Solar Cell Selective Emitter and Plated Electrodes
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Solution Overview
Problem
Conventional solar cells face challenges in reducing contact resistance and increasing junction strength, which affects their efficiency, and the manufacturing process is complex and costly.
Innovation Solution
A solar cell design featuring a selective emitter region with lightly and heavily doped regions, a dielectric layer with specific openings, and a conductive metal layer formed using a plating method, which reduces contact resistance and enhances junction strength, while simplifying the manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional solar cell structures are used, then manufacturing process is simpler, but contact resistance is high and junction strength is low
Solution Approach 1:
The dielectric layer is segmented into multiple regions with different opening patterns: first openings (line shape) positioned under finger electrodes and second openings (dot shape) positioned under bus bar electrodes. This segmentation allows optimized electrical contact at different locations, reducing contact resistance while maintaining manageable structural complexity through systematic design
Solution Approach 2:
Different regions of the dielectric layer are designed with different opening characteristics: line-shaped first openings for finger electrode areas and dot-shaped second openings for bus bar electrode areas. This local differentiation optimizes the electrical connection properties at each location, achieving low contact resistance and high junction strength where needed without unnecessarily complicating the entire structure
2Reliability
If conventional electrode connection methods are used, then contact resistance is high, but manufacturing process is less complex
Solution Approach 1:
The patent replaces conventional screen printing or evaporation methods with an electroplating process to form conductive metal layers. This substitution enables precise control of metal deposition through electrochemical reactions, achieving lower contact resistance and better adhesion to the semiconductor substrate while maintaining ease of manufacture through a well-established industrial process
3Reliability
If selective emitter region with different doped regions is implemented, then junction strength increases, but manufacturing process becomes more complex
Solution Approach 1:
The emitter region is designed with spatially varying doping characteristics: heavily doped regions directly beneath electrode contact points and lightly doped regions in between. This local quality differentiation strengthens the junction at critical contact areas while maintaining appropriate electrical properties in active regions, achieving high junction strength without excessive overall complexity
Solution Approach 2:
The emitter region is segmented into functionally distinct zones: heavily doped contact regions for electrical connection and lightly doped active regions for photovoltaic function. This segmentation allows each zone to be optimized for its specific purpose, achieving high junction strength at contacts while preserving device performance
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 design improves the efficiency of solar cells by reducing contact resistance and increasing junction strength, while also reducing manufacturing costs and complexity.
Implementation Method 1
When light is incident on the solar cell having the above-described structure, electrons inside the semiconductors become free electrons (hereinafter referred to as 'electrons') by the photoelectric effect.
Implementation Method 2
Further, electrons and holes respectively move to the n-type semiconductor (for example, the emitter region) and the p-type semiconductor (for example, the substrate) based on the principle of the p-n junction.
Implementation Method 3
the first electrode includes a seed layer positioned on the surface of the selective emitter region exposed through the first and second openings and a conductive metal layer positioned on the seed layer
Data Source
AI summary
A solar cell includes a substrate, a selective emitter region which is positioned at the substrate and includes a lightly doped region and a heavily doped region, a first dielectric layer which is positioned on the selective emitter region and includes a plurality of first openings, which are separated from one another, and a plurality of second openings positioned around the plurality of first openings, a first electrode connected to the selective emitter region through the plurality of first openings and the plurality of second openings, and a second electrode which is positioned on the substrate and is connected to the substrate. The plurality of first openings and the plurality of second openings each have a different plane shape. The plane shape of the first opening has a line shape, and the plane shape of the second opening has a dot shape.