Solar Cell String Interconnects With Laser Metallization and Strain Relief
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current solar cell manufacturing techniques face challenges in increasing efficiency and reducing manufacturing costs, particularly in effectively connecting solar cells and forming circuits while addressing mechanical and electrical requirements, especially when using thin foils and laser-assisted metallization processes.
Innovation Solution
The implementation of laser-assisted metallization patterning (LAMP) techniques for depositing and patterning metal on solar cells, combined with strain relief features and thermocompression bonding, to enhance the connection and circuit formation between solar cells, including the use of overhang portions and interconnects with strain relief features to manage mechanical stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional metallization techniques are used to connect solar cells, then manufacturing process is simpler, but conversion efficiency is lower and manufacturing cost per Watt is higher
Solution Approach 1:
The patent combines multiple functions into the interconnect structure: electrical conduction, mechanical bonding, and strain relief are integrated into a single component. The laser-assisted metallization process also merges deposition and patterning operations, improving efficiency while managing manufacturing complexity through functional integration.
Solution Approach 2:
The patent employs laser-assisted metallization which changes the physical parameters of the metal foil through localized heating, enabling controlled deposition and bonding. This parameter change approach allows precise control over metallization quality, improving conversion efficiency while maintaining manufacturability through controlled process parameters.
2Ease of manufacture
If thin foils are used for interconnects, then manufacturing cost is reduced, but mechanical stress management becomes more difficult
Solution Approach 1:
The patent introduces strain relief features that add dimensional complexity to the interconnect structure, creating out-of-plane geometry to accommodate mechanical stress. This dimensional change allows thin foils to maintain mechanical integrity by distributing stress across three-dimensional structures rather than relying solely on foil thickness.
Solution Approach 2:
The interconnect is segmented into distinct functional regions: bonding portions for electrical connection and strain relief portions for mechanical accommodation. This segmentation allows the thin foil to be optimized for electrical conductivity in bonding regions while having dedicated strain relief regions that provide mechanical strength without requiring increased foil thickness.
3Reliability
If laser-assisted metallization is implemented, then conversion efficiency and interconnect reliability improve, but manufacturing process complexity increases
Solution Approach 1:
The patent replaces conventional mechanical metallization processes with laser-assisted metallization, using optical energy instead of mechanical contact for metal deposition and bonding. This substitution improves interconnect reliability through more precise and controlled metallization while the laser process itself integrates multiple functions (deposition, patterning, bonding) to manage overall process complexity.
Solution Approach 2:
The laser-assisted metallization process is designed to perform multiple functions: depositing metal, patterning the interconnect geometry, creating bonding surfaces, and forming strain relief features. This multi-functionality reduces the number of separate manufacturing steps needed, offsetting the complexity of implementing laser technology with the elimination of multiple conventional process steps.
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 solar cell conversion efficiency and reduces manufacturing costs by enabling more efficient metallization, better mechanical stress management, and reliable interconnects, leading to improved performance and durability of solar cell strings.
Implementation Method 1
exposing a metal foil to a laser beam over selected portions of the semiconductor substrates
Implementation Method 2
thermocompression bonding, to enhance the connection and circuit formation between solar cells
Data Source
AI summary
Strings of solar cells having laser assisted metallization conductive contact structures, and their methods of manufacture, are described. For example, a solar cell string includes a first solar cell having a front side and a back side, and one or more laser assisted metallization conductive contact structures electrically connecting a first metal foil to the back side of the first solar cell. The solar cell string also includes a second solar cell having a front side and a back side, and one or more laser assisted metallization conductive contact structures electrically connecting a second metal foil to the back side of the second solar cell. The solar cell string also includes a conductive interconnect coupling the first and second solar cells, the conductive interconnect including a strain relief feature.