Electrochromic Element Asymmetric Electrode Deposition Control

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Solution Overview

Problem

Conventional electrochromic elements and devices face inefficiencies in switching between transparent and reflective states due to limitations in metal deposition and dissolution processes, particularly in controlling the deposition and dissolution voltages and rates on electrodes.

Innovation Solution

An electrochromic element comprising a first transparent electrode, a second electrode with a rougher surface, and an electrolyte containing metal, where the second deposition voltage for metal deposition on the second electrode is higher than the first deposition voltage on the first electrode, allowing for efficient metal deposition and dissolution by controlling the voltage polarity and magnitude.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If metal deposition is performed on both electrodes at the same voltage threshold, then the switching mechanism is simple, but the dissolution efficiency and switching speed are reduced

Engineering Contradiction:

Improveswitching speedVSAvoidvoltage control mechanism

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent applies local quality by creating asymmetric electrodes with different surface roughness characteristics. The first electrode has a rougher surface while the second electrode has a smoother surface, causing metal to preferentially deposit on the first electrode at lower voltages. This local structural difference enables differential deposition voltages without complex control mechanisms, thereby improving switching speed while maintaining simple voltage control.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent implements asymmetry by designing the first electrode with higher surface roughness than the second electrode. This asymmetric structure creates different nucleation sites and deposition energy barriers on each electrode, resulting in the first electrode accepting metal deposition at lower voltages while the second electrode requires higher voltages. This asymmetric design directly enables the differential voltage threshold mechanism that improves switching efficiency.

Inventive Principle:

Principle #4Asymmetry

2Productivity

If high voltage is applied to dissolve metal quickly, then switching speed improves, but power consumption increases

Engineering Contradiction:

Improveswitching speedVSAvoidpower consumption

Core Design Contradiction:

ProductivityVSUse of energy by moving object

Solution Approach 1:

The patent applies parameter changes by modifying the surface roughness parameter of the electrodes to create differential deposition characteristics. The rougher first electrode allows metal deposition at lower voltages, while the smoother second electrode requires higher voltages for deposition. This parameter difference enables efficient metal dissolution at moderate voltages, improving switching speed without requiring excessive power consumption.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If metal deposits on the second electrode, then the reflective state is achieved, but the deposition control becomes difficult and efficiency decreases

Engineering Contradiction:

Improvereflective state stabilityVSAvoiddeposition control

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent uses local quality by giving the first electrode a rougher surface texture compared to the smoother second electrode. This local structural difference creates preferential deposition sites on the first electrode, allowing metal to deposit there first at lower voltages. The controlled progression of deposition from the rough first electrode to the smooth second electrode improves deposition control while ensuring stable reflective state formation.

Inventive Principle:

Principle #3Local quality

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 enables efficient switching between transparent and reflective states by optimizing the deposition and dissolution rates, reducing power consumption and improving switching times, while maintaining low manufacturing costs and optical properties.

Implementation Method 1

metal is depositable on one of the first electrode and the second electrode, according to a voltage applied between the first electrode and the second electrode

Methodology Applied

Scientific EffectElectrochemical deposition: Electrodeposition

Data Source

PatentUS11187956B2Electrochromic element and electrochromic device

Publication Date: 2021.11.30 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD

AI summary

An electrochromic element includes: a first electrode which transmits light; a second electrode disposed opposite the first electrode; and an electrolyte containing metal and located between the first electrode and the second electrode. The metal is depositable on one of the first electrode and the second electrode, according to a voltage applied between the first electrode and the second electrode, and a second deposition voltage at which deposition of the metal on the second electrode starts is higher than a first deposition voltage at which deposition of the metal on the first electrode starts.