Dr. Christian Hagendorf         

Group Leader Diagnostics Solar Cells

Fraunhofer Center  for Silicon Photovoltaics CSP

• SNEC & Intersolar Award “PIDcon” 2015

• SEMI TaskForce leader “PV Material Degradation”

• PV courses at Univ. of Appl. Sci. Merseburg 

• Group leader at CSP since 2009

• Received PhD in Physics in 2000

• More than 60 publications, 5 patents

Abstract:

During the last years several PID based module degradations have been reported for existing solar parks. This has caused intensive research activities worldwide to avoid this kind of power losses. Technology approaches to avoid PID are either focused on the system design, the module materials (especially encapsulants) or SiN optimization on the cell level. A new IEC recommendation (IEC 62804) has been developed in the last two years to test the susceptibility of full solar modules. However it has been recently shown that the root cause is an interaction of crystal defects in silicon (stacking) faults which get decorated with sodium causing shunting. In order to develop PID resistant cells a test approach is required as direct process control tool which allow the PID test on cell level. This will significantly lower cost and efforts for PID testing and will give direct response of the solar cell process itself. Different technologies like Corona testing or lifetime based tests have been developed. However, they all have the disadvantage of expensive tests equipment, test situation which differ from the real loading situations, inaccuracies and missing reliability. Fraunhofer CSP has developed an easy test approach which allows the PID test on cell level based on the IEC 62804 standard (licensed approach to Freiberg Instruments - PIDcon™).

The paper will describe the test approach, results from industrial process test and will discuss the capability of result correlation between PIDcon results on cell level and module level test according to IEC 62804.