Production monitoring

Potential induced degradation (PID) is a serious reliability problem in PV power plants. Hence it is important to investigate its products on their PID susceptibility. The aim of the PIDcon is to enable the producers to test their products as early as possible in the production chain as well as investigate the encapsulation materials.

The PIDcon allows routine quality control of standard production cells, test of new processes, material or layer variations and qualification for various module steps. Note that the PID that is considered here is the shunting of the solar cells due to high voltage stress induced leakage currents (PID-s).

The construction of the PIDcon is practical identical to the IEC standard (fig.1) .The sample stack (solar cell, EVA foil and glass) is imitating a solar modul. With this test method it is possible to test the solar cell and the encapsulation material. Figure 2 shows a typical PIDcon measurement of a PID prone solar cell.

The PIDcon has the following advantages compared to conventional PID tests on modules:

• No climate chamber necessary

• Measurement early in the production chain

• Designed for research work as wells as routine production quality control

• Short test duration, typically between 4 and 8 hours

• Measurement and recording of shunt resistance and deduction of estimated power loss