Upright Photovoltaic Cell Front-Contact Layout Without Back-Side Welding
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Solution Overview
Problem
Existing photovoltaic (PV) cells with back-side contacts face challenges due to the mechanical fragility of the substrate, leading to damage and increased manufacturing costs during the welding process, especially in thin or flexible PV cells.
Innovation Solution
The development of an upright PV cell architecture with both positive and negative contacts arranged on the front side, eliminating the need for back-side welding and reducing the risk of damage during the manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If back-side contacts are used in PV cells, then the mechanical fragility of the substrate is exposed during welding, but front-side contacts with both positive and negative terminals eliminate welding damage risk
Solution Approach 1:
The patent inverts the conventional contact configuration by placing both positive and negative contacts on the front side of the PV cell rather than using back-side contacts. This inversion eliminates the need for welding to the fragile substrate back side, thereby preventing mechanical damage while maintaining manufacturability through alternative contact formation methods
Solution Approach 2:
The patent extracts the welding process from the manufacturing sequence by eliminating back-side contacts that require welding. Instead, contacts are formed through deposition processes on the front side, removing the harmful welding step that causes substrate damage
2Reliability
If thin or flexible PV cells are manufactured with back-side contacts, then substrate damage frequency increases, but front-side contacts reduce damage while maintaining performance
Solution Approach 1:
The patent applies inversion by reversing the conventional contact placement from back-side to front-side configuration. This reversal is particularly beneficial for thin and flexible PV cells where substrate fragility is pronounced, as it eliminates welding-induced mechanical stress on the substrate while preserving electrical functionality
Solution Approach 2:
The patent changes the spatial parameters of contact placement from the back side to the front side of the PV cell. This parameter change fundamentally alters the mechanical stress distribution during manufacturing, reducing damage frequency in thin and flexible cells without compromising electrical performance
3Ease of manufacture
If conventional front and back contacts are used, then welding is required which increases manufacturing costs, but front-side only contacts eliminate welding and reduce costs
Solution Approach 1:
The patent extracts the welding process from the manufacturing sequence by eliminating back-side contacts. Contacts are formed through deposition processes on the front side, removing the costly and damage-prone welding step while maintaining electrical connectivity
Solution Approach 2:
The patent substitutes the mechanical welding process with a deposition-based contact formation method. Instead of mechanically joining contacts to the substrate through welding, contacts are deposited directly onto the front side, eliminating mechanical stress and associated costs
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 approach significantly reduces the frequency of PV-cell damage and manufacturing costs, while maintaining high efficiency and performance comparable to traditional PV cells with front and back contacts.
Implementation Method 1
growing one or more epitaxial layers on a substrate, thereby forming a diffused active junction on the substrate
Implementation Method 2
depositing contact material onto the substrate-contact region, to form the first contact, and concertedly onto a mesa-contact region of the mesa, to form the second contact
Implementation Method 3
Photovoltaic (PV) cells, often referred to as 'solar cells’, convert light into electrical energy. A PV cell includes at least one band-gap material, typically a semiconductor, that generates electron-hole pairs upon absorption of light
Data Source
AI summary
A method for fabricating an upright photovoltaic cell comprises growing one or more epitaxial layers on a substrate, thereby forming a diffused active junction on the substrate and one more additional active junctions above the diffused active junction. The method further comprises selectively etching an areal region of the one or more epitaxial layers, thereby forming a mesa on the substrate and exposing a substrate-contact region parallel to the areal region at a base of the mesa. The method further comprises depositing contact material onto the substrate-contact region, to form the first contact, and concertedly onto a mesa-contact region of the mesa, to form the second contact.