Multi-junction Solar Cell with Patterned Cavities for Heat Dissipation
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Solution Overview
Problem
Multi-junction solar cells face challenges with heat dissipation and lattice mismatch issues, which affect conversion efficiency and lead to wafer bending and cracking due to stress accumulation.
Innovation Solution
A novel multi-junction solar cell structure incorporating a discontinuous photoelectric converting structure, either in the form of patterned cavities or quantum dot layers, which enhances heat dissipation and mitigates stress by forming photovoltaic structures in cavities or using quantum dots to manage lattice mismatch, thereby improving efficiency and mechanical stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a lattice-matched triple junction Ge/GaAs/GaInP structure is used to achieve high conversion efficiency, then the absorption spectrum range is broadened and conversion efficiency exceeds 30%, but heat dissipation becomes difficult and stress accumulation causes wafer bending and cracking
Solution Approach 1:
The patent divides the continuous photovoltaic structure into discrete segments by creating patterned cavities that penetrate through the solar cell structure. These cavities segment the heat-generating regions and provide pathways for heat dissipation, allowing the high-efficiency multi-junction structure to maintain its conversion efficiency while reducing thermal accumulation through the segmented cavity network.
2Productivity
If a lattice-matched triple junction Ge/GaAs/GaInP structure is used to achieve high conversion efficiency, then the absorption spectrum range is broadened and conversion efficiency exceeds 30%, but lattice mismatch causes stress accumulation leading to wafer bending and cracking
Solution Approach 1:
The patterned cavities segment the stress-prone regions by creating discrete zones that relieve lattice mismatch stress. The cavities act as stress-release features that prevent continuous stress accumulation across the wafer, thereby maintaining mechanical integrity while preserving the high conversion efficiency of the multi-junction photovoltaic structure.
Solution Approach 2:
The patent introduces a porous or cavity-containing structure through the patterned cavities that penetrate the solar cell layers. This porous-like structure provides stress relief pathways and reduces the mechanical constraints imposed by lattice mismatch, preventing wafer bending and cracking while maintaining the electrical performance of the photovoltaic junctions.
3Temperature
If patterned cavities are introduced to improve heat dissipation and reduce stress, then heat dissipation and mechanical integrity are improved, but the manufacturing process becomes more complex
Solution Approach 1:
The patterned cavities serve multiple functions simultaneously: they provide heat dissipation pathways, relieve stress from lattice mismatch, and maintain structural integrity. This multi-functionality reduces the need for separate components or structures, thereby limiting the increase in overall device complexity while achieving multiple performance improvements.
Solution Approach 2:
The patent optimizes parameters such as cavity size, spacing, depth, and pattern geometry to achieve the desired heat dissipation and stress relief effects. By carefully controlling these parameters, the structure achieves improved thermal and mechanical performance without excessive complexity, as the cavity patterns can be integrated into existing manufacturing processes with adjusted process parameters.
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 proposed structure improves heat dissipation and reduces stress-related issues, enhancing the conversion efficiency and mechanical integrity of the solar cell, allowing for higher current production and reduced wafer defects.
Implementation Method 1
Ga1-xInxP (1.85 eV; x ̃0.5), which is called the top cell, has the larger band gap and is the upmost layer to absorb the photon with higher energy
Implementation Method 2
forming a photon recycling layer on the second photovoltaic structure
Data Source
AI summary
The disclosure provides a multi-junction solar cell structure and the manufacturing method thereof, comprising a first photovoltaic structure and a second photovoltaic structure; wherein at least one of the first photovoltaic structure and the second photovoltaic structure comprises a discontinuous photoelectric converting structure.