Micro-Extrusion Printhead With Valve Structures for Solar Gridline Printing
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Solution Overview
Problem
Conventional solar cell extrusion printing techniques face challenges in achieving clean starts and stops, handling non-rectangular substrates, and correcting misalignment, leading to segmented gridlines and potential electrical shorts.
Innovation Solution
A micro-extrusion printing system with valve structures adjacent to nozzle outlets, allowing for controlled ink flow and selective nozzle control, enabling precise printing on non-rectangular substrates and automatic misalignment correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional micro-extrusion printing is used without valve control, then the printing process is simple, but segmented gridlines occur and production yield decreases
Solution Approach 1:
The printhead is divided into multiple independently controllable nozzle groups, with each group equipped with its own valve structure. This segmentation allows selective activation of nozzle groups to prevent segmented gridlines while maintaining overall system functionality.
Solution Approach 2:
Valve structures are integrated into the printhead to enable dynamic control of ink flow at each nozzle group. The valves can be opened or closed based on real-time printing requirements, allowing clean starts and stops of ink extrusion to eliminate segmentation defects.
2Manufacturing precision
If printing continues without stopping to avoid segmented gridlines, then gridline continuity improves, but edge spacing requirements are violated and electrical shorts occur
Solution Approach 1:
The valve structures are positioned to enable preliminary control of ink flow before reaching the substrate edge. By closing valves in advance before the printhead reaches the edge region, the system prevents ink deposition that would cause electrical shorts while maintaining gridline continuity through proper timing.
Solution Approach 2:
The system uses feedback control where the position of the printhead relative to the substrate edge is monitored, and valve actuation timing is adjusted accordingly. This ensures gridlines are deposited continuously while automatically preventing edge violations that would cause electrical shorts.
3Adaptability or versatility
If the printhead is designed to handle non-rectangular substrates with selective nozzle control, then adaptability improves, but device complexity increases
Solution Approach 1:
The printhead is segmented into multiple nozzle groups with individual valve control, allowing selective activation of only the nozzles needed for the current substrate shape. This enables handling of non-rectangular substrates by activating appropriate nozzle groups while keeping others closed.
Solution Approach 2:
The valve-controlled printhead design provides universal capability to handle various substrate shapes and sizes. The same printhead structure can adapt to rectangular, circular, or irregular substrates by programmatically controlling which valve groups are active, eliminating the need for multiple specialized printheads.
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 system reduces segmented gridlines, maintains edge spacing requirements, and prevents electrical shorts, improving production yields and efficiency in solar cell manufacturing.
Implementation Method 1
the valve structure is movable between a first position in which the valve structure blocks flow of the extrusion material through the nozzle channel and a second position in which the valve structure allows flow of the extrusion material through the nozzle channel
Implementation Method 2
micro-extrusion methods were developed more recently in order to meet the demand for low cost large-area semiconductors, and include extruding a dopant bearing material (dopant ink) onto the surface of a semiconductor substrate using a micro-extrusion printhead
Data Source
AI summary
A solar cell extrusion printing system includes a printhead assembly having one or more elongated valve structures that are adjustably disposed adjacent to the outlet orifices of selected nozzle channels, and a valve control device for controlling the position of the valve structures to facilitate controllable ink flow through selected nozzle channels of the printhead assembly during the gridline printing process. The printhead assembly defines an elongated opening (e.g., a slot or hole) that that intersects (i.e., passes through) each of the selected nozzle channels, and an elongated member is movably disposed in the slot and is selectively movable between a first (opened) position, in which the valve structure extrusion material is passed by the valve structure through the nozzle channel and out of the printhead, and a closed position, in which the extrusion material is blocked by the valve structure and prevented from passing through the nozzle channel.