Laser-Structured Solar Metal Grids for High Aspect Ratio Lines
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Solution Overview
Problem
Existing methods for depositing metal grid lines on solar cells, such as ALD, screen printing, and inkjet printing, face challenges including low throughput, high cost, material waste, and limitations in grid line width and aspect ratio, which affect the efficiency and production efficiency of solar cells.
Innovation Solution
A method for optimizing the aspect ratio of a metal grid based on surface modification, involving the use of laser processing to form protrusion structures on the front electrode, which confine the applied ink or paste between the protrusions, thereby controlling the width and thickness of the metal grid lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the width of metal lines is reduced to decrease shading area, then the series resistance increases due to reduced cross-sectional area
Solution Approach 1:
The invention transitions from controlling only the horizontal width of metal lines to utilizing the vertical dimension by forming protrusion structures. The metal lines are deposited with increased thickness and three-dimensional height, compensating for reduced width through enhanced cross-sectional area in the vertical direction, thereby maintaining conductivity while reducing shading.
Solution Approach 2:
The invention changes the geometric parameters of metal lines from two-dimensional flat structures to three-dimensional protrusion structures with optimized width, thickness, and height. By adjusting these parameters, the aspect ratio is optimized to achieve both reduced shading area and maintained series resistance performance.
2Reliability
If the thickness of metal lines is increased to reduce series resistance, then the shading area increases due to larger cross-sectional area
Solution Approach 1:
The invention utilizes the vertical dimension by creating protrusion structures that extend upward from the front electrode surface. This allows thickness increase for conductivity improvement without proportional increase in horizontal shading area, as the additional material is positioned in the vertical dimension rather than expanding the horizontal footprint.
3Productivity
If conventional deposition methods are used without surface modification, then the alignment and deposition accuracy of metal grid lines deteriorates
Solution Approach 1:
The invention performs preliminary surface modification by forming protrusion structures before metal line deposition. These pre-formed protrusions serve as physical guides and confinement structures that automatically align and confine the deposited metal material, ensuring high deposition accuracy and proper alignment without requiring additional control mechanisms during the deposition process.
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 method allows for the application of metal grid lines with a minimum width and sufficient thickness, reducing shading and ensuring low series resistance, thereby improving the power conversion efficiency of solar cells while maintaining high production throughput.
Implementation Method 1
providing laser process on the front electrode; and forming protrusion structures on the top of the front electrode by laser induction
Data Source
AI summary
A method for optimizing the aspect ratio of a metal grid based on surface modification includes: obtaining a photovoltaic module including a front electrode; providing a laser process on the front electrode; and forming protrusion structures on the top of the front electrode by laser induction, at least two rows of protrusion structure groups forming a confining space, so that the width of liquid applied is confined within the spacing between the two adjacent protrusion structure groups and the thickness of the liquid applied is confined within the height of the formed protruding. Since the upwardly shaped protrusion structures, which may be irregular structures, are formed by laser induction on the top of the front electrode composed of a material of the front electrode, the ink and/or paste applied are confined between two or more lines.