The Effect of Microcrack Length in Silicon Cells on the Potential Induced Degradation Behavior

Abstract

The presence of microcracks may lead to loss in the module output power and safety hazard of the module. This paper investigated whether the existed microscopic microcracks in cells will facilitate the PID behavior. Cells with different degrees of microcracks were fabricated into small modules to undergo the simulated PID test. The I-V performance and EL images of the modules were characterized before and after the PID test. The obtained results demonstrate that with the increase in the microcracked area or length, the modules would show a more serious PID behavior. The mechanism of this microcrack length-related degradation under high negative bias was proposed.

Review of Potential‐Induced Degradation in Bifacial Photovoltaic Modules

“…Various nondestructive techniques enable the detection of cell micro‐cracks [ 135 ] and the larger the width and depth of the micro‐crack, the stronger the PID‐s effect. [ 36,136 ]…”

“…Various nondestructive techniques enable the detection of cell micro-cracks [135] and the larger the width and depth of the micro-crack, the stronger the PID-s effect. [36,136] On the rear side of p-PERC modules, PID-p has been reported due to the accumulation of positive charges on the dielectric layers, increasing the effective SRV of minority carrier electrons. PID-p indicators are the following: [7,42,44,45,50,63] 1) P max loss mainly due to I sc drop and increase of the first diode saturation current (J 01 ) and first diode ideality factor (n 1 ).…”

Review of technology specific degradation in crystalline silicon, cadmium telluride, copper indium gallium selenide, dye sensitised, organic and perovskite solar cells in photovoltaic modules: Understanding how reliability improvements in mature technologies can enhance emerging technologies

“…[16][17][18] Microcracks may form in several stages, namely, during (1) ingot cutting, (2) production of cell and module, (3) transportation and installation and (4) operation of PV module due to environmental factors such as temperature cycles, wind, snow and hail. 15,19,20 Cracks interrupt the electrical conductivity in cell regions, which leads to reduction in the short-circuit current and the increase of the series resistance, resulting in output power reduction of PV modules 21,22 and can also increase PID. 23 The position, length and orientation of microcracks influence this power reduction.…”

PV Defects Identification through a Synergistic Set of Non-Destructive Testing (NDT) Techniques

“…NDT tools such as I–V curve analysis, electroluminescence (EL), IR thermography, lock-in thermography, photoluminescence (PL), UV fluorescence (UVF), digital-image processing, and Raman spectroscopy were used for the identification of internal and external degradation factors and defects [ 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 ]. In the EL phenomenon, when current is fed into a module under positive-bias voltage V, photons of λ = 1150 nm are emitted in Si-based cells.…”