EN IEC 62787:2021 pdf download.Concentrator photovoltaic (CPV) solar cells and cell on carrier (CoC) assemblies - Qualification
7.1 General
The optoelectronic performance characterization based on ilumination I-V curves tries to identify optoelectronic performance degradation of test samples caused by the required qualification tests. Therefore, illumination I-V curve has to be performed before and after qualification tests. The goal of the ilumination I-V curve is on the relative power degradation,not on the absolute power output. Scanning Acoustic Microscopy (SAM) is also required but only for CoCs.
In addition, electroluminescence mapping and dark I-V curve can provide diagnostic information about defects and changes within the device. Before and after qualification testing, dark I-V curve can be carried out for the voltage and current ranges of interest. Electroluminescence images are not explicitly suggested through this document, but they could be of great help when captured for each device at different current injection levels before and after some qualification tests.
7.2 Light I-V measurement
This is a compulsory characterization method. All test samples shall be measured at 25 °C,under AM1 .5D spectrum as specified in IEC 62670-1，and at an overall light intensity representative of the intended application. For the purposes of this characterization method, 1 sun equivalent of the AM1. 5D spectrum will have a total power density (irradiance) of 0,1 W/cm2,so that a light intensity of 100 W/cm2 = 1 000 suns. The parameters and measurement methods for the light I-V measurement are defined in IEC 60904-1-1:2017.
7.3.2 Procedure
If the dark I-V is used for diagnostic purpose, it should be measured during initial measurements to establish a reference for later dark I-Vs.
a) Choose a suitable power source, which could be a conventional DC power supply, as long as it will generate current up to 1,5 times the rated current point corresponding to the photocurrent at the specified maximum concentration. The current should be adjustable so that there are at least 30 separate points in the range of 10-4 to 1,5 times rated Isc at the specified maximum concentration. The interval of the points should be nearly equal-spaced with a lower pitch around Isc;
b) For CoCs, short the blocking diode by placing a jumper lead across the leads of the blocking diode, if there is one installed;
c) Connect the power source's positive lead to sample's positive lead, and the power source's negative lead to sample's negative lead;
d) Block completely the light impinging the cells;
e) Temperature shall be controlled and repetitive in order to comparing measured I-V results;
f) Apply current to the device and record current, voltage and temperature. Complete this procedure as quickly as possible to avoid significant heating of the devices during the test.EN IEC 62787 pdf download.