Influence of Impurities in Module Packaging on Potential-Induced Degradation [report]

P. Hacke, S. Glick, S. Johnston, R. Reedy, J. Pankow, K. Terwilliger, S. Kurtz
2012 unpublished
Chemical compounds were added into crystalline silicon cell mini modules, including in the encapsulant, interfaces, and glass, to determine their effect on potential-induced degradation (PID). Fe, either in the glass or at the glass/encapsulant interface, was found to be correlated with increased PID, but the difference in module power loss was not statistically significant compared to controls. Additions of Cu, Cr, Pb, Sn, Ag, and Na compounds to either the encapsulant or at the
more » ... nt interface did not appear correlated with PID. Lock-in thermography on bare cells affected by PID removed from the mini modules show highly localized areas of junction breakdown, and SIMS analysis indicates localized impurities as well, though a spatial relation between the two was not established. Deposition of a conductive layer on the front surface of the cell, either with semitransparent Ta or Poly 3,4-ethylenedioxythiophene (PEDOT), eliminated PID when the cells were stressed at -1000 V bias, 50°C, with the glass face grounded for 140 h.
doi:10.2172/1051893 fatcat:dl5m6xcybrdchnmcjpprgjfkxq