Solar Cell Reverse Breakdown Voltage Testing for Hot Spot Prevention
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Solution Overview
Problem
Solar cell modules experience power loss and risk of damage due to partial shading, which is exacerbated by the use of standard bypass diodes that increase manufacturing complexity and costs, and existing methods to mitigate this focus on increasing breakdown voltage rather than optimizing solar cell selection.
Innovation Solution
Selecting solar cells with reduced breakdown voltage that conduct under reverse bias before standard bypass diodes activate, allowing for a flat distribution of current and avoiding hot spots, and implementing a quality testing method that includes performance, heat build-up, and breakdown tests to identify suitable cells for module construction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If standard bypass diodes are used to protect against partial shading, then module reliability is improved, but device complexity and manufacturing costs increase
Solution Approach 1:
The invention extracts and eliminates the bypass diode component from the module design by selecting solar cells with inherently low reverse breakdown voltage that automatically conduct under reverse bias conditions, thereby protecting the module from hot spots without requiring additional protective components
Solution Approach 2:
The solar cell itself provides the protective function previously requiring separate bypass diodes by utilizing its intrinsic low reverse breakdown voltage characteristic to conduct under reverse bias, making the cell self-protecting against partial shading damage
2Object-affected harmful factors
If bypass diodes are installed to prevent hot spots, then module safety is improved, but production costs increase
Solution Approach 1:
The invention removes the bypass diode component and its associated manufacturing, installation, and quality control processes by relying on the selected solar cells' inherent low reverse breakdown voltage to provide hot spot protection
Solution Approach 2:
The invention uses standard solar cells without expensive additional protective components, relying on the cells' natural electrical characteristics to provide protection, thereby reducing material and manufacturing costs
3Loss of energy
If solar cells with reduced breakdown voltage are selected, then power loss during partial shading is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The invention changes the electrical parameter selection criterion from conventional high breakdown voltage to low reverse breakdown voltage, enabling the selection of solar cells that naturally conduct under reverse bias and prevent hot spots while maintaining standard manufacturing tolerances
Solution Approach 2:
The invention performs preliminary selection of solar cells based on low reverse breakdown voltage characteristic during the manufacturing process, ensuring that only suitable cells are assembled into modules before deployment, thereby preventing future hot spot issues
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 power loss during partial shading, avoids hot spots, and simplifies module design by potentially eliminating the need for bypass diodes, thereby decreasing production costs and increasing module efficiency.
Implementation Method 1
A photovoltaic solar cell is a flat semiconductor component in which charge carrier pairs are generated by means of incident electromagnetic radiation and then separated, so that a potential is created between at least two metallic contacting structures of the solar cell and electrical power is tapped from the solar cell
Implementation Method 2
the voltage applied to the shaded solar cells can be negative and electrical energy can be consumed in the solar cell (essentially by converting electrical energy into heat). The conversion of electrical energy into heat in the reverse-biased solar cells can damage the module
Data Source
AI summary
The invention relates to a method for testing the quality of a photovoltaic solar cell, comprising the method steps of: carrying out a power test in a method step a by applying light to the solar cell and testing, according to a test criterion A, whether at least a predefined electrical minimum power P Min can be tapped off and carrying out a heat generation test in a method step b by applying a predefined heat generation voltage V HE to the solar cell in the reverse direction, or applying voltage to the solar cell in the reverse direction in such a manner that a predefined heat generation current I HE flows, and testing, according to a test criterion B, whether the solar cell surface does not exceed a predefined limit temperature T GR . The important factor is that a breakdown test is additionally carried out in a method step c by applying a predefined breakdown voltage V DB to the solar cell in the reverse direction and testing, according to a test criterion C, whether at least a current greater than or equal to a predefined minimum breakdown current I DB flows when the predefined breakdown voltage is applied. The invention also relates to a use of a photovoltaic solar cell, to a solar cell module and to a method for producing a photovoltaic solar cell.