Back Contact Cell Protrusion Layout to Prevent Stacking Scratches
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Solution Overview
Problem
The front surface of back contact cells is prone to scratching during stacking due to contact with the back surface of another cell.
Innovation Solution
Incorporating transparent protrusions on the front surface of the back contact cell substrate with a thickness of 28 µm-98 µm and a coverage area ratio of 1%-4%, which creates a gap between stacked cells to prevent scratching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If back contact cells are stacked in a stacking manner for transport or storage, then transport efficiency and storage density are improved, but the front surface of the back contact cell is easily scratched by the back surface of another cell
Solution Approach 1:
The patent introduces an intermediate protective structure (the transparent protrusion with specific thickness and coverage area) between the front surface of one cell and the back surface of the stacked cell. This intermediate structure prevents direct contact between the surfaces that would cause scratching, while still allowing the stacking configuration to maintain transport efficiency.
Solution Approach 2:
The patent addresses the surface scratching problem by moving the protection mechanism from the surface plane to the vertical dimension. The transparent protrusion extends in the thickness direction (28-98 μm) to create a gap between stacked cells, transforming a 2D surface protection problem into a 3D spatial solution that maintains stacking capability.
2Reliability
If transparent protrusions with larger coverage area are added to prevent scratching, then protection effectiveness is improved, but light transmission and manufacturing cost are deteriorated
Solution Approach 1:
The patent optimizes the protection effectiveness while maintaining light transmission by carefully controlling critical parameters: the thickness of the transparent protrusion (28-98 μm) and its coverage area ratio (1%-4%). These parameter ranges provide sufficient mechanical protection against scratching while minimizing the obstruction of light paths to the underlying cell surfaces.
Solution Approach 2:
Rather than making the entire front surface protective or using full-coverage coatings, the patent applies transparent protrusions only in specific locations and at specific coverage ratios (1%-4%). This localized approach provides protection where most needed while preserving light transmission in the majority of the surface area.
3Reliability
If transparent protrusions with larger thickness are used to prevent scratching, then protection effectiveness is improved, but material consumption and manufacturing cost are increased
Solution Approach 1:
The patent determines the optimal thickness range (28-98 μm) for the transparent protrusions to achieve sufficient protection against scratching. This parameter optimization ensures that the protrusions are thick enough to prevent surface damage during stacking, yet thin enough to minimize material consumption and manufacturing costs.
Solution Approach 2:
Instead of using thick, material-intensive protective layers or coatings, the patent employs thin transparent protrusions that replicate the protective function with minimal material. The protrusions serve as simplified copies of traditional protective structures, achieving the same protection goal with reduced material usage.
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
Prevents scratching of the front surface of back contact cells while maintaining effective light transmission and reducing material waste and costs.
Implementation Method 1
since each transparent protrusion, which is disposed on the front surface of the substrate, has the thickness of 28 μm-98 μm, and the total coverage area of the at least one transparent protrusion having the ratio of 1 %-4% with respect to the total area of the front surface, when another cell is stacked on the front surface of the back contact cell, there will be a gap between the two cells, so as to prevent the cell stacked on the front surface of the back contact cell from scratching the front surface of the back contact cell
Implementation Method 2
By virtue of a photovoltaic effect of a semiconductor p-n junction, sunlight can be converted into electric energy
Data Source
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AI summary
There are a back contact cell, a cell assembly, and a photovoltaic system. The back contact cell includes a substrate and at least one transparent protrusion. Two kinds of fingers distributed in a staggered manner are formed on a back surface of the substrate, the at least one transparent protrusion is provided on a front surface of the substrate, a thickness of each transparent protrusion is 28 µm-98 µm, and a ratio of a total coverage area of the at least one transparent protrusion on the front surface to a total area of the front surface is 1%-4%. In this way, since each transparent protrusion, which is disposed on the front surface of the substrate, has the thickness of 28 µm-98 µm, and the total coverage area of the at least one transparent protrusion having the ratio of 1 %-4% with respect to the total area of the front surface, when another cell is stacked on the front surface of the back contact cell, there will be a gap between the two cells, so as to prevent the cell stacked on the front surface of the back contact cell from scratching the front surface of the back contact cell, thereby facilitating improvement of the quality of the back contact cell.