Photovoltaic Module Conducting Spots Shading Protection
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Solution Overview
Problem
Photovoltaic (PV) modules experience hot spots and potential damage due to shading, which existing solutions like by-pass diodes and PV-shunts are expensive or complex, and current methods do not effectively address the issue of reverse voltage and heat production in shaded cells.
Innovation Solution
Introducing non-linear conducting spots made of recrystallized silicon at precise positions within the PV cells, which act as low-conductivity paths at low voltages and high-conductivity paths at high voltages, reducing reverse voltage and heat production in shaded cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If by-pass diodes are applied to prevent hot spots, then hot spot prevention is improved, but cost increases significantly
Solution Approach 1:
The patent extracts the by-pass diode function from separate external components and integrates it directly into the PV cell structure through conducting spots formed within the semiconductor layer, eliminating the need for separate diode components and their associated connection processes
Solution Approach 2:
The patent merges the by-pass diode functionality with the PV cell structure by forming conducting spots within the semiconductor layer that serve both as electrical conductors and as integrated protection elements, combining multiple functions into a single integrated structure
2Reliability
If monolithic by-pass diodes are made for thin-film PV modules, then hot spot prevention is improved, but manufacturing process complexity increases
Solution Approach 1:
The patent removes the complex separate diode connection process and replaces it with direct formation of conducting spots within the existing semiconductor layer using simple thermal or plasma treatment processes that are already compatible with thin-film manufacturing
Solution Approach 2:
The conducting spots are formed using the PV module's own manufacturing processes (thermal or plasma treatment) without requiring additional specialized equipment or complex external processes, allowing the structure to create its own protection features during normal fabrication
3Reliability
If PV-shunts are applied to decrease reverse voltage, then voltage control is improved, but system voltage decreases and system current increases
Solution Approach 1:
The patent applies local conducting spots at specific positions within the PV cell structure rather than global parallel connections, allowing localized voltage control without affecting the overall system voltage and current characteristics
Solution Approach 2:
The conducting spots act as intermediary elements within the cell structure that provide localized shunt paths for excess voltage, mediating between the need for voltage control and maintaining overall system electrical characteristics
4Reliability
If conducting spots are introduced in the PV cell, then hot spot prevention is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent uses thermal or plasma treatment parameters to control the formation and properties of conducting spots, where parameters like temperature, treatment time, and power density can be precisely controlled to achieve consistent results without requiring extremely precise spatial positioning
Solution Approach 2:
The patent divides the conducting spots into multiple discrete locations within the PV cell, where each spot is formed at a specific position but the overall effect is distributed across multiple segments, reducing the impact of individual spot positioning variations
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 solution effectively limits the reverse voltage over shaded cells to below the break-down voltage, preventing damage and allowing for a cost-effective and simple method to address shading issues without affecting module performance under normal conditions.
Implementation Method 1
the silicon layer comprises 10 to 1000 conducting spots of recrystallized silicon per cm2
Implementation Method 2
In the shaded cells a strong local heat production can occur (hot spot) which may result to local damage of the shaded cell
Data Source
AI summary
The invention pertains to a photovoltaic (PV) module comprising a plurality of cells, each cell containing a substrate, a transparent conductor layer, a photovoltaic layer, and a back-electrode layer, wherein the photovoltaic layer comprises at least one p-i-n or n-i-p silicon layer, characterized in that said silicon layer comprises 10 to 1000 conducting spots of recrystallized silicon per cm2, each having independently a surface or 10 to 2500 μm2. The PV module can be obtained by a method wherein the p-i-n or n-i-p silicon layer is locally heated whereby said silicon is transformed at these spots, after which the silicon at these spots is allowed to solidify in a transformed dtate.