Daylight PV Module Luminescence Imaging Without External Power
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Solution Overview
Problem
Existing methods for electroluminescence and photoluminescence characterization of photovoltaic modules, strings, and arrays are labor-intensive, expensive, and inefficient, particularly when performed outdoors in daylight without an external energy source.
Innovation Solution
The method involves using a device connected to a current generating photovoltaic cell to increase its voltage relative to a current sinking cell, and then taking images under equivalent and increased voltage conditions to determine damage by subtracting the images. This process can be performed in daylight without an external energy source.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If mobile solar module testing vans are used for daytime electroluminescence measurements, then measurement can be performed in daylight, but the process becomes labor intensive, expensive, and requires removing modules from racking systems
Solution Approach 1:
The system uses the photovoltaic modules themselves as the power source for electroluminescence imaging. Current-generating modules provide electrical power to current-sinking modules under test, eliminating the need for external power supplies and making the system self-sufficient. This resolves the contradiction by enabling daylight operation without requiring labor-intensive setup of external equipment.
Solution Approach 2:
The electroluminescence imaging system can operate in multiple modes: using either current-generating photovoltaic modules or current-sourcing photovoltaic modules as the power source. This multi-functionality allows the same system to adapt to different field conditions without requiring separate equipment, reducing labor and operational complexity while maintaining daylight measurement capability.
2Power
If external power supplies are used for nighttime electroluminescence measurements, then sufficient current can be injected into modules, but the process becomes labor intensive, expensive, and slow requiring crew operation
Solution Approach 1:
The system eliminates external power supplies by using the photovoltaic array's own modules as power sources. During daytime, current-generating modules provide sufficient electrical power to current-sinking modules under test, enabling high-throughput imaging without manual connection and disconnection of external equipment. This self-powered approach dramatically increases productivity while maintaining adequate current injection capability.
Solution Approach 2:
The system merges the functions of power generation and power consumption into a single integrated photovoltaic array. Multiple modules work together where some generate current and others consume it for imaging, creating a cooperative system that achieves both sufficient power delivery and high measurement throughput without external equipment.
3Ease of manufacture
If photoluminescence technique is used for failure diagnostics, then optical carrier injection can be performed, but resistive effects and cracks cannot be captured due to the different injection mechanism
Solution Approach 1:
The system changes the carrier injection parameter from purely optical (photoluminescence) to electrical (electroluminescence) by applying electrical current through the electrical connection between modules. This parameter change enables the detection of resistive effects and cracks while maintaining the field-operability advantage of the optical approach.
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 enables effortless, high-throughput electroluminescence and photoluminescence characterization, reducing labor and costs while maintaining accuracy, even in daylight conditions without the need for external energy sources.
Implementation Method 1
using a device connected to a current generating photovoltaic cell to increase its voltage relative to a current sinking cell
Implementation Method 2
Electroluminescence is an essential characterization technique for photovoltaics cells and modules
Data Source
AI summary
Photoluminescence and electroluminescence are essential characterization techniques for photovoltaics cells and modules. For electroluminescence, the main technical challenge is easily injecting current into the photovoltaic to cause luminescence. The technique described herein enables daylight electroluminescence imaging without the need for external power sources. For photoluminescence, characterization is performed on photovoltaic cells, modules, strings, and arrays in daylight and without temporary mounting of LED modulators. Instead, the modulation is performed using a permanent electronic module installed within the electric circuit on the DC side. This enables automation or triggering of modulation on demand, 100% inspection without changes in hardware configuration because the cells are never shaded and provides a path to high throughput imaging.