Electrochromic Devices with Bias Electrodes for Current Reduction

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Solution Overview

Problem

Existing electrochromic systems face issues with high electrical current consumption, reduced switching dynamics, and slower switching speeds due to the neutralization of electroactive substances, which limits the difference in light transmission between light and dark states and complicates manufacturing.

Innovation Solution

The introduction of bias electrodes, which are electrically insulated from supply electrodes and connected to separate electrical sources, creates an electric field that attracts oxidized and reduced electroactive substances away from each other, improving access to supply electrodes and reducing mutual neutralization, thereby enhancing switching speed and dynamics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If electroactive substances are allowed to diffuse and mutually neutralize each other in the closed volume, then the system achieves a dark state with limited light transmission saturation, but electrical current consumption increases and switching dynamics are reduced

Engineering Contradiction:
Improveelectrical current consumptionVSAvoidswitching dynamics
Core Design Contradiction:
Loss of energyVSProductivity

Solution Approach 1:

A gel matrix is introduced as an intermediary medium between the electroactive substances. This gel restricts the diffusion and movement of the electroactive substances, preventing their mutual neutralization while still allowing electron transfer reactions to occur at the electrodes. The gel acts as a mediator that maintains spatial separation of the substances, thereby reducing current consumption and improving switching dynamics.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention changes the physical state and mobility parameters of the electroactive substances by incorporating them into a gel matrix. This parameter change restricts their diffusion coefficient and movement freedom, preventing the substances from freely migrating and neutralizing each other, thus resolving the contradiction between energy loss and productivity.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If electroactive substances react in contact with supply electrodes, then the system achieves electrochromic effect, but the substances remain close to the electrode and limit access of other electroactive substances, slowing down switching speed

Engineering Contradiction:
Improveswitching speedVSAvoidsystem structure
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The gel matrix serves as an intermediary that facilitates rapid ion and electron transport between the electroactive substances and the electrodes while maintaining spatial organization. This intermediary structure enables fast switching speeds by improving mass transport kinetics without requiring complex external pumping or mixing systems.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The gel matrix provides a porous three-dimensional network structure that allows efficient diffusion pathways for electroactive substances to reach the electrodes. The porous structure increases the effective surface area and facilitates rapid mass transport, thereby increasing switching speed without adding mechanical complexity to the system.

Inventive Principle:
Principle #31Porous materials

3Illumination intensity

If reciprocal neutralization of electroactive substances occurs, then the system reaches a saturation light transmission value in dark state, but the difference between light transmission values in light and dark states is reduced

Engineering Contradiction:
Improvelight transmission contrastVSAvoidelectroactive substances concentration distribution
Core Design Contradiction:
Illumination intensityVSQuantity of substance

Solution Approach 1:

The gel matrix as an intermediary prevents the complete mixing and neutralization of electroactive substances by maintaining their spatial distribution. This allows the system to achieve higher contrast between light and dark states by preserving the concentration gradients necessary for strong electrochromic effect, without requiring changes in the total quantity of substances.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 reduces electrical current consumption, increases switching dynamics, and simplifies manufacturing by maintaining the electroactive substances' separation, preventing saturation and improving the contrast between light and dark states.

Implementation Method 1

creates an electric field that attracts oxidized and reduced electroactive substances away from each other

Methodology Applied
Scientific EffectElectric field: Electric Field

Implementation Method 2

attracts oxidized and reduced electroactive substances away from each other

Methodology Applied
Scientific EffectElectrophoresis: Electrophoresis

Implementation Method 3

an electrochromic system is a transparent element whose optical light transmission characteristics can vary in response to an electric current

Methodology Applied
Scientific EffectElectrochromism: Electrochromism

Implementation Method 4

first and second electroactive substances which are distributed in the liquid or gel, with respective oxidation-reduction potentials

Methodology Applied
Scientific EffectOxidation-reduction reactions: Redox Reactions

Data Source

PatentEP2483742B1Transparent electrochromic devices with supply electrodes and polarisation electrodes
Publication Date: 2015.05.20 ESSILOR INTERNATIONAL(COMPAGNIE GENERALE D OPTIQUE)
  • EP2483742B1 patent drawingFigure 1a~1b
  • EP2483742B1 patent drawingFigure 2a~2b
  • EP2483742B1 patent drawingFigure 3a~3b

AI summary

The invention relates to transparent electrochromic systems (100) which each include one pair of supply electrodes (1, 2) and at least one pair of polarisation electrodes (3, 4). The polarisation electrodes prevent a reaction of mutual neutralisation of the electroactive substances of the systems from causing unnecessary consumption of electric current. Said electrodes also prevent a neutralisation reaction from limiting a lower value of light transmission of the systems. For this purpose, the polarisation electrodes produce an electric field (E) inside the systems, which attracts the electroactive substances that have already reacted with the supply electrodes to different areas.