IEC 60904-1:2020 pdf free download – Photovoltaic devices
1Scope
This part of lEC 60904 describes procedures for the measurement of current-voltagecharacteristics (-V curves) of photovoltaic(PV) devices in natural or simulated sunlight.Theseprocedures are applicable to a single PV solar cell, a sub-assembly of PV solar cells, or a PVmodule.They are applicable to single-junction mono-facial PV devices.For other device types,reference is made to the respective documents，in particular for multi-junction devices toIEC 60904-1-1 and for bifacial devices to lEC TS 60904-1-2.Additionally informative annexesare provided concerning area measurement of PV devices (Annex A)，PV devices withcapacitance(Annex B), measurement of dark current-voltage characteristics (dark I-V curves)(Annex C) and effects of spatial non-uniformity of irradiance (Annex D).
NOTE The methods provided in this document can also be used as guidance for taking 1-v curves of PV arrays.Foron-site measurement refer tolEC61829.
This document is applicable to non-concentrating PV devices for use in terrestrial environments,with reference to (usually but not exclusively) the global reference spectral irradiance AM1.5defined in lEC 60904-3. lt may also be applicable to PV devices for use under concentratedirradiation if the application uses direct sunlight and reference is instead made to the directreference spectral irradiance AM1.5d in lEC 60904-3.
The purposes of this document are to lay down basic requirements for the measurement of I-Vcurves of PV devices, to define procedures for different measuring techniques in use and toshow practices for minimising measurement uncertainty. lt is applicable to the measurement ofl-V curves in general.I-V measurements can have various purposes,such as calibration (i.e.traceable measurement with stated uncertainty,usually performed at standard test conditions)of a PV device under test against a reference device, performance measurement under variousconditions (e.g. for device temperature and irradiance) such as those required by IEC 60891(for determination of temperature coefficients or internal series resistance), by iEC 61853-1(power rating of PV devices) or by IEC 60904-10 (for determination of output’s lineardependence and linearity with respect to a particular test parameter). I-V measurements arealso important in industrial environments such as PV module production facilities, and for testingin the field.Further guidance on l-V measurements in production facilities is provided inIEC TR 60904-14.
The actual requirements (e.g. for the class of solar simulator) depend on the end-use.Otherstandards referring to iEC 60904-1 can stipulate specific requirements. Where thoserequirements are in conflict with this document, the specific requirements take precedence.
4.2Measurements
a) When the measurements are intended to be reported at standard test conditions (see 4.5)
the in-plane average irradiance during measurement shall be between 800 w-m-2 and1 200 W-m-2 to minimise errors arising from large corrections.
b)Temperature sensors should be located so as to detect as closely as possible the
temperature of the respective device cell junction. If a temperature gradient between thesensor and the cell junction is suspected, an appropriate contribution to the measurementuncertainty should be included.Consideration should also be given to any possible non-uniformity of temperature across either device，particularly for PV modules,where thetemperature of individual cells can vary due to their electrical characteristics, particularlywhen the module is illuminated under short-circuit conditions. The Equivalent CellTemperature(ECT) method specified in lEC 60904-5 can be useful in dealing with either atemperature gradient or temperature non-uniformity. The cooling effect from airflow (forexample due to wind during outdoor measurement or due to air conditioning of the room forindoor measurements) on the temperature sensors should be considered in the uncertaintyof the temperature measurement.
c) The active surface of the device under test shall be coplanar within ±2° with the active
surface of the reference device.
d) Voltages and currents shall be measured using independent leads from the terminals of the
device under test and keeping them as short as possible. lf the device under test is a module,a subassembly or an encapsulated solar cell， the 4-wire connection should start at theterminals or connectors. lf the device under test is a bare PV cell, the 4-wire connectionshould start at the cell bus bars.The connection method for bare cells (i.e. provided withoutconnectors) should be carefully evaluated.Differences can occur if soldered tabs are usedcompared with non-soldered methods such as bars having contact springs or conductiveplates having a large-area contact with the cell back contact. Non-soldered methods canresult in higher fill factors than are observed in the module.