Thermography and electroluminescence imaging of scribing failures in Cu(In,Ga)Se₂ thin film solar modules

Abstract

Intentionally implemented scribing failures in Cu(In,Ga)Se2 modules are studied using electroluminescence (EL) and dark lock‐in thermography (DLIT). While the EL images do not allow a non‐ambiguous defect distinction, the DLIT images reveal characteristic defect patterns for each defect type. In order to explain the DLIT defect appearance, we model and simulate the scribing defects in a network simulation model. The simulations yield characteristic current flow patterns for each scribing defect type and thus aid in the understanding and interpretation of the measurements.

Defect Diagnostics of Scribing Failures and Cu-Rich Debris in Cu(In,Ga)Se<inline-formula><tex-math>$_2$ </tex-math></inline-formula> Thin-Film Solar Modules With Electroluminescence and Thermography

“…We have explained the creation of the two heat centers in Fig. 2(b) in detail with our NSM in our previous contribution [2]. Fig.…”

“…We have shown this approach for abnormalities in the Cu(In,Ga)Se 2 (CIGS) sequence layer in [1], where we have deliberately pierced single layers locally during the manufacturing of the module, in order to model imperfect layer deposition. Furthermore, we have shown this approach for the three scribing lines (P1, P2, and P3) that constitute the monolithic series connection in the CIGS module in [2].…”

“…While our two previous contributions [1], [2] focused on the description of the general defect physics, namely, the resulting abnormal current flow and voltage distribution, we want to present, in this study, how variations of defect geometry and defect position influence their appearance and detectability. We choose the electroluminescence (EL) and dark lock-in thermography (DLIT) as spatially resolved measurement techniques, which have proven to be suitable for the characterization of defects [3]- [5].…”

Automatized analysis of IR‐images of photovoltaic modules and its use for quality control of solar cells

“…We want to point out that electrical defects also may and do occur when producing inorganic solar cells. The detrimental effect of "hot spots" has been reported in a various number of publications for different solar cell types (for example for silicon [3][4][5][6][7][8][9][10], CIGS [11][12][13][14][15][16], CdTe [17][18][19] and for OPV [20][21][22][23]). In any case, an automatized recognition and analysis of the defects is a highly desirable tool.…”

Electrical Repair of Incomplete Back Contact Insulation (P1) in Cu(In,Ga)Se<inline-formula><tex-math> $_2$</tex-math></inline-formula> Photovoltaic Thin-Film Modules

“…Incomplete P1 scribing causes local short circuits between the cells. complete P1 scribing leads to severe shunting, even for small P1 line interruptions of only a few μm due to the high conductivity of the Mo layer [10].…”