Solar Cell Backside Busbar Bridge Layout for Better Metallization
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Solution Overview
Problem
Current metallization methods for solar cells are inefficient in forming conductive contacts, which affects the overall efficiency and cost-effectiveness of solar cell manufacturing and performance.
Innovation Solution
The method involves forming semiconductor regions and contact fingers on a substrate, followed by bonding conductive foils or plating metals to create conductive busbars and bridges, using techniques such as laser welding, thermocompression, or ultrasonic bonding, to enhance electrical connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional metallization methods are used for forming conductive contacts, then the manufacturing process is simpler, but the electrical connection efficiency and cost-effectiveness deteriorate
Solution Approach 1:
The conductive contact structure is segmented into multiple functional layers: contact fingers, conductive paste, and metallization layers (silver paste, aluminum paste). This segmentation allows each layer to perform its specific function optimally, improving electrical connection efficiency while maintaining manufacturing feasibility through specialized processing for each layer type.
Solution Approach 2:
The patent employs composite metallization structures combining different materials (silver, aluminum, copper, nickel) with complementary properties. Silver provides high conductivity, aluminum offers good adhesion and cost benefits, copper enhances conductivity, and nickel provides corrosion resistance. This composite approach resolves the contradiction by achieving superior electrical connection efficiency through material optimization while using established manufacturing techniques.
2Reliability
If advanced bonding techniques (laser welding, thermocompression, ultrasonic bonding) are used to enhance electrical connections, then the electrical connection efficiency improves, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The metallization structure is designed to self-optimize electrical connections through its multi-layer composition and geometric configuration. The contact fingers are positioned to maximize electrical contact area, and the conductive paste formulation automatically adjusts during firing to create optimal conductive pathways. This self-service approach achieves high electrical connection efficiency without requiring complex external bonding equipment or processes.
Solution Approach 2:
The patent optimizes electrical connection efficiency by carefully controlling material parameters (paste composition, layer thickness, material purity) and process parameters (firing temperature, sintering time, deposition conditions) rather than introducing complex bonding techniques. These parameter optimizations achieve superior electrical performance while maintaining manufacturing simplicity through conventional solar cell fabrication processes.
3Reliability
If multiple metallization layers are applied to improve electrical connections, then the electrical conductivity improves, but the manufacturing cost and process complexity increase
Solution Approach 1:
The metallization structure applies different material qualities to different locations and functions: silver paste is applied where maximum conductivity is needed (contact fingers and busbars), aluminum paste is used for adhesion layers and less critical conductive paths, and copper/nickel are selectively applied for specific electrical or corrosion resistance requirements. This local quality approach optimizes electrical conductivity where needed while reducing material costs in less critical areas, resolving the contradiction between conductivity and manufacturing cost.
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 increases the efficiency and cost-effectiveness of solar cell manufacturing by improving the formation of conductive contacts, leading to better electrical connections and enhanced solar cell performance.
Implementation Method 1
bonding conductive foils or plating metals to create conductive busbars and bridges, using techniques such as laser welding
Implementation Method 2
bonding conductive foils or plating metals to create conductive busbars and bridges, using techniques such as laser welding, thermocompression, or ultrasonic bonding
Implementation Method 3
bonding conductive foils or plating metals to create conductive busbars and bridges, using techniques such as laser welding, thermocompression, or ultrasonic bonding
Implementation Method 4
bonding conductive foils or plating metals to create conductive busbars and bridges
Data Source
AI summary
Methods of fabricating a solar cell including metallization techniques and resulting solar cells, are described. In an example, forming a first semiconductor region and a second semiconductor region on the back side of a substrate. A first conductive busbar can be formed above the first semiconductor region. A first portion of a second conductive busbar can be formed above the second semiconductor region. A second portion of the second conductive busbar can be formed above the second semiconductor region, where a separation region separates the second portion and the first portion of the second conductive busbar. A third conductive busbar can be formed above the first semiconductor region. A first conductive bridge can be formed above the separation region, where the first conductive bridge electrically connects the first conductive busbar to the third conductive busbar.