Hetero-Junction Solar Cell Edge Isolation Without Short Circuits
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Solution Overview
Problem
Conventional methods for edge isolation in hetero-junction solar cells often result in electrical short circuits and damage to the substrate, with existing techniques either being costly, complex, or reducing cell performance.
Innovation Solution
Forming a conductive back coating on the back layer with a distance from the edge of the semiconductor substrate, creating a merging region that prevents electrical contact between the back and front coatings, and using a mask to protect the edge during deposition, ensuring no short circuits and maintaining cell integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If laser drilling is used to structure the conductive films for edge isolation, then electrical short circuits are prevented, but damages are created to substrate regions and layers
Solution Approach 1:
An intrinsic amorphous silicon layer is introduced as an intermediary between the conductive layers and the substrate. This intermediate layer absorbs the harmful effects of the edge isolation process, preventing damage to the underlying substrate and other layers while still achieving electrical isolation at the edges
Solution Approach 2:
The intrinsic amorphous silicon layer is deposited beforehand before the conductive layers are applied. This preliminary action prepares the substrate with a protective layer that will prevent damage during subsequent processing steps, particularly during laser drilling or other edge isolation procedures
2Reliability
If the front transparent conductive film is structured to achieve edge isolation, then electrical short circuits are prevented, but cell performance decreases
Solution Approach 1:
The edge isolation is achieved by segmenting the intrinsic amorphous silicon layer at the edges rather than structuring the front transparent conductive film. This segmentation approach maintains the integrity and continuity of the conductive film across the cell surface, preserving cell performance while still achieving electrical isolation where needed
Solution Approach 2:
The intrinsic amorphous silicon layer serves as an intermediary that provides edge isolation functionality without requiring structuring of the front transparent conductive film. By placing the isolation function in this intermediate layer, the conductive film remains continuous and effective, maintaining cell performance
3Reliability
If a narrow line of coating is applied at the cell edge and then removed to create edge isolation, then electrical short circuits are prevented, but the process becomes complex and risky
Solution Approach 1:
Instead of adding a narrow line of coating and then removing it, the invention extracts or omits the conductive material from the edge regions directly through masking during deposition. This eliminates the need for the complex two-step process of adding and then removing material, simplifying the manufacturing process while achieving the same electrical isolation result
Solution Approach 2:
The edges are protected from conductive material deposition in advance using a mask with a cover region, rather than attempting to remove material after deposition. This preliminary action prevents the formation of conductive material at the edges from the start, avoiding the complexity and risks of subsequent removal steps
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 effectively prevents short circuits without damaging the solar cell, reduces costs, and maintains high cell performance by allowing more light collection and a uniform appearance.
Implementation Method 1
forming an electrically conductive anti-reflection coating on the at least one front layer, said anti-reflection coating covering the whole surface of the at least one front layer and being at least partially transparent to the light irradiating into the solar cell
Implementation Method 2
providing a doped and textured semiconductor substrate... forming an electrically conductive anti-reflection coating... being at least partially transparent to the light irradiating into the solar cell
Data Source
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AI summary
The present invention relates to a method of manufacturing a hetero-junction solar cell with edge isolation, the solar cell having a front side for an incidence of light Into the solar cell and a back side opposite to the front side. The method includes the steps of: providing a doped and textured semiconductor substrate, said semiconductor substrate having a front surface and a back surface opposite to each other and an edge surrounding the semiconductor substrate; forming at least one front layer on the front surface of the semiconductor substrate, said at least one front layer containing semiconductor atoms or molecules being arranged in amorphous and/or microcrystalline and/or oxide and/or carbide phase; forming at least one back layer on the back surface of the semiconductor substrate, said at least one back layer containing semiconductor atoms or molecules being arranged in amorphous and/or microcrystalline and/or oxide and/or carbide phase; forming an electrically conductive anti-reflection coating on the at least one front layer, said anti-reflection coating covering the whole surface of the at least one front layer and being at least partially transparent to the light irradiating into the solar cell; forming an electrically conductive back coating on the at least one back layer; and forming a front grid metallization on the anti-reflection coating. The invention further relates to an according edge isolated hetero-junction solar cell. It is the object of the present invention to provide an easy and low-cost method of manufacturing of a hetero-junction solar cell and an according solar cell, wherein short circuits between the front and the back side of the solar cell are prevented and the solar cell is not damaged by the method steps and shows good cell performance. This object is solved by a method of the above mentioned type and an according hetero-junction solar cell, wherein the conductive back coating is formed on the surface of the at least one back layer with a distance to the edge of the semiconductor substrate, leaving a merging region consisting of a margin area of the surface of the at least one back layer and the edge of the semiconductor substrate free from the conductive back coating, wherein there is no electrical contact between the conductive back coating and the conductive anti-reflection coating at all during the whole process of formation of the conductive back coating.