Multi-Junction Solar Cell Optical Power Feeding in Low-Sunlight Conditions
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Solution Overview
Problem
Vehicles and mobile bodies equipped with solar photovoltaic power generation panels face energy shortages during insufficient sunlight conditions, such as nighttime, cloudy weather, or shaded areas, as they rely solely on solar energy for operation, necessitating a non-contact method to supplement electric power.
Innovation Solution
A method and device for non-contact electric power feeding using a light-projecting device that emits light containing wavelength components absorbed by each solar cell layer in a multi-junction solar cell, ensuring all layers generate electric current and power, even in the absence of sufficient sunlight, by irradiating the solar photovoltaic power generation panel with artificially generated light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single junction photoelectric conversion element is used for non-contact power feeding, then the device structure is simple, but the energy conversion efficiency is low
Solution Approach 1:
The photoelectric conversion element is divided into multiple junction layers (first junction, second junction, third junction) with different band gaps, allowing each layer to convert light of different wavelengths independently, thereby increasing overall energy conversion efficiency while maintaining a structured but manageable device architecture
Solution Approach 2:
The patent employs a multi-junction solar cell structure combining different semiconductor materials (InGaP, InGaAs, Ge) with varying band gaps to create a composite photoelectric conversion element that efficiently converts a broader spectrum of light into electricity, resolving the contradiction between structural simplicity and conversion efficiency
2Loss of energy
If a multi-junction solar cell is used to improve energy conversion efficiency, then the photoelectric conversion efficiency increases, but the device complexity increases
Solution Approach 1:
The multi-junction solar cell is segmented into distinct functional layers (InGaP top cell, InGaAs middle cell, Ge bottom cell) where each layer handles specific wavelength ranges, allowing the complex structure to be managed through clear functional division and independent optimization of each junction
Solution Approach 2:
The multi-junction solar cell structure serves multiple functions simultaneously: it converts different wavelength bands of light into electricity, provides non-contact power feeding capability, and can be integrated into existing vehicle systems, thereby justifying the increased structural complexity through multiple beneficial functions
3Device complexity
If sunlight is the only energy source for vehicles, then the system is simple, but the reliability of power supply decreases during insufficient sunlight conditions
Solution Approach 1:
The patent introduces an external light source (laser or LED) as an intermediary to deliver optical energy to the solar cell when natural sunlight is insufficient, enabling continuous power generation and improving supply reliability without fundamentally changing the vehicle's power generation system
Solution Approach 2:
The system prepares for insufficient sunlight conditions by having an external light source ready to illuminate the solar cell proactively, ensuring continuous power generation before complete darkness or heavy cloud cover occurs, thereby maintaining reliable power supply
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 approach allows for efficient non-contact electric power generation and supply to vehicles and mobile bodies, ensuring continuous operation by converting the irradiated light into electrical energy, reducing energy loss and enhancing photoelectric conversion efficiency.
Implementation Method 1
a plurality of solar cell layers (layered photoelectric conversion elements) having mutually different energy band gaps are laminated and joined so as to use the sunlight energy that a photovoltaic power generation panel receives as efficiently as possible
Implementation Method 2
not only the light component of a certain specific wavelength band but also the light components of two or more wavelength bands within the sunlight covering a wide range of wavelength band can be converted into electricity with a small voltage loss
Data Source
AI summary
There are provided a method and a device for feeding electric power to a vehicle, etc. installed with a solar photovoltaic power generation panel employing a multi-junction solar cell in a non-contact manner by irradiating light to the solar photovoltaic power generation panel. In the method, light containing a wavelength component absorbed by each of all solar cell layers laminated in a multi-junction solar cell of the vehicle, etc. is projected from a light-projecting device to the light receiving surface of the multi-junction solar cell; and electric power generated by the irradiation of light from the multi-junction solar cell is taken out. The device includes structures for emitting light containing a wavelength component absorbed by each solar cell layer laminated in the multi-junction solar cell, and for irradiating the light to a light receiving surface of the multi-junction solar cell.