Shunt Detection in Amorphous Silicon Modules by Current/voltage-measurements

This work presents a novel method to determine the parallel resistance of individual solar cells in an amorphous silicon based photovoltaic module. The method does not require accessing to the contacts of every cell. Therefore, it is suitable for measurements on encapsulated modules without disassembling and possibly damaging the module. The used setup measures only the current/voltage characteristics of the module. The determination of the parallel resistance exploits the dependence of the photoconductivity of intrinsic amorphous silicon on the illumination intensity. The experiments, in agreement with the simulation, show that shunts which are independent of the illumination, e.g. the interconnection shunts due to laser scribing, are the limiting factor for the operation of the proposed setup.