Solar Cell Module PID Suppression via Conductor Potential Control
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Solution Overview
Problem
The photovoltaic generation system faces significant degradation due to Potential Induced Degradation (PID) caused by potential differences between solar cell modules, leading to sodium ions migrating and affecting the electric field and electrodes, which is difficult to completely prevent without increasing manufacturing costs.
Innovation Solution
A photovoltaic generation system with a first conductive wire connected to conductor parts insulated from solar cells and a constant voltage power supply, which attracts impurity ions from the glass seal to the conductor parts, reducing degradation and manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If solar cell modules are connected in series to increase voltage, then power output capability is improved, but potential difference between modules increases causing PID degradation
Solution Approach 1:
The patent applies equipotentiality by connecting conductor parts (metal frames) of all solar cell modules to a common potential through earth wires and grounding electrodes. This equalizes the potential across all modules, preventing potential differences that would otherwise cause PID degradation in series-connected high-voltage systems.
2Object-affected harmful factors
If conventional grounding method is used to prevent electrical shock, then safety is improved, but large potential difference causes sodium ion migration and PID
Solution Approach 1:
The patent equalizes potential across all modules by connecting metal frames to a common ground potential, eliminating the large potential differences (±100V to ±500V) that drive sodium ion migration while maintaining electrical shock protection.
Solution Approach 2:
The patent converts the harmful effect of potential differences into a beneficial control mechanism by intentionally applying small negative potentials (-10V to -100V) to conductor parts. This controlled potential reversal prevents sodium ion migration toward solar cells while maintaining safety, transforming the original harmful potential difference problem into a controllable protective mechanism.
3Reliability
If ionomer or polyolefin seal material is used to stop sodium ion movability, then PID is suppressed, but manufacturing cost increases
Solution Approach 1:
Instead of using expensive ionomer or polyolefin seal materials to block sodium ions, the patent applies a controlled negative potential to conductor parts, which actively repels sodium ions away from solar cells. This converts the passive material-based solution into an active electrical control solution, achieving PID suppression with conventional EVA seal material at lower cost.
Solution Approach 2:
The patent changes the electrical parameter (potential) of conductor parts from 0V to a negative potential range (-10V to -100V), which fundamentally alters the behavior of sodium ions in the seal material and glass, causing them to migrate away from solar cells without requiring expensive material substitutions.
4Reliability
If potassium is substituted for sodium in glass through chemical processing, then sodium ion movability is limited and PID is reduced, but manufacturing cost increases
Solution Approach 1:
Instead of modifying the chemical composition of glass through costly potassium substitution, the patent changes the electrical parameter (potential) of conductor parts to negative values, which physically repels sodium ions away from solar cells. This electrical parameter change achieves the same protective effect as chemical modification without the associated manufacturing costs.
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 configuration effectively suppresses solar cell module degradation due to PID while maintaining cost-effectiveness by attracting impurity ions and stabilizing the potential difference, thereby improving the system's performance and longevity.
Implementation Method 1
it is considered that this disorders an electric field of pn junction of the solar cell or corrodes the electrode and deteriorates solar cell characteristics
Implementation Method 2
supplying a potential to the conductor parts by the constant voltage power supply, it is possible to attract impurity ions included in glass for seal of the solar cell module from the solar cell side to the conductor parts side
Data Source
AI summary
A photovoltaic generation system includes: a solar cell array formed with one or more solar cell modules; and a power conditioner, wherein each of the solar cell modules includes one or more solar cells, the photovoltaic generation system further has a first conductive wire connected to a conductor parts which is provided at each of the solar cell modules and which is insulated from the solar cells, and a constant voltage power supply whose one end is connected to the first conductive wire, and a potential is supplied to the conductor parts by the constant voltage power supply. As a result, the photovoltaic generation system which can suppress degradation of solar cell characteristics due to PID while suppressing increase in manufacturing cost of the solar cell module is provided.