, then discharge occurrences decrease, but power generation efficiency decreases due to reduced electric field strength

Engineering Contradiction:
Improvedischarge preventionVSAvoidpower generation efficiency
Core Design Contradiction:
ReliabilityVSPower

Solution Approach 1:

The electret coating serves as an intermediary that enables larger interelectrode gaps without discharge. The coating's insulating properties and charge-holding capability allow the electric field to be maintained over larger distances, decoupling the relationship between gap size and discharge risk

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention changes the electrical breakdown characteristics of the interelectrode space by introducing the electret coating. This allows optimization of the interelectrode gap for power generation efficiency while the coating prevents discharge, resolving the contradiction between gap size and discharge prevention

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 approach allows for increased electric charge retention in electrets, improved power generation efficiency, and reduced discharge occurrences, resulting in a more reliable and efficient energy conversion device.

Implementation Method 1

Energy conversion devices generating power by ambient vibrations mainly come in three types; an electromagnetic induction type, a piezoelectric type, and an electrostatic induction type

Methodology Applied
Scientific EffectElectrostatic induction: Electrostatic Induction

Implementation Method 2

applying insulating coatings to improve dielectric strength voltage, thereby preventing charge loss and discharge

Methodology Applied
Scientific EffectDielectric strength: Dielectric

Implementation Method 3

an energy conversion device of an electrostatic induction type for electric power generation by using environmental vibration

Methodology Applied
Scientific EffectElectrostatic induction: Electrostatic Induction

Data Source

PatentEP2375557B1Energy conversion device of electrostatic induction type
Publication Date: 2020.01.22 OMRON CORP
  • EP2375557B1 patent drawingFigure 1
  • EP2375557B1 patent drawingFigure 2
  • EP2375557B1 patent drawingFigure 3

AI summary

On an upper surface of a fixed substrate 22, a plurality of strap-shaped base electrodes 27 are arranged in parallel to each other. On each of the base electrodes 27, an electret 28 is formed. The electret 28 has a width wider than the width of each base electrode 27, and the electret 28 covers an exposed surface of the base electrode 27. A movable substrate 23 is disposed in parallel to and facing the surface of the fixed substrate 22 where the electrets 28 and others are formed. The movable substrate 23 is movable relatively to the fixed substrate 22. On a facing surface of the movable substrate 23, strip-shaped counter electrodes 32 are each formed so as to face each base electrode 27.