Solar Cell Emitter Uniformity via Anti-Etching Masks
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Solution Overview
Problem
Conventional solar cell manufacturing methods face inefficiencies due to edge isolation processes that can damage the emitter unit and lead to shunt generation, reducing solar cell efficiency.
Innovation Solution
A method involving the use of anti-etching masks for wet edge isolation, where the masks are formed with specific designs and intervals to prevent etching of the emitter unit on the front surface, ensuring uniform sheet resistance and preventing shunt formation, combined with the formation of emitter layers with varying impurity concentrations to enhance current collection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wet edge isolation is performed without anti-etching masks, then the etching process can effectively remove emitter units from side surfaces, but the emitter unit on the front surface is damaged and shunt generation occurs
Solution Approach 1:
An anti-etching mask is introduced as an intermediary protective layer between the etching solution and the emitter unit on the front surface. The mask selectively protects the emitter unit during wet edge isolation, preventing etching damage while allowing effective removal of emitter units from side surfaces. After etching, the mask is removed, leaving the emitter unit intact and functional.
2Reliability
If the emitter unit thickness is increased to improve current collection, then more impurities are available for charge carrier generation, but the sheet resistance increases and manufacturing complexity increases
Solution Approach 1:
The emitter unit is designed with spatially varying impurity concentrations, creating different regions with optimized properties. A first region with lower impurity concentration reduces sheet resistance for better electrical contact, while a second region with higher impurity concentration enhances charge carrier generation. This local differentiation allows simultaneous optimization of current collection and sheet resistance without increasing overall thickness or manufacturing complexity.
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 improves the sheet resistance and conversion efficiency of solar cells by preventing damage to the emitter unit and reducing shunt generation, leading to enhanced power generation capabilities.
Implementation Method 1
an anti-reflective film positioned on the emitter unit
Implementation Method 2
a plurality of electron-hole pairs are generated in the semiconductor. The generated electron-hole pairs are separated into electrons and holes, having electric charges, by a photovoltaic effect
Data Source
AI summary
A solar cell includes a first conductivity type substrate; an emitter unit having a second conductivity type opposite to the first conductivity type, and forming a p-n junction with the substrate; an anti-reflective film positioned on the emitter unit; a plurality of first electrodes positioned on the anti-reflective film and connected with the emitter unit; and a second electrode connected with the substrate, wherein the emitter unit includes a first region and a second region that are positioned between an outermost first electrode among the plurality of first electrodes and the edge of the substrate, and a thickness of the first region gradually increases in going from the edge of the substrate to the outermost first electrode, and a thickness of the second region is uniform.