Variable Emissivity Electrochromic Structure for Spacecraft Thermal Control

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Solution Overview

Problem

Traditional electrochromic structures for spacecraft thermal management suffer from concurrent color changes and insufficient heat dissipation due to high solar absorption, making it difficult to efficiently control thermal radiation in extreme space environments.

Innovation Solution

A variable emissivity electrochromic structure comprising a reflecting layer, an insulating layer, and an adjusting layer, connected to a power supply, forms an optical resonant cavity to modulate infrared emissivity independently of visible color, using conductive or semiconductive materials with adjustable thickness and voltage control to optimize infrared light transmittance and absorption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If traditional electrochromic structure is used to regulate infrared emissivity, then visible color changes occur concurrently, but solar absorption increases leading to insufficient heat dissipation

Engineering Contradiction:
Improvethermal management capabilityVSAvoidsolar absorption
Core Design Contradiction:
TemperatureVSObject-affected harmful factors

Solution Approach 1:

The patent segments the control of visible and infrared properties into independent layers: the EC layer controls visible transmittance while the IC layer independently controls infrared emissivity. This segmentation allows separate optimization of visible color regulation and infrared thermal management without mutual interference, resolving the contradiction between visible color change and solar absorption.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by assigning different functional properties to different layers: the EC layer provides visible region modulation while the IC layer provides infrared region modulation. Each layer is optimized for its specific spectral region, enabling localized control of optical properties to achieve low solar absorption while maintaining thermal management capability.

Inventive Principle:
Principle #3Local quality

2Illumination intensity

If EC layer is at colored state to regulate visible light, then infrared emissivity changes concurrently, but heat dissipation becomes insufficient

Engineering Contradiction:
Improvevisible light regulationVSAvoidheat dissipation efficiency
Core Design Contradiction:
Illumination intensityVSLoss of energy

Solution Approach 1:

The patent divides the optical regulation function into two independent segments: visible light regulation by the EC layer and infrared heat dissipation regulation by the IC layer. This allows the EC layer to be at colored state for visible light regulation while the IC layer independently maintains high infrared emissivity for effective heat dissipation, eliminating the energy loss contradiction.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent uses a composite structure combining EC material and IC material in separate layers. The EC material provides visible region electrochromic modulation while the IC material provides infrared region emissivity modulation. This composite approach enables simultaneous achievement of visible light regulation and effective heat dissipation without mutual compromise.

Inventive Principle:
Principle #40Composite materials

3Ease of operation

If traditional five-layer EC structure is used, then visible color regulation is achieved, but decoupling of IR emissivity and visible color is not possible

Engineering Contradiction:
Improvevisible color controlVSAvoidindependent IR emissivity regulation
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The patent segments the control functions into independent layers: EC layer for visible color control and IC layer for independent IR emissivity regulation. This segmentation enables each layer to be controlled independently, achieving both ease of visible color operation and adaptability of independent infrared emissivity regulation simultaneously.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent creates a multi-functional structure where the EC layer handles visible region control and the IC layer handles infrared region control. This universal design allows the system to perform both visible color regulation and independent infrared emissivity regulation, enhancing adaptability while maintaining ease of operation for each function.

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

4Temperature

If reflecting layer and adjusting layer are connected to power supply with adjustable voltage, then infrared emissivity can be modulated, but device complexity increases

Engineering Contradiction:
Improveinfrared emissivity controlVSAvoidlayer structure complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The patent merges the infrared reflecting function and infrared modulating function into a single integrated structure where the IC layer serves both as the modulating element and the emitting/reflecting surface. This merging reduces the number of separate components needed compared to traditional multi-layer EC structures, achieving infrared emissivity control while minimizing device complexity.

Inventive Principle:
Principle #5Merging (Combining)

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 allows for precise control of infrared emissivity, reducing solar absorption and enhancing thermal management capabilities, with adjustable emissivity and low solar absorption rates, effectively addressing the limitations of traditional electrochromic structures.

Implementation Method 1

an optical resonant cavity structure is formed between the adjusting layer and the reflecting layer, and the optical resonant cavity is used for regulating the absorption of infrared light

Methodology Applied
Scientific EffectOptical resonance: Resonance

Implementation Method 2

the reflecting layer is used for reflecting infrared light

Methodology Applied
Scientific EffectInfrared reflection: Reflection

Implementation Method 3

By applying voltage, ions are inserted and extracted from the EC layer, there is the reversible and visible change in transmittance and/or reflectance that is associated with an electrochemically induced oxidation-reduction reaction

Methodology Applied
Scientific EffectElectrochromism: Electrochromism

Implementation Method 4

there is the reversible and visible change in transmittance and/or reflectance that is associated with an electrochemically induced oxidation-reduction reaction

Methodology Applied
Scientific EffectOxidation-reduction reaction: Redox Reactions

Data Source

PatentEP4428607A1Variable emissivity electrochromic structure
Publication Date: 2024.09.11 HARBIN INST OF TECH
  • EP4428607A1 patent drawingFigure 1~2
  • EP4428607A1 patent drawingFigure 3~4
  • EP4428607A1 patent drawing

AI summary

The present application relates to the technical field of variable emissivity electrochromic structures, in particular to a variable emissivity electrochromic structure. Embodiments of the present application provide an variable emissivity electrochromic structure, which sequentially comprises a reflecting layer, an insulating layer and an adjusting layer along the thickness direction, wherein the reflecting layer is used for reflecting infrared light, the preparation material of the reflecting layer comprises a conductor or a semiconductor; the preparation material of the adjusting layer comprises a conductor or a semiconductor with infrared semitransparent property; the reflecting layer and the adjusting layer are respectively connected to two electrodes of a power supply, and the voltage can be adjusted; an optical resonant cavity structure is formed between the adjusting layer and the reflecting layer, and the optical resonant cavity is used for adjusting and controlling the absorption of infrared light; the infrared transmittance and absorption of the adjusting layer can be altered by adjusting the voltage of the power supply, so as to adjust the amount of infrared light entering the optical resonant cavity structure, and further adjust the infrared emissivity of the variable emissivity electrochromic structure. The embodiments of the present application provide a variable emissivity electrochromic structure, which can provide a structure with an adjustable IR emissivity. In addition, the novel variable emissivity electrochromic structure of the present application has the following advantages: a) low solar absorption; b) visible transparent; c) decoupling of the dynamic regulation of IR emissivity and visible color; d) controllable IR emissivity in initial state.