Solar Cell Secondary Grid Line Width Variation
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Solution Overview
Problem
Existing solar cell technologies face challenges in balancing light blocking and electrical conduction due to the presence of primary and secondary grid lines, which increase manufacturing costs and reduce photoelectric conversion efficiency. The use of metal wires as substitutes for silver primary grid lines is limited by equipment constraints and poor welding processes, leading to low connection strength and efficiency issues.
Innovation Solution
A solar cell design where the secondary grid lines have a widened width at the welding position to enhance the connection strength with conductive wires, allowing for reliable welding and reduced shading area, while maintaining a narrower width elsewhere to minimize light blocking, thereby improving photoelectric conversion efficiency and reducing manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the welding strip, primary grid lines and secondary grid lines are designed as fine as possible, then light blocking is reduced and more sunlight is received, but the conductive cross section area decreases causing greater electricity loss due to increased resistivity
Solution Approach 1:
The secondary grid line is designed with different widths at different locations: a first width at the welding position and a second width at non-welding positions. This local variation allows the grid line to have sufficient conductive cross-section at welding points while maintaining minimal width elsewhere to reduce light blocking, thus resolving the contradiction between light reception and electrical conduction.
2Reliability
If the number of primary grid lines is increased, then electrical conduction is improved, but the shading area is enlarged and photoelectric conversion efficiency is reduced
Solution Approach 1:
The secondary grid line width is optimized locally: wider at welding positions to ensure good electrical connection with conductive wires, and narrower at non-welding positions to minimize shading. This allows multiple grid lines to be implemented effectively without excessive light blocking, improving electrical conduction while maintaining photoelectric conversion efficiency.
3Ease of manufacture
If metal wires are used to replace silver primary grid lines, then manufacturing cost is reduced and shading area is decreased, but equipment constraints and poor welding processes lead to low connection strength
Solution Approach 1:
The secondary grid line is designed with a wider width specifically at the welding position where conductive wires are attached. This localized width increase provides sufficient material for reliable welding of metal wires, ensuring strong connection strength while the narrower non-welding portions maintain cost-effectiveness and reduced shading.
4Illumination intensity
If the secondary grid line has a narrow width to minimize light blocking, then photoelectric conversion efficiency is improved, but the connection strength with conductive wires is insufficient
Solution Approach 1:
The secondary grid line implements variable width design with a first width at the welding position and a second width at non-welding positions. The first width is specifically increased to provide adequate connection strength for welding conductive wires, while the second width remains narrow to minimize light blocking and maintain high photoelectric conversion efficiency.
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 enhanced connection strength between conductive wires and secondary grid lines improves the solar cell's efficiency and reduces manufacturing costs, enabling mass production of solar cells with increased conductive wire density without compromising light absorption.
Implementation Method 1
the secondary grid lines having a width in a welding position with the conductive wire greater than a width thereof in a non-welding position
Implementation Method 2
Sunlight irradiates onto a cell from its front surface and is converted to electricity within the cell
Data Source
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AI summary
A solar cell unit, a solar cell array (30), a solar cell module (100) and a manufacturing method thereof are disclosed. The solar cell unit includes a cell (31) which consists of a cell substrate (311) and a secondary grid line (312) disposed on a front surface of the cell substrate (311); a conductive wire (32) intersected and welded with the secondary grid line (312), and the secondary grid line (312) having a width in a welding position with the conductive wire (32) greater than a width thereof in a non-welding position.