Wire-Based Solar Cell Stringing Without Busbars
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Solution Overview
Problem
Current solar cell manufacturing techniques face challenges in increasing efficiency and simplifying the process, particularly in the stringing of back-contact solar cells, which often involve complex metal ribbons and busbars that reduce efficiency and increase costs.
Innovation Solution
The use of wire-based metallization and stringing techniques, where conductive wires are directly bonded to the back surface of solar cells using thermocompression or ultrasonic bonding, eliminating the need for busbars and simplifying the manufacturing process by directly connecting P-type and N-type doped diffusion regions across cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If complex metal ribbons and busbars are used for stringing back-contact solar cells, then electrical connectivity is ensured, but manufacturing complexity increases and efficiency decreases
Solution Approach 1:
The patent extracts and eliminates the complex metal ribbons and busbars from the stringing structure, replacing them with simple wire-based connections. This removal of unnecessary components directly reduces manufacturing complexity while maintaining electrical connectivity through the simplified wire-based metallization approach.
Solution Approach 2:
The patent segments the metallization function into discrete wire-based contacts that can be independently applied to P-type and N-type doped diffusion regions. This segmentation allows for simpler, more modular manufacturing processes compared to the integrated complex busbar structures, enabling separate handling and attachment of conductive elements.
2Ease of manufacture
If complex metal ribbons and busbars are used for stringing, then electrical connectivity is maintained, but material usage increases and costs rise
Solution Approach 1:
The patent removes excessive material usage by eliminating complex metal ribbons and busbars, retaining only the essential wire-based connections needed for electrical connectivity. This extraction of unnecessary material directly reduces production costs while maintaining functional performance.
Solution Approach 2:
The patent applies metallization locally at specific P-type and N-type doped diffusion regions using simple wire contacts rather than extensive metal ribbons and busbars. This localized approach reduces overall material consumption while maintaining electrical connectivity where it is most needed, thereby reducing production costs.
3Ease of manufacture
If wire-based metallization is used, then manufacturing complexity is reduced, but bonding adhesion must be maintained
Solution Approach 1:
The patent employs ultrasonic bonding to create strong adhesion between wires and solar cell surfaces. The ultrasonic vibration generates localized mechanical energy that facilitates metallurgical bonding, ensuring reliable adhesion while maintaining the manufacturing simplicity of the wire-based approach.
Solution Approach 2:
The patent utilizes thermocompression bonding that involves changing temperature and pressure parameters to achieve strong adhesion. By controlling thermal and mechanical parameters during the bonding process, reliable bonding is achieved without requiring complex manufacturing procedures, maintaining both simplicity and reliability.
4Loss of substance
If wire-based metallization is used, then material usage is minimized, but manufacturing precision is required
Solution Approach 1:
The patent replaces manual or mechanical positioning methods with automated wire bonding systems that use ultrasonic or thermocompression bonding mechanisms. This substitution enables precise wire placement and bonding through controlled mechanical and thermal fields, achieving high manufacturing precision while minimizing material usage.
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 enhances solar cell efficiency by reducing manufacturing complexity, minimizing material usage, and lowering production costs while maintaining high adhesion and conductivity, thus improving overall module performance.
Implementation Method 1
conductive wires are directly bonded to the back surface of solar cells using thermocompression or ultrasonic bonding
Implementation Method 2
conductive wires are directly bonded to the back surface of solar cells using thermocompression or ultrasonic bonding
Data Source
AI summary
Wire-based metallization and stringing techniques for solar cells, and the resulting solar cells, modules, and equipment, are described. In an example, a substrate has a surface. A plurality of N-type and P-type semiconductor regions is disposed in or above the surface of the substrate. A conductive contact structure is disposed on the plurality of N-type and P-type semiconductor regions. The conductive contact structure includes a plurality of conductive wires, each conductive wire of the plurality of conductive wires essentially continuously bonded directly to a corresponding one of the N-type and P-type semiconductor regions.