ASTM E1036-15(2019)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: E1036 − 15 (Reapproved 2019) An American National Standard
Standard Test Methods for
Electrical Performance of Nonconcentrator Terrestrial
Photovoltaic Modules and Arrays Using Reference Cells
This standard is issued under the fixed designation E1036; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2. Referenced Documents
1.1 These test methods cover the electrical performance of 2.1 ASTM Standards:
photovoltaic modules and arrays under natural or simulated E691Practice for Conducting an Interlaboratory Study to
sunlight using a calibrated reference cell. Determine the Precision of a Test Method
1.1.1 These test methods allow a reference module to be E772Terminology of Solar Energy Conversion
used instead of a reference cell provided the reference module E927Classification for Solar Simulators for Electrical Per-
has been calibrated using these test methods against a cali- formance Testing of Photovoltaic Devices
brated reference cell. E941Test Method for Calibration of Reference Pyranom-
etersWithAxisTiltedbytheShadingMethod(Withdrawn
1.2 Measurements under a variety of conditions are al-
2005)
lowed; results are reported under a select set of reporting
E948Test Method for Electrical Performance of Photovol-
conditions (RC) to facilitate comparison of results.
taic Cells Using Reference Cells Under Simulated Sun-
1.3 These test methods apply only to nonconcentrator ter-
light
restrial modules and arrays.
E973Test Method for Determination of the Spectral Mis-
1.4 The performance parameters determined by these test match Parameter Between a Photovoltaic Device and a
Photovoltaic Reference Cell
methodsapplyonlyatthetimeofthetest,andimplynopastor
future performance level. E1021TestMethodforSpectralResponsivityMeasurements
of Photovoltaic Devices
1.5 These test methods apply to photovoltaic modules and
E1040Specification for Physical Characteristics of Noncon-
arrays that do not contain series-connected photovoltaic mul-
centrator Terrestrial Photovoltaic Reference Cells
tijunction devices; such module and arrays should be tested
E1125 Test Method for Calibration of Primary Non-
according to Test Methods E2236.
Concentrator Terrestrial Photovoltaic Reference Cells Us-
1.6 The values stated in SI units are to be regarded as
ing a Tabular Spectrum
standard. No other units of measurement are included in this
E1362Test Methods for Calibration of Non-Concentrator
standard.
Photovoltaic Non-Primary Reference Cells
1.7 This standard does not purport to address all of the E2236Test Methods for Measurement of Electrical Perfor-
safety concerns, if any, associated with its use. It is the mance and Spectral Response of Nonconcentrator Multi-
responsibility of the user of this standard to establish appro- junction Photovoltaic Cells and Modules
priate safety, health, and environmental practices and deter- G173TablesforReferenceSolarSpectralIrradiances:Direct
mine the applicability of regulatory limitations prior to use. Normal and Hemispherical on 37° Tilted Surface
1.8 This international standard was developed in accor-
dance with internationally recognized principles on standard- 3. Terminology
ization established in the Decision on Principles for the
3.1 Definitions—Definitions of terms used in these test
Development of International Standards, Guides and Recom-
methods may be found in Terminology E772.
mendations issued by the World Trade Organization Technical
3.2 Definitions of Terms Specific to This Standard:
Barriers to Trade (TBT) Committee.
1 2
These test methods are under the jurisdiction of ASTM Committee E44 on For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Solar, Geothermal and Other Alternative Energy Sources and are the direct contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
responsibility of Subcommittee E44.09 on Photovoltaic Electric Power Conversion. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved April 1, 2019. Published April 2019. Originally the ASTM website.
approved in 1985. Last previous edition approved in 2015 as E1036–15. DOI: The last approved version of this historical standard is referenced on
10.1520/E1036-15R19. www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E1036 − 15 (2019)
TABLE 1 Reporting Conditions
3.2.1 nominal operating cell temperature, NOCT, n—the
temperature of a solar cell inside a module operating at an Device
Total Irradiance, Spectral
−2
Temperature,
−2
ambienttemperatureof20°C,anirradianceof800Wm ,and
Wm Irradiance
°C
−1
an average wind speed of 1 ms .
Standard reporting conditions 1000 G173 25
Nominal operating conditions 800 . NOCT
3.2.2 reporting conditions, RC, n—the device temperature,
total irradiance, and reference spectral irradiance conditions
that module or array performance data are corrected to.
3.3 Symbols:
4.3.1 The reference cell is chosen according to the spectral
3.3.1 Thefollowingsymbolsandunitsareusedinthesetest
distribution of the irradiance under which it was calibrated, for
methods:
example, the direct normal or global spectrum. These spectra
−1
α —temperature coefficient of reference cell I ,°C ,
r SC
are defined by Tables G173. The reference cell therefore
α—current temperature coefficient of device under test,
determines to which spectrum the test module or array perfor-
−1
°C ,
mance is referred.
β(E)—voltage temperature function of device under test,
4.3.2 The reference cell must match the device under test
−1
°C ,
2 −1 such that the spectral mismatch parameter is 1.00 6 0.05, as
C—calibration constant of reference cell, Am W ,
determined in accordance with Test Method E973.
2 −1
C'—adjustedcalibrationconstantofreferencecell,Am W ,
4.3.3 Recommended physical characteristics of reference
C—NOCT Correction factor,°C,
f
cells are described in Specification E1040.
δ(T)—voltageirradiancecorrectionfunctionofdeviceunder
4.3.4 Areferencemodulemaybeusedinsteadofareference
test, dimensionless,
cell throughout these test methods provided 4.3.2 is satisfied
∆T—NOCT cell-ambient temperature difference, °C,
and the short-circuit current of the reference module has been
−2
E—irradiance, Wm ,
determined according to the procedures in these test methods
−2
E —irradiance at RC, Wm ,
o
usingareferencecell.Thereferencemodulemustalsomeetthe
FF—fill factor, dimensionless,
module package design requirements in Specification E1040,
I—current, A,
with the exception of the electrical connector requirement.
I —current at maximum power, A,
mp
Ideally, electrical connections to an individual cell in the
I —current at RC, A,
o
reference module should be provided to allow for spectral
I —short-circuit current of reference cell (or module, see
r
responsivity measurement according to Test Method E1021.
1.1.1 and 4.3.4), A,
4.4 The spectral response of the module or array is usually
I —short-circuit current, A,
sc
taken to be that of a representative cell from the module or
M—spectral mismatch parameter, dimensionless,
array tested in accordance with Test Method E1021. The
P—electrical power, W,
representative cell should be packaged such that the optical
P —maximum power, W,
m
properties of the module or array packaging and the represen-
T—temperature, °C,
tative cell package are similar.
T —ambient temperature, °C,
a
T —temperature of cell in module, °C,
c 4.5 Thetestsareperformedusingeithernaturalorsimulated
T —temperature at RC, °C,
o
sunlight. Solar simulation requirements are stated in Specifi-
T —temperature of reference cell, °C,
r cation E927.
−1
ν—wind speed, ms ,
4.5.1 Ifapulsedsolarsimulatorisusedasalightsource,the
V—voltage, V,
transient responses of the module or array and the reference
—voltage at maximum power, V,
V
cell must be compatible with the test equipment.
mp
V —voltage at RC, V, and
o
4.6 The data from the measurements are translated to a set
V —open-circuit voltage, V.
oc
of reporting conditions (see 5.3) selected by the user of these
test methods. The actual test conditions, the test data (if
4. Summary of Test Methods
available), and the translated data are then reported.
4.1 Measurement of the performance of a photovoltaic
module or array illuminated by a light source consists of 5. Significance and Use
determining at least the following electrical characteristics:
5.1 Itistheintentoftheseprocedurestoproviderecognized
short-circuit current, open-circuit voltage, maximum power,
methods for testing and reporting the electrical performance of
and voltage at maximum power.
photovoltaic modules and arrays.
4.2 Theseparametersarederivedbyapplyingtheprocedure
5.2 The test results may be used for comparison of different
in Section 8 to a set of current-voltage data pairs (I-V data)
modulesorarraysamongagroupofsimilaritemsthatmightbe
recorded with the test module or array operating in the
encountered in testing a group of modules or arrays from a
power-producing quadrant.
single source. They also may be used to compare diverse
4.3 Testing the performance of a photovoltaic device in- designs, such as products from different manufacturers. Re-
volves the use of a calibrated photovoltaic reference cell to peatedmeasurementsofthesamemoduleorarraymaybeused
determine the total irradiance. for the study of changes in device performance.
E1036 − 15 (2019)
5.3 Measurements may be made over a range of test 6. Apparatus
conditions. The measurement data are numerically translated
6.1 PhotovoltaicReferenceCell—Acalibratedreferencecell
from the test conditions to standard RC, to nominal operating
is used to determine the total irradiance during the electrical
conditions, or to optional user-specified reporting conditions.
performance measurement.
Recommended RC are defined in Table 1.
6.1.1 The reference cell shall be matched in its spectral
5.3.1 If the test conditions are such that the device tempera-
response to a representative cell of the test module or array
ture is within 62°C of the RC temperature and the total
such that the spectral mismatch parameter as determined by
irradiance is within 65 % of the RC irradiance, the numerical
Test Method E973 is 1.00 6 0.05.
translation consists of a correction to the measured device
6.1.2 Specification E1040 provides recommended physical
current based on the total irradiance during the I-V measure-
characteristics of reference cells.
ment.
6.1.3 Reference cells may be calibrated in accordance with
5.3.2 Iftheprovisionin5.3.1isnotmet,performanceatRC
Test Methods E1125 or E1362, as appropriate for a particular
is obtained from four separate I-V measurements at tempera-
application.
tureandirradianceconditionsthatbracketthedesiredRCusing
6.1.4 A current measurement instrument (see 6.7) shall be
a bilinear interpolation method.
usedtodeterminetheI ofthereferencecellwhenilluminated
sc
5.3.2.1 There are a variety of methods that may be used to
with the light source (see 6.4).
bracket the temperature and irradiance. One method involves
6.2 Test Fixture— The device to be tested is mounted on a
cooling the module under test below the reference temperature
test fixture that facilitates temperature measurement and four-
andmakingrepeatedmeasurementsoftheI-Vcharacteristicsas
wire current-voltage measurements (Kelvin probe, see 6.3).
the module warms up. The irradiance of pulsed light sources
The design of the test fixture shall prevent any increase or
may be adjusted by using neutral density mesh filters of
decrease of the device output due to reflections or shadowing.
varying transmittance. If the distance between the simulator
Arrays installed in the field shall be tested as installed. See
and the test plane can be varied then this adjustment can be
7.2.3 for additional restrictions and reporting requirements.
usedtochangetheirradiance.Innaturalsunlight,theirradiance
6.3 KelvinProbe—Anarrangementofcontactsthatconsists
will change with the time of day or if the solar incidence angle
oftwopairsofwiresattachedtothetwooutputterminalsofthe
is adjusted.
device under test. One pair of wires is used to conduct the
5.4 These test methods are based on two requirements.
currentflowingthroughthedevice,andtheotherpairisusedto
5.4.1 First, the reference cell (or module, see 1.1.1 and
measure the voltage across the device.Aschematic diagram of
4.3.4) is selected so that its spectral response is considered to
an I-Vmeasurement using a Kelvin Probe is given in Fig. 1 of
be close to the module or array to be tested.
Test Method E948.
5.4.2 Second, the spectral response of a representative cell
6.4 Light Source— The light source shall be either natural
and the spectral distribution of the irradiance source must be
sunlight or a solar simulator providing Class A, B, or C
known. The calibration constant of the reference cell is then
simulation as specified in Specification E927.
corrected to account for the difference between the actual and
6.5 Temperature Measurement Equipment—The instrument
thereferencespectralirradiancedistributionsusingthespectral
or instruments used to measure the temperature of both the
mismatch parameter, which is defined in Test Method E973.
reference cell and the device under test shall have a resolution
5.5 Terrestrial reference cells are calibrated with respect to
of at least 0.1°C, and shall have a total error of less than 61°C
areferencespectralirradiancedistribution,forexample,Tables
of reading.
G173.
6.5.1 Temperature sensors, such as thermocouples or
thermistors, suitable for the test temperature range shall be
5.6 Areference cell made and calibrated as described in 4.3
attached in a manner that allows measurement of the device
will indicate the total irradiance incident on a module or array
temperature. Because module and array temperatures can vary
whose spectral response is close to that of the reference cell.
spatially under continuous illumination, multiple sensors dis-
5.7 With the performance data determined in accordance
tributed over the device should be used, and the results
with these test methods, it becomes possible to predict module
averaged to obtain the device temperature.
or array performance from measurements under any test light
6.5.2 When testing modules or arrays for which direct
source in terms of any reference spectral irradiance distribu-
measurement of the cell temperature inside the package is not
tion.
feasible,sensorscanbeattachedtotherearsideofthedevices.
The error due to temperature gradients will depend on the
5.8 The reference conditions of 5.3.1 must be met if the
thermal characteristics of the packaging, especially under
measured I-V curve exhibits “kinks” or multiple inflection
continuous illumination. Modules with glass back sheets will
points.
have higher gradients than modules with thin polymer backs,
for example.
6.6 Variable Load— An electronic load, such as a variable
Marion, B., Rummel, S., and Anderberg, A., “Current-Voltage Curve Transla-
tion by Bilinear Interpolation,” Prog. Photovolt: Res. Appl. 2004, 12:593–607. resistor, a programmable power supply, or a capacitive sweep
E1036 − 15 (2019)
circuit, used to operate the device to be tested at different 7.1.7.1 If the provision of 7.1.6 is met, it is not necessary to
points along its I-V characteristic. measure I at each operating point.
r
7.1.8 Measure the temperature of the reference cell, T , and
6.6.1 The variable load should be capable of operating the
r
device to be tested at an I-V point where the voltage is within the temperature of the test device, T . Temperature changes
c
during the test shall be less than 2°C.
1%of V in the power-producing quadrant.
oc
6.6.2 The variable load should be capable of operating the
7.2 Continuous Illumination Technique:
device to be tested at an I-V point where the current is within
7.2.1 This technique is valid for testing in continuous solar
1%of I in the power-producing quadrant.
sc
simulators or natural sunlight.
6.6.3 The variable load should allow the device output
7.2.2 Determine the spectral mismatch parameter, M, using
power (the product of device current and device voltage) to be
Test Method E973.
variedinincrementsassmallas0.2%ofthemaximumpower.
7.2.3 Mountthereferencecellandthedevicetobetestedin
6.6.4 The electrical response time of the variable load
the test fixture coplanar within 62°, and normal to the
should be fast enough to sweep the required range of I-V
illumination source within 610°. If an array or module cannot
operating points during the measurement period. It is possible
be aligned to within 610°, the solar angle of incidence, the
that the response time of the device under test may limit how
device orientation and its tilt angle must be reported with the
fast the range of I-V points can be swept, especially when
data.
pulsedsimulatorsareused.Forthesecases,itmaybenecessary
7.2.4 Connect the four-wire Kelvin probe to the module or
to make multiple measurements over smaller portions of the
array output terminals.
I-V curve to obtain the entire recommended range.
7.2.5 Expose the test device to the illumination source for a
period of time sufficient for the device to achieve thermal
6.7 Current Measurement Equipment—The instrument or
equilibrium.
instruments used to measure the current through the device
7.2.6 If the temporal instability of the light source (as
under test and the I of the reference cell shall have a
sc
defined in Specification E927) is less than 0.1%, the total
resolution of at least 0.05 % of the maximum current
irradiance may be determined with the reference cell prior to
encountered, and shall have a total error of less than
...