One-Dimensional Solar Cell Metallization for Busbar-Free Current Collection
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Solution Overview
Problem
Current solar cell metallization techniques suffer from photocurrent collection losses due to busbars and pads, which compromise efficiency and are not compatible with next-generation metal bonding methods, and introduce topology issues that hinder uniform bonding pressure and compatibility with high-temperature processes.
Innovation Solution
Implementing a one-dimensional finger pattern for emitter formation and metallization, which eliminates the need for busbars and pads by using a stationary mask/travelling wafer patterning scheme based on ion implantation, and utilizing a 'busless and padless' on-cell metallization pattern to reduce photocurrent collection losses and simplify processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If traditional busbars and pads are used for metallization, then electrical current collection is achieved, but photocurrent collection losses occur and efficiency is compromised
Solution Approach 1:
The patent extracts and eliminates the traditional busbars and pads from the solar cell metallization structure. By removing these components that cause photocurrent collection losses, the invention achieves a busless and padless design that directly reduces energy loss while maintaining current collection functionality through alternative one-dimensional metallization patterns.
Solution Approach 2:
The patent segments the continuous metallization into discrete one-dimensional patterns such as interdigitated back contacts or front surface fingers. This segmentation eliminates the need for large-area busbars and pads, reducing photocurrent losses while organizing the metallization into efficient current collection pathways that maintain electrical functionality.
2Reliability
If conventional metallization patterns are used, then current collection is achieved, but topology issues hinder uniform bonding pressure and compatibility with high-temperature processes
Solution Approach 1:
The patent changes the geometric parameters of the metallization from traditional two-dimensional busbar/pad configurations to one-dimensional linear patterns. This parameter change creates more uniform surface topology that enables consistent bonding pressure distribution during interconnection processes and improves compatibility with high-temperature manufacturing steps while maintaining current collection efficiency.
3Productivity
If busbars and pads are implemented, then electrical connection is established, but efficiency and cost-effectiveness are reduced
Solution Approach 1:
The patent converts the traditional approach of using large metal areas (busbars and pads) which cause shading and photocurrent losses into a beneficial one-dimensional patterned design. This transformation turns the potential harm of metal coverage into a benefit by optimizing the metal distribution to minimize shading while maximizing current collection, thereby improving both efficiency and manufacturing cost-effectiveness.
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 conversion efficiency, reduces costs, and improves reliability by minimizing photocurrent losses and simplifying the fabrication process, while being compatible with advanced metal bonding methods and high-temperature processes.
Implementation Method 1
a stationary mask/travelling wafer patterning scheme based on ion implantation
Data Source
AI summary
Approaches for fabricating one-dimensional metallization for solar cells, and the resulting solar cells, are described. In an example, a solar cell includes a substrate having a back surface and an opposing light-receiving surface. A plurality of alternating N-type and P-type semiconductor regions is disposed in or above the back surface of the substrate and parallel along a first direction to form a one-dimensional layout of emitter regions for the solar cell. A conductive contact structure is disposed on the plurality of alternating N-type and P-type semiconductor regions. The conductive contact structure includes a plurality of metal lines corresponding to the plurality of alternating N-type and P-type semiconductor regions. The plurality of metal lines is parallel along the first direction to form a one-dimensional layout of a metallization layer for the solar cell.