Laser Scribing Solar Cell Backside for Tiled Modules
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Solution Overview
Problem
Conventional solar cell manufacturing using mechanical sawing is inefficient, costly, and damages cells due to heat and particulate embedding, limiting the ability to optimize solar panel characteristics.
Innovation Solution
A laser scribing process is used to create scribe regions on solar cells with precise control over depth, width, and length, allowing for efficient singulation and reducing material waste, while maintaining cell quality and enabling the creation of high-density solar panels with overlapped or tiled photovoltaic strip elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If mechanical sawing is used to cut solar cells, then cells can be divided into smaller parts, but heat is generated that damages the cell and particulate is embedded in the cell leading to degraded performance
Solution Approach 1:
The patent replaces the mechanical sawing system with a laser-based system. Instead of using physical saw blades to cut the solar cells, a laser beam is used to scribe and separate the cells. This substitution eliminates the mechanical contact that generates heat and particulate, thereby resolving the technical contradiction between productivity and harmful factors.
Solution Approach 2:
The patent changes the cutting parameter from mechanical force to optical energy. By using laser radiation with specific wavelengths and power levels, the cutting process achieves separation without the harmful thermal and particulate effects of mechanical sawing. The laser parameters (power, speed, wavelength) are optimized to achieve clean cuts while minimizing damage.
2Ease of manufacture
If standard sized cells are used, then manufacturing is simplified, but the ability to optimize characteristics of modules is limited
Solution Approach 1:
The patent applies segmentation by dividing standard-sized solar cells into smaller strips using laser scribing. This allows the cell to be segmented into multiple functional units that can be reconfigured into different module designs. The segmentation maintains manufacturing simplicity while enabling optimization of module characteristics through flexible arrangement of the strips.
Solution Approach 2:
The patent introduces dynamic flexibility by allowing the solar cell to be divided into variable configurations. Instead of fixed standard sizes, the laser scribing process can create different strip widths and arrangements, enabling adaptive module designs that optimize performance for different applications while maintaining ease of manufacture through a single base cell design.
3Productivity
If saw blades are used for cutting, then initial cutting is possible, but blades wear quickly causing quality degradation and requiring regular replacement
Solution Approach 1:
The patent replaces the mechanical saw blade with a laser beam for cutting. The laser system does not suffer from wear like mechanical blades, maintaining consistent cut quality throughout operation. This substitution resolves the contradiction between productivity and reliability by providing a non-contact cutting method that does not degrade over time.
Solution Approach 2:
The laser system is self-maintaining in terms of cut quality. Unlike mechanical blades that require replacement due to wear, the laser system maintains consistent performance without degradation. The laser parameters can be adjusted to maintain optimal cutting conditions, providing self-service capability that ensures reliable cut quality throughout the manufacturing 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
The laser scribing process enhances manufacturing efficiency, reduces costs, and improves solar panel performance by minimizing series resistance losses and maintaining cell integrity, allowing for more efficient energy production and module design flexibility.
Implementation Method 1
subjecting a portion of the backside to the laser beam at a power level ranging from about 20 Watts to about 35 Watts to cause an ablation to form a scribe region
Data Source
AI summary
In an example, the present invention provides a method of separating a photovoltaic strip from a solar cell. The method includes providing a solar cell, placing the front side of the solar cell on a platen such that the backside is facing a laser source, initiating a laser source to output a laser beam having a wavelength from 200 to 600 nanometers and a spot size of 18 to 30 microns, subjecting a portion of the backside to the laser beam at a power level ranging from about 20 Watts to about 35 Watts to cause an ablation to form a scribe region having a depth, width, and a length, the depth being from 40% to 60% of a thickness of the solar cell, the width being between 16 and 35 microns to create a plurality of scribe regions spatially disposed on the backside of the solar cell.