Solar Cell Electrode Pitch Layout for Shading and Current Collection
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Solution Overview
Problem
Solar cells in existing technologies suffer from poor photoelectric conversion efficiency due to optical and electrical losses, including reflection, shadow loss, non-absorption, photo-generated carrier recombination, and contact resistance, as well as weak current collection ability.
Innovation Solution
A solar cell design with a substrate having first and second edges, a passivation layer, secondary electrodes, and main electrodes with varying pitch and connection wires that are thicker near the edges to reduce shading and resistance, optimizing current conduction paths and avoiding micro-cracking during welding and laminating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If main electrodes are arranged with equal pitch to simplify manufacturing, then manufacturing precision is improved, but current collection ability deteriorates due to sub-connection pads being located far from edges
Solution Approach 1:
The patent applies asymmetry by setting different pitch values for different electrode arrangements. Specifically, the first pitch between first main electrodes is different from the second pitch between second main electrodes, allowing optimization of current collection at different locations while maintaining manufacturability through defined asymmetric patterns
Solution Approach 2:
The patent implements local quality by positioning sub-connection pads at specific locations relative to electrode edges and chamfers. The first sub-connection pads are positioned in edge regions outside chamfers, while second sub-connection pads are positioned inside chamfer regions, allowing localized optimization of current collection based on spatial requirements
2Reliability
If connection wires are made with large cross-sectional area to reduce resistance loss, then electrical conductivity is improved, but shading area increases reducing optical efficiency
Solution Approach 1:
The patent applies local quality by varying the cross-sectional area of connection wires based on their location and function. Different portions of connection wires have different cross-sectional areas, allowing optimization of electrical conductivity where needed while minimizing shading area in light-active regions
Solution Approach 2:
The connection wires are segmented into multiple portions with different cross-sectional areas. This segmentation allows the wire to provide low resistance where current collection is critical while having reduced cross-section in regions where shading would be more detrimental to optical efficiency
3Productivity
If sub-connection pads are positioned close to edges to improve current collection, then current collection ability is improved, but micro-cracking risk increases during welding and lamination
Solution Approach 1:
The patent applies asymmetry in positioning sub-connection pads relative to chamfer locations. First sub-connection pads are positioned asymmetrically outside chamfer regions at the edges, while second sub-connection pads are positioned inside chamfer regions, optimizing current collection while avoiding high-stress areas
Solution Approach 2:
The chamfer structure serves as an intermediary element between the edge region and the main body. By positioning sub-connection pads in relation to chamfer locations, the design uses the chamfer as a mediator to achieve good current collection while maintaining structural integrity during subsequent processing
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
The design enhances current collection and reduces optical and electrical losses, improving photoelectric conversion efficiency and module total power by minimizing effective shading area and resistance, while preventing micro-cracking and enhancing carrier transmission.
Implementation Method 1
a passivation layer disposed on the substrate
Implementation Method 2
the first connection wire is in contact with a side of each of at least one of the plurality of first sub-connection pads close to the corresponding first edge
Data Source
Figure 1~2
Figure 3a~3b
Figure 4~5
AI summary
The disclosure relates to the photovoltaic field, and more specifically to a solar cell and a photovoltaic module. The solar cell includes a substrate having first edges and second edges, where the first edges include two opposite edges of the substrate along a second direction and the second edges include two opposite edges of the substrate along a first direction; two first main electrodes, where each of the two first main electrodes is close to a corresponding first edge and includes a plurality of first sub-connection pads and a first connection wire, and the first connection wire is in contact with a side of each of at least one of the plurality of first sub-connection pads close to the corresponding first edge; and at least two second main electrodes, where the at least two second main electrodes are disposed between the two first main electrodes, where each of the at least two second main electrodes includes a plurality of second sub-connection pads and a second connection wire, and the second connection wire is in contact with at least one of the plurality of second sub-connection pads, where a first pitch between a respective first main electrode and a second main electrode adjacent to the respective first main electrode is not equal to a second pitch between adjacent second main electrodes. According to the solar cell of the disclosure, it is possible to at least improve the photoelectric conversion efficiency of the solar cell.