Example for the assignment of power loss factors: (6" cell, 2 busbars)
Cell area: 156mm*156mm=24336mm2
Busbar area: 156mm*2*4mm=1248mm2
Total active cell surface: Cell area - Busbar area=23088mm2
Defects:
Broken off crack area: 500mm2
Gridfinger defects: 220mm2
Assigned power loss factor per defect:
Crack area: 80%
Gridfinger defects: 15%
Power loss prediction:
Crack: 500mm2*0.8=400mm2
GF defect: 220mm2*0.15=33mm2
Total equivalent area: 433mm2
Result:
433mm2*100%/23088mm2=1.87% power loss
IMPORTANT: A power loss prediction scheme cannot replace laboratory tests in climatic
chambers. Power loss factors should be based on laboratory tests carried out with modules
to be evaluated in pi4_control.
• (MLP) Mono Line Prediction: Based on the theory that cracks on mono crystalline cells
extend predominantly at an angle of 45 or 135 . This prediction provides data for the
classification. Diagonal lines (joined cracks running along the same general direction) will
be listed by its angle and its separated cell area, (see fig. 1). The classification tool is used
to count mono crack lines per cell, string or module. Cross cracks can be identified and the
inactive cell surface measured.
To calculate the power loss for the MLP, only fully separated cell sections are considered at
100% loss factor, (see fig. 4).