Solar Cell Substrate with Embedded Metal Grid and Laser Sealing
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Solution Overview
Problem
Dye-sensitized solar cells (DSCs) face challenges with low conductivity of transparent oxide layers on glass substrates, leading to high internal resistances and reduced efficiency when scaling up to larger areas, which is exacerbated by the need for protective coatings and complex manufacturing processes.
Innovation Solution
The implementation of a manufacturing process that incorporates a network of highly conductive metal lines embedded beneath the transparent conductive oxide (TCO) layer on glass substrates, enhancing electron collection and reducing the need for external collecting lines, combined with a laser-assisted low-temperature glass sealing process to improve module stability and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If transparent conductive oxide (TCO) layers are applied on glass substrates to enable electron collection, then electrical conductivity is improved, but internal resistance increases and efficiency decreases when scaling to larger areas
Solution Approach 1:
The patent segments the current collection function by introducing a network of metal lines that divide and distribute electron collection across multiple pathways. This segmentation of the TCO layer into regions bounded by metal lines reduces the effective collection distance and internal resistance, allowing larger area substrates to maintain high efficiency while preserving the electrical conductivity benefits of TCO.
Solution Approach 2:
The patent implements a nested structure where metal lines are embedded within grooves in the glass substrate, and the TCO layer is deposited over these embedded lines. This nesting allows the metal lines to be integrated beneath the TCO layer, combining the high conductivity of metal with the transparent conductive properties of TCO, thereby reducing internal resistance without sacrificing electrical conductivity.
2Reliability
If metal lines are embedded in glass substrates to enhance conductivity, then internal resistance is reduced, but manufacturing complexity increases
Solution Approach 1:
The patent applies preliminary action by creating grooves in the glass substrate and embedding metal lines before depositing the TCO layer. This sequence of operations simplifies the overall manufacturing process compared to attempting to integrate metal lines after TCO deposition, as the grooves provide pre-defined pathways that guide subsequent material deposition and assembly steps.
Solution Approach 2:
The patent replaces complex post-deposition metal line integration mechanisms with a simpler mechanical groove-based embedding approach. Instead of requiring precise alignment and bonding operations to add metal lines after TCO deposition, the grooves mechanically guide and secure the metal lines in place during the deposition process, reducing manufacturing complexity.
3Ease of manufacture
If conventional sealing processes are used for glass substrates, then module assembly is simple, but long-term stability is reduced
Solution Approach 1:
The patent applies parameter changes by modifying the sealing process parameters, specifically using laser-assisted sealing that controls temperature and time parameters to achieve optimal bond strength. This laser sealing method maintains the simplicity of the sealing operation while significantly improving long-term module stability through precise control of sealing parameters, creating stronger bonds without complex additional steps.
Solution Approach 2:
The patent replaces conventional thermal or mechanical sealing methods with laser-assisted sealing. This substitution maintains operational simplicity by using a single-step laser process rather than multi-step heating or pressing operations, while achieving superior sealing quality and long-term stability through the localized, controlled energy input of the laser beam.
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 enhances the conductivity of DSCs, reduces internal resistances, and simplifies the manufacturing process, allowing for more efficient energy harvesting and improved long-term stability of solar cell modules.
Implementation Method 1
laser welding the two substrates by means the previously deposited sealing material (4)
Implementation Method 2
A laser beam is used to support the glass melting and subsequent sealing of the module
Implementation Method 3
substrates coated with a transparent conductive oxide (TCO) are improved to allow a greater electronic conductivity
Implementation Method 4
comprising the step of embedding or depositing on one or both of the mentioned substrates a conductive mesh able to carry current for the cell exterior
Data Source
AI summary
Solar cells use as substrates glass (23) coated with a transparent conductive layer (21), able to collect the electric power generated by the solar cell. This layer (21), normally a TCO, have limited conductivity, implying the use of current collector lines applied in a complex manner. The conductivity of the conductive layer (21) is increased by the application of a structure, in particular a grid, of thin conductive lines (22) inserted in grooves on the glass surface (23) or directly applied on this, followed by a TCO layer coating (21). This highly conductive grid (22) collects the electricity from the TCO layer (21) and directs it to the periphery of the cell.Both glass substrates are sealed by a process employing a precursor of glass surrounding the entire perimeter of the substrate. The glass precursor is heated to its melting point, by a laser, completely sealing the two substrates of the module.