Back-Contact Solar Cell Wire Stringing Without Busbars
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Solution Overview
Problem
Existing solar cell manufacturing techniques face challenges in achieving high efficiency and cost-effectiveness due to the use of busbars and metal ribbons that reduce overall efficiency and increase manufacturing complexity, particularly in back-contact solar cells.
Innovation Solution
The use of continuous conductive wires directly bonded to P-type and N-type doped diffusion regions in solar cells, with selective cutting to restore separate electrodes, eliminates the need for busbars and simplifies the manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If busbars and metal ribbons are used for electrical contact in solar cells, then electrical conductivity is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent segments the electrical contact system by replacing continuous busbars with discrete wire bonds connected to individual contact points. This segmentation simplifies manufacturing while maintaining electrical conductivity through multiple localized wire-to-contact connections rather than requiring complex continuous metal structures.
Solution Approach 2:
The patent extracts and eliminates the busbar component entirely, replacing it with direct wire bonds to contact points on the solar cell substrate. This extraction removes the manufacturing complexity associated with busbar fabrication and integration while preserving the essential electrical conduction function through simplified wire-to-contact connections.
2Reliability
If busbars and metal ribbons are used for electrical contact in solar cells, then electrical conductivity is improved, but manufacturing cost increases
Solution Approach 1:
The patent employs inexpensive wire materials and simple bonding processes替代 expensive busbar fabrication and integration. The wire bonds, while individually small, collectively provide the necessary electrical conductivity at a lower manufacturing cost due to the simplicity of wire handling, positioning, and bonding compared to busbar processing.
Solution Approach 2:
By extracting and removing the busbar component from the system, the patent eliminates the associated manufacturing costs for busbar production, handling, and integration. The direct wire-to-contact approach reduces material and process costs while maintaining electrical conductivity through multiple localized connection points.
3Reliability
If conventional metallization techniques are used, then electrical contact is achieved, but shading losses increase
Solution Approach 1:
The patent segments the electrical contact into discrete points on the substrate surface rather than using continuous metal layers. This segmentation allows for minimal disruption to the underlying semiconductor structure and reduces the total metal surface area that could cause shading losses, while maintaining adequate electrical contact through localized wire bonds.
Solution Approach 2:
The patent applies metallization only at specific local contact points where electrical connection is needed, rather than using extensive continuous metal layers. This local quality approach concentrates the metal material precisely where required for electrical contact, minimizing the overall metal footprint and associated shading losses while ensuring adequate electrical conductivity at each contact point.
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 shading losses and manufacturing costs, while improving alignment and bonding processes through thermocompression or ultrasonic bonding techniques.
Implementation Method 1
improving alignment and bonding processes through thermocompression or ultrasonic bonding techniques
Implementation Method 2
improving alignment and bonding processes through thermocompression or ultrasonic bonding techniques
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 string of solar cells includes a plurality of back-contact solar cells, wherein each of the plurality of back-contact solar cells includes P-type and N-type doped diffusion regions. A plurality of conductive wires is disposed over a back surface of each of the plurality of solar cells, wherein each of the plurality of conductive wires is substantially parallel to the P-type and N-type doped diffusion regions of each of the plurality of solar cells. One or more of the plurality of conductive wires adjoins a pair of adjacent solar cells of the plurality of solar cells and has a relief feature between the pair of adjacent solar cells.