Solar Cell Front Sheet with Cholesteric Liquid Crystal IR Blocking

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Solution Overview

Problem

Existing solar cell photovoltaic modules face efficiency degradation due to increased operating temperature, particularly caused by infrared radiation, which is not effectively blocked by current IR blocking technologies, leading to higher costs and reduced transmittance in visible radiation regions.

Innovation Solution

A multi-layered sheet comprising a substrate with an IR blocking layer made of cholesteric liquid crystal material and a UV blocking layer containing a fluorine-based polymer and wavelength conversion material is used as a front sheet for solar cells, effectively blocking IR radiation and converting UV radiation to improve power generation efficiency while maintaining transmittance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a transparent inorganic oxide is deposited on the photovoltaic cell to block IR radiation, then temperature increase is suppressed, but manufacturing cost increases due to multi-layered vapor deposition process

Engineering Contradiction:

Improvecell temperatureVSAvoidmanufacturing cost

Core Design Contradiction:

TemperatureVSEase of manufacture

Solution Approach 1:

The patent changes the material parameter from transparent inorganic oxide to cholesteric liquid crystal material, which inherently blocks IR radiation through its helical structure without requiring complex multi-layered vapor deposition processes. This material substitution maintains temperature control while simplifying manufacturing.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses composite material structure combining cholesteric liquid crystal material with polymer matrix, creating a material that simultaneously provides IR blocking capability and ease of manufacturing through solution processing rather than complex physical vapor deposition.

Inventive Principle:

Principle #40Composite materials

2Productivity

If IR blocking layer is added to suppress temperature increase, then power generation efficiency is improved, but transmittance in visible radiation region deteriorates

Engineering Contradiction:

Improvepower generation efficiencyVSAvoidvisible radiation transmittance

Core Design Contradiction:

ProductivityVSIllumination intensity

Solution Approach 1:

The cholesteric liquid crystal material exhibits selective optical properties where it blocks IR radiation (wavelengths longer than visible light) while maintaining high transmittance in the visible radiation region. This local quality differentiation allows simultaneous achievement of temperature control and visible light transmission.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent utilizes the optical property of cholesteric liquid crystal materials that can selectively reflect or block specific wavelength ranges (IR region) while allowing other wavelengths (visible region) to pass through, effectively using wavelength-selective transmission to resolve the contradiction.

Inventive Principle:

Principle #32Color changes

3Temperature

If conventional IR blocking materials are used, then IR radiation is blocked, but heat is generated due to absorption

Engineering Contradiction:

Improvecell temperature controlVSAvoidheat generation

Core Design Contradiction:

TemperatureVSLoss of energy

Solution Approach 1:

Instead of absorbing IR radiation and converting it to heat (which causes temperature increase), the cholesteric liquid crystal material reflects IR radiation away from the cell. This converts the harmful IR energy into reflected energy that does not contribute to heating, effectively eliminating the heat generation problem while maintaining IR blocking functionality.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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

The solution effectively suppresses temperature increases in solar cells, enhances power generation efficiency, and improves weather resistance by selectively blocking IR radiation and converting UV radiation, thereby improving the overall performance and longevity of solar cell modules.

Implementation Method 1

an IR blocking layer which is formed on one surface of the substrate and includes a cholesteric liquid crystal (CLC) material

Methodology Applied

Scientific EffectCholesteric liquid crystal reflection: Cholesteric Liquid Crystal

Implementation Method 2

a UV blocking layer which is formed on the IR blocking layer and includes a fluorine-based polymer and a wavelength conversion material

Methodology Applied

Scientific EffectWavelength conversion: Photoluminescence

Data Source

PatentUS9478678B2Front sheet of solar cell, method of manufacturing the same and photovoltaic module comprising the same

Publication Date: 2016.10.25 LG CHEM LTD

AI summary

A front sheet of solar cell, a method of manufacturing the same and a photovoltaic module are provided. The front sheet of solar cell can effectively block infrared rays (IRs) by forming an IR blocking layer including a cholesteric liquid crystal (CLC) material on a substrate. Thus, an increase in temperature of a cell can be suppressed so that the power generation efficiency of the cell can be improved. Also, the multi-layered sheet can be configured so that a UV blocking layer including a fluorine-based polymer and a wavelength conversion material can be formed on the IR blocking layer. Thus, wavelengths of a UV region can be converted into wavelengths of a VR region so that the power generation efficiency of the cell can be improved, and discoloration and deformation caused by UVs can be prevented so that the weather resistance can be improved.