Cell/ Module Characterization

While accelerated stress testing stresses and degrades a photovoltaic module, simple cell and module characterization techniques quantify the degradations and reveal where and how it fails electrically and physically. In solar reliability research, a simple drop in power output is only a macroscopic symptom. To truly mitigate degradation, researchers must pinpoint the exact electrical and physical root causes—whether that is a microscopic crack in the silicon wafer, localized cell shunting, degraded solder bonds, or poor charge carrier collection. These advanced diagnostics provide the necessary "x-ray vision" to map and understand PV wear-out mechanisms at the device level long before they lead to total module failure.

Building on decades of failure analysis and diagnostic research, our lab conducts several distinct tiers of module and cell characterization:

• Electrical Performance Diagnostics: Quantifying exact power losses and identifying specific electrical fault types (such as series resistance increases or current mismatches) using high-precision I-V tracing.
• Electro-Optical & Thermal Imaging: Utilizing Electroluminescence (EL), Infrared (IR), and Ultraviolet Fluorescence (UVF) to visually map out hidden electrical defects, hotspots, microcracks, and inactive cell regions across a full, intact module.
• Spectral Responsivity: Using Quantum Efficiency (QE) testing to measure exactly how effectively a specific region of a cell converts various wavelengths of sunlight into electrical current.
• Electrochemical Impedance: Utilizing EIS to probe the internal electrical interfaces of the module, detecting early-stage interfacial degradation modes like Potential-Induced Degradation (PID) or moisture-induced corrosion.

The lab conducts comprehensive electrical and visual diagnostics to evaluate performance and pinpoint failure mechanisms in solar cells and modules:

• I-V Tracing: State-of-the-art cell solar-simulator, alongside automated multi-module tracers and single-module curve tracers to measure performance characteristics of cells/modules, including high-capacitance samples.
• Quantum Efficiency (QE): A specialized Cell-Module QE machine capable of isolating and analyzing specific, individual points within a fully laminated module.
• Advanced Imaging: Indoor and outdoor imaging capabilities including Electroluminescence (EL), Infrared (IR), and Ultraviolet Fluorescence (UVF).
• Defect Correlation: Researchers quantify UVF and EL imaging to track degradations like encapsulant browning, cell shunting, and grid finger degradation. UVF imaging is particularly valuable for detecting how polymer additives migrate from the backside to the front of the cell during lamination and aging, revealing chemical changes missed by naked-eye inspections.
• Spectroscopy: Electrochemical Impedance Spectroscopy (EIS) for detailed material and interfacial degradation analysis.