Method and device for producing solar cells
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Solution Overview
Problem
The existing methods for manufacturing solar cells using silicon substrates are inefficient due to the need for large floor space, quality issues caused by conveyor rollers, difficulty in controlling the electroplating process, and limited deposition rates, especially when dealing with fragile and thin substrates.
Innovation Solution
The method involves suspending silicon substrates vertically during electroplating, using a conveyor element with clamping elements to support and connect them as cathodes, and employing a narrow electrolytic bath to reduce floor space and optimize surface area for electroplating, with a flexible conductive tape and clamping elements that allow for stable and efficient transport and electroplating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If substrates are conveyed horizontally on conveyor rollers through the electrolytic bath, then the substrates can be transported through the bath, but the conveyor rollers cause screening effects that adversely affect electroplating quality and require large floor area
Solution Approach 1:
The patent transitions from horizontal substrate conveyance to vertical suspension conveyance through the electrolytic bath. Substrates are suspended vertically from an overhead conveyor system, allowing the bath to be positioned above the substrate path rather than beside it. This dimensional change eliminates the screening effect of rollers on the substrate surface and reduces the horizontal footprint of the equipment while maintaining effective electroplating coverage.
2Ease of operation
If contact rollers are used to make cathodic contact with tracks, then electrical contact can be established, but the rollers require synchronization control with blow nozzles and substrates movement, increasing process complexity
Solution Approach 1:
The patent extracts the electrical contact function from the mechanical conveyor rollers and separates it into a dedicated overhead contact system. The flexible conductive tape suspended from the overhead conveyor makes cathodic contact with the substrate tracks independently of the substrate transport mechanism. This extraction eliminates the need for synchronized control between contact rollers, blow nozzles, and substrate movement, as the overhead tape naturally follows the substrate position during vertical conveyance.
Solution Approach 2:
The patent introduces a flexible conductive tape as an intermediary element between the power supply and the substrate tracks. This tape can adapt to substrate position variations and maintain reliable electrical contact without requiring precise mechanical synchronization. The tape acts as a compliant mediator that absorbs positioning tolerances and eliminates the need for complex control systems while ensuring continuous cathodic contact during the electroplating process.
3Productivity
If substrates are conveyed horizontally, then transport through the bath is possible, but the deposition rate is limited by the conductive capacity of the substrate material requiring long dwell times
Solution Approach 1:
The vertical suspension configuration improves electrical contact between the conductive tape and substrate tracks, reducing contact resistance and enhancing the effective conductive capacity. This dimensional change allows higher current densities to be applied to the substrate, increasing the electroplating deposition rate and reducing the required dwell time in the electrolytic bath, thereby improving overall productivity.
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 reduces the required floor space, minimizes mechanical stress on substrates, and enhances the electroplating process by maintaining a clear surface area for deposition, leading to improved efficiency and reduced contamination risks.
Implementation Method 1
Said substrates are passed through an electrolytic bath in a horizontal orientation... use is made of conveyor rollers arranged one behind the other, on which the substrates are supported, and of contact rollers disposed directly above said conveyor rollers, via which cathodic contact can be made with the tracks on the upper side of the substrate
Implementation Method 2
Each contact roller is connected via an electrical switch to an electronic circuit which also comprises a rectifier and the anode
Data Source
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AI summary
The present invention provides a method for producing solar cells, comprising the steps of - providing silicon containing vitreous substrates, each provided with an electrically conductive material on at least one side thereof, - successively transporting at least a portion of each substrate through an electrolytic solution that is present in an electrolytic bath, - connecting said electrically conductive material as the cathode during the transport of the substrates through the electrolytic bath for the purpose of electrodepositing material from the electrolytic solution onto the electrically conductive material during said transport, wherein the substrates are suspended from a conveyor element during transport and extend in the transport direction. The invention further provides a device for producing solar cells.