Research On Defects Of The Crystalline Silicon Solar Cell

This subject is the study of defects in crystalline silicon solar cells to avoid cellswith leakage defects be abandoned and increase the defect rate of the PV modules. Thiscan significant cost savings for the enterprise, improve the quality of components andrestore a bad reputation by the quality of the door sometimes.The research projects have used physical methods with model simulation, thecontrol variable method, the experimental hypothesis method, equivalent substitutionand comprehensive analysis. According to the single diode model of the solar, it canequivalent the leakage of the solar to “bypass”, equal to its parallel resistanceapproximate, and Use MATLAB to simulate the impact of the parallel resistance to itsvolt-ampere characteristic of the cell. Using of a comprehensive analysis to analysis theresult of detection the leakage of solar cell, Distinguish the type of leakage and thereasons for the formation. Study the morphology of the laser groove used the controlvariable method. For example, fixed the Q-frequency and the size of the pump currentto study the relationship between the marking speed and groove morphology. Usingexperimental comparison method to study the Laser grooved insulation and depth of theeffect of leakage repair. Using the Substitution with equivalent to study the PID effect ofPV modules. Replace the PID effect as capacitance effects to solve the PID effect of themodules.Research on the subject, draw the following achievements:(1) Junction solar cell output performance analog bypass using MATLAB, thesimulation results with the components of the PID effect is consistent with thedescription of the PID effect causes the PV modules to produce leakage.(2) Leakage detection system, based on non-destructive thermal infrared detectiontechnology to build advanced320x240pixel uncooled focal plane micro heat detectorcan detect the spectral range of7.5~14μ, and thermal sensitivity better than0.08°C.50HZ real-time imaging can be observed that the continuous high-resolution infraredthermography.(3) By means of optical microscopy, scanning electron microscopy (SEM) and energydispersive spectroscopy (EDS), through the detection of200cells containing leakagedefects, found that the type of leakage mainly concentrated in the lobes, the contamination of the aluminum particles and thin gate burn.(4) Under the same conditions of the laser parameters, the two grooves of theleakage area of the cells repair better than a groove, indicating that the laser a groovewill make the tank of residual silicon and metal particles, reducing the grooveinsulation.(5) In order to completely isolate out the contact leakage location in and around thePN junction, the depth of the groove needs more than30um.(6)According to the principle of capacitive effect to explain the PID effect and theintroduction of low dielectric constant of ETFE material transparent front panel insteadof the soda-lime glass for the development of new anti-component of the PID effect,completely through the PID effect simulation tests.Leakage detection system, the subject developed the theory of laser grooving, laserengraved with the second slot instead of water guide groove and the anti-PID effect PVmodules, can be applied to industrial production.