RF Transparent Photovoltaic Cell Back Contact Apertures

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Solution Overview

Problem

Conventional photovoltaic cells are opaque to radio frequency electromagnetic radiation, which can interfere with the operation of radar units and other devices that require transparency, such as airships with internal antennas, limiting their application and efficiency in power generation.

Innovation Solution

A photovoltaic cell design featuring a back contact layer with strategically placed apertures that allow radio frequency electromagnetic radiation to pass through, ensuring the cell is at least partially transparent to specific frequencies while maintaining electrical conductivity and efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a solid metallic back contact layer is used in PV cells, then electrical conductivity and power generation efficiency are improved, but radio frequency electromagnetic radiation transparency deteriorates

Engineering Contradiction:

Improvepower generation efficiencyVSAvoidradio frequency electromagnetic radiation blocking

Core Design Contradiction:

PowerVSObject-affected harmful factors

Solution Approach 1:

The solid metallic back contact layer is segmented into a grid pattern of conductive strips separated by apertures. This segmentation allows RF electromagnetic radiation to pass through the apertures while the conductive strips maintain electrical conductivity for power collection. The grid structure divides the continuous metal layer into discrete elements that fulfill both electrical and RF transparency requirements.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the back contact layer are assigned different functions: the conductive strips provide electrical conductivity for power collection, while the aperture regions provide RF electromagnetic radiation transparency. This local differentiation of properties allows the single layer to simultaneously satisfy both electrical and RF requirements that would be contradictory in a uniform structure.

Inventive Principle:

Principle #3Local quality

2Power

If PV cells are placed on the outer surface of radar units, then power generation from sunlight is improved, but radar operation is interfered with due to RF opacity

Engineering Contradiction:

Improvesunlight power generationVSAvoidradar operation interference

Core Design Contradiction:

PowerVSObject-generated harmful factors

Solution Approach 1:

The back contact layer is segmented into conductive strips and apertures, allowing RF radiation to pass through the aperture regions while sunlight continues to reach the PV cell for power generation. This segmentation resolves the conflict between maintaining electrical functionality and enabling RF transparency for radar operations.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The back contact layer exhibits local quality differentiation where conductive strips provide electrical conductivity for power collection while aperture regions provide RF transparency. This allows the PV cell to simultaneously generate power from sunlight and permit radar RF radiation to pass through without interference.

Inventive Principle:

Principle #3Local quality

3Illumination intensity

If transparent materials like zinc oxide or indium tin oxide are used for the back contact layer, then light transparency is improved, but radio frequency electromagnetic radiation transparency remains poor

Engineering Contradiction:

Improvelight transparencyVSAvoidradio frequency electromagnetic radiation blocking

Core Design Contradiction:

Illumination intensityVSObject-affected harmful factors

Solution Approach 1:

The invention changes the structural parameters of the back contact layer from a solid continuous layer to a grid pattern with apertures. This parameter change enables both light transparency (for PV operation) and RF electromagnetic radiation transparency simultaneously, overcoming the limitation of transparent materials that block RF radiation.

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

Enables the use of photovoltaic cells on airships and other applications where radio frequency transparency is required, increasing the surface area for power generation and improving efficiency by allowing radio frequency radiation to pass through, thus overcoming the limitations of conventional opaque cells.

Implementation Method 1

Photovoltaic cells ('PV cells') convert light, such as sunlight, into an electric current

Methodology Applied

Scientific EffectPhotovoltaic effect: Photovoltaic Effect

Implementation Method 2

A back contact layer with strategically placed apertures that allow radio frequency electromagnetic radiation to pass through

Methodology Applied

Scientific EffectElectromagnetic radiation transmission:

Data Source

PatentUS10971637B2Airship with a radio frequency transparent photovoltaic cell

Publication Date: 2021.04.06 RAYTHEON CO

AI summary

A radio frequency transparent photovoltaic cell includes a back contact layer formed of an electrically conductive material, at least one aperture formed in the back contact layer, and at least one photovoltaic cell section disposed on the back contact layer. An airship includes one or more radio frequency antennas disposed in an interior of the airship. One or more radio frequency transparent photovoltaic cells are disposed on an outer surface of the airship.