Back-Contact Solar Cell Electrode Structure for Parallel Gate Uniformity
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Solution Overview
Problem
Existing back-contact solar cells experience reduced assembly power due to uneven black strips and blocks during electroluminescence (EL) testing, caused by the disconnection of fine gates leading to independent cell areas with mismatched electrical performance.
Innovation Solution
The electrode structure of the back-contact solar cell includes alternately arranged first and second polar regions with spaced first and second secondary gate electrodes, connected by first and second primary gate electrodes, and interconnected by first and second connection gate electrodes that run through primary gate electrodes to form parallel connections, ensuring uniform current density and electrical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If fine gates are disconnected at primary gate electrodes to simplify electrode structure, then device complexity is reduced, but uniformity of electrical performance deteriorates causing uneven black bars in EL test
Solution Approach 1:
The electrode structure is segmented into primary gate electrodes and secondary fine gate electrodes with distinct functions. Primary gates provide main current collection paths while secondary fine gates fill the spaces between them, creating a hierarchical segmentation that maintains both structural simplicity and electrical uniformity across the solar cell surface.
Solution Approach 2:
Different regions of the electrode structure are assigned different qualities: primary gate electrodes provide robust current collection in high-current-density areas, while secondary fine gates provide additional collection paths in interstitial regions. This local differentiation ensures uniform electrical performance without requiring complete interconnection of all electrodes.
2Ease of manufacture
If independent cell areas are created by gate disconnection to simplify manufacturing, then ease of manufacture is improved, but assembly power is reduced due to mismatch
Solution Approach 1:
The solar cell is divided into multiple independent or semi-independent cell areas by the disconnection of fine gates at primary gate electrodes. This segmentation simplifies manufacturing and allows for modular assembly, while the overall array configuration maintains power through proper matching of series-connected cells.
Solution Approach 2:
The electrode structure transitions from a two-dimensional planar pattern to a three-dimensional hierarchical arrangement with primary gates forming a coarse grid and secondary fine gates forming a fine mesh between them. This dimensional addition provides multiple current collection paths without increasing manufacturing complexity.
3Loss of substance
If thin gate design is used to reduce material consumption, then loss of substance is reduced, but electrical performance uniformity deteriorates
Solution Approach 1:
The gate system is segmented into primary gates with larger cross-sections for main current collection and secondary fine gates with smaller cross-sections for supplementary collection. This segmentation allows thin gate design to reduce overall material consumption while maintaining electrical performance through the distributed network of collection paths.
Solution Approach 2:
Different gate regions have different local qualities: primary gates have larger dimensions and higher material content for robust current collection, while secondary fine gates have smaller dimensions and lower material content for filling interstitial spaces. This local quality differentiation optimizes material usage while ensuring uniform electrical performance across the entire solar cell surface.
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 design results in a more uniform electrical performance across the solar cell, reducing mismatch and increasing assembly power by connecting independent areas into an integral whole, improving EL test images and overall cell efficiency.
Implementation Method 1
a plurality of first secondary gate electrodes and a plurality of second secondary gate electrodes, which are alternately spaced, wherein the first secondary gate electrode is used to collect the current in the first polar region, and the second secondary gate electrode is used to collect the current in the second polar region
Data Source
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AI summary
The present application applies to the field of solar cell technology and provides an electrode structure of a back-contact solar cell, a cell and its assembly and photovoltaic system; a plurality of the first secondary gate electrodes of the electrode structure include a first collection gate electrode and a first connection gate electrode; the first collection gate electrode is connected to the first primary gate electrode and disconnected at the second primary gate electrode, the first connection gate electrode running through the second primary gate electrode between two adjacent first primary gate electrodes connects the two adjacent first primary gate electrodes, that is, the first connection gate electrode running through the second primary gate electrode connects the adjacent first primary gate electrodes, so that all first primary gate electrodes are connected in parallel as an integral whole with a more uniform electrical performance. The welded back-contact solar cell can become an integral whole with uniform electrical performance and, when the assembly is EL tested, improve the blackened EL strip and block in the back-contact solar cell, effectively avoid the mismatch and increase the power of the assembly.