Solar Cell Electrode Structure for Cold-Solder-Resistant Busbars
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Solution Overview
Problem
The existing solar cell designs with busbars suffer from poor contact with solder strips, leading to cold soldering and power losses due to micro cracks, which reduces the efficiency of solar modules.
Innovation Solution
The electrode structure features busbars with two sub-busbars arranged oppositely, where first sub-portions protrude to sandwich electrode pads, allowing direct contact with a solder strip and reducing micro cracks, with a specific ratio of sub-portion distances to enhance soldering tension and avoid waste.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If traditional busbar design is used, then silver paste consumption is reduced, but contact with solder strip is poor leading to cold soldering and micro cracks
Solution Approach 1:
The busbar is segmented into two sub-busbars arranged oppositely, creating a sandwich structure that clamps the electrode pad. This segmentation allows the busbar to maintain good contact with the solder strip while reducing silver paste consumption in the finger regions.
Solution Approach 2:
The invention transitions from a traditional single-plane busbar design to a three-dimensional sandwich structure where sub-busbars are arranged in opposite directions. This dimensional change enables simultaneous optimization of contact quality and material consumption.
2Loss of energy
If busbars are designed to reduce current transmission paths, then power loss is reduced, but contact with solder strip deteriorates
Solution Approach 1:
By dividing the busbar into two sub-busbars, the design maintains short current transmission paths while the opposing arrangement creates effective clamping contact with the solder strip, eliminating the trade-off between power loss reduction and soldering quality.
Solution Approach 2:
The invention merges the functions of current conduction and mechanical clamping into a single integrated busbar structure, where both sub-busbars work together to achieve dual objectives of low power loss and high soldering reliability.
3Reliability
If sub-busbars are arranged oppositely to sandwich electrode pads, then soldering tension is improved, but device complexity increases
Solution Approach 1:
The segmentation of the busbar into two sub-busbars creates the sandwich structure that improves soldering tension. While this increases structural complexity, the segmentation allows for standardized manufacturing processes that mitigate the complexity burden.
Solution Approach 2:
The invention optimizes specific parameters such as the distance ratio between sub-busbars (l1/l2 between 1.2-2.0) to achieve optimal soldering tension. These parameter optimizations balance the improved reliability against the increased structural complexity.
Data Source
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AI summary
An electrode structure, a solar cell, and a photovoltaic module are provided. The electrode structure includes: busbars extending along a first direction and each including two sub-busbars arranged opposite to each other along a second direction intersecting with the first direction, each of the sub-busbars includes first sub-portions and second sub-portions that are spaced at intervals; fingers extending along the second direction and arranged at two sides of the busbars, the fingers are connected to the sub-busbars; and electrode pads sandwiched between the first sub-portions of the two sub-busbars and connected to the first sub-portions, the first sub-portion of at least one of the sub-busbars protrude towards a side away from the electrode pads.