Solar Cell Electrode Layout with Wire Leads for Lower Shading Loss
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Solution Overview
Problem
Solar cell panels face challenges in maximizing output due to light loss and carrier movement resistance, as wide ribbons cause shading and increasing ribbons lead to output reduction.
Innovation Solution
The design incorporates a solar cell with a semiconductor substrate having intersecting axes, featuring finger lines parallel to the long axis and bus bars with pad portions along the short axis, and uses leads with a wire shape and reduced pitch to minimize light loss and carrier movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a ribbon having a large width of about 1.5 mm is used to connect solar cells, then the number of ribbons can be reduced, but light loss occurs due to the large width of the ribbon causing shading
Solution Approach 1:
The patent divides the single wide ribbon connection into multiple narrower bus bar structures with finger lines. Instead of using one wide ribbon of 1.5 mm width, the invention segments the electrical connection into multiple bus bars (e.g., 3-5 bus bars) with narrower individual widths, reducing the total shaded area while maintaining electrical connectivity. This segmentation allows light to pass through more areas of the solar cell surface.
Solution Approach 2:
The invention transitions from a simple wide ribbon configuration to a multi-dimensional bus bar structure with finger lines extending in multiple directions. The bus bars are arranged with specific spacing and orientation (parallel to short axis) while finger lines extend parallel to the long axis, creating a distributed network that reduces shading in any single dimension while maintaining comprehensive electrical collection.
2Reliability
If the number of ribbons is increased to reduce carrier movement distance and lower resistance, then output is largely lowered due to shading loss
Solution Approach 1:
The patent applies different structural characteristics to different parts of the solar cell. Bus bars are positioned at specific locations (with pad portions at ends) to optimize local electrical collection, while finger lines provide localized connections between bus bars. This local optimization allows carrier collection points to be distributed throughout the cell area, reducing movement distances without requiring excessive numbers of connection elements that would cause shading.
Solution Approach 2:
The invention changes key parameters of the connection structure: bus bar width is reduced from conventional dimensions to narrower profiles, spacing between bus bars is optimized to balance carrier collection with light transmission, and the arrangement orientation is specifically set (bus bars parallel to short axis). These parameter changes enable efficient carrier collection with minimized shading impact on overall output.
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 configuration enhances the efficiency and output of solar cell panels by reducing light loss through diffused reflection and minimizing carrier movement paths, while maintaining strong attachment properties.
Implementation Method 1
the light loss can be minimized due to diffused reflection or the like by using the lead having the wire shape
Data Source
AI summary
Disclosed is a solar cell panel including: a semiconductor substrate having a long axis and a short axis that intersect; a first conductivity type region formed on one surface of the semiconductor substrate; a second conductivity type region formed on the other surface of the semiconductor substrate; a first electrode electrically connected to the first conductivity type region; and a second electrode electrically connected to the second conductivity type region. The first electrode includes: a plurality of finger lines positioned in a first direction parallel to the long axis and being parallel to each other; and a plurality of bus bars including a plurality of pad portions positioned in a second direction parallel to the short axis. The plurality of pad portions include a first outer pad and a second outer pad located on opposite ends of the plurality of bus bars in the second direction, respectively.