1、Designation: E948 15E948 16Standard Test Method forElectrical Performance of Photovoltaic Cells UsingReference Cells Under Simulated Sunlight1This standard is issued under the fixed designation E948; the number immediately following the designation indicates the year oforiginal adoption or, in the c
2、ase of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of the electrical performance of a photovoltaic
3、 cell under simulated sunlight bymeans of a calibrated reference cell procedure.1.2 Electrical performance measurements are reported with respect to a select set of standard reporting conditions (SRC) (seeTable 1) or to user-specified conditions.reporting conditions. In either case, the chosen repor
4、ting conditions are abbreviated as RC.1.2.1 The SRC or user-specified conditions RC include the cell temperature, the total irradiance, and the reference spectralirradiance distribution.1.3 This test method is applicable only to photovoltaic cells with a linear response over the range of interest.sh
5、ort-circuit currentversus total irradiance response up to and including the total irradiance used in the measurement.1.4 The cell parameters determined by this test method apply only at the time of test, and imply no past or future performancelevel.1.5 The values stated in SI units are to be regarde
6、d as standard. No other units of measurement are included in this standard.1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determin
7、e the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E490 Standard Solar Constant and Zero Air Mass Solar Spectral Irradiance TablesE491 Practice for Solar Simulation for Thermal Balance Testing of SpacecraftE691 Practice for Conducting an Interlaborat
8、ory Study to Determine the Precision of a Test MethodE772 Terminology of Solar Energy ConversionE927 Specification for Solar Simulation for Photovoltaic TestingE973 Test Method for Determination of the Spectral Mismatch Parameter Between a Photovoltaic Device and a PhotovoltaicReference CellE1125 Te
9、st Method for Calibration of Primary Non-Concentrator Terrestrial Photovoltaic Reference Cells Using a TabularSpectrumE1362 Test Methods for Calibration of Non-Concentrator Photovoltaic Non-Primary Reference CellsG173 Tables for Reference Solar Spectral Irradiances: Direct Normal and Hemispherical o
10、n 37 Tilted Surface3. Terminology3.1 DefinitionsDefinitions of terms used in this test method may be found in Terminology E772 and in Specification E927.3.2 Definitions of Terms Specific to This Standard:3.2.1 cell temperature, C, effective irradiance, nthe temperature of the semiconductor junction
11、of a photovoltaiccell.irradiance that a solar simulator produces as measured by a cells short-circuit current relative to a reference value for the cellsshort-circuit current at a particular RC.1 This test method is under the jurisdiction of ASTM Committee E44 on Solar, Geothermal and Other Alternat
12、ive Energy Sources and is the direct responsibility ofSubcommittee E44.09 on Photovoltaic Electric Power Conversion.Current edition approved Feb. 1, 2015Nov. 1, 2016. Published March 2015December 2016. Originally approved in 1993. Last previous edition approved in 20092015 asE948 09.E948 15. DOI: 10
13、.1520/E0948-15.10.1520/E0948-16.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM
14、standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all
15、cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.2.1.1 DiscussionThis reference value typically corresponds to a different s
16、pectral irradiance distribution than the solar simulator.3.2.2 junction temperature, reporting conditions, RC, nsynonym forthe reference cell temperature.spectral irradiancedistribution, total irradiance, and cell temperature to which the photovoltaic current-voltage performance is measured andcorre
17、cted.3.2.3 light source,test cell, na source of radiant energy used for cell performance measurements that simulates naturalsunlight. the photovoltaic cell to be tested, or cell under test, using the method described herein.3.3 Symbols:Symbols3.3.1 The following symbols and units are used in this te
18、st method:Acell area, m2rtemperature coefficient of reference cell, C1Ccalibration constant of reference cell, Am2W1CTtransfer calibration ratio, dimensionlessEirradiance, Wm2Eostandard reporting irradiance, Wm2efficiency, %FFfill factor, %Icurrent, AImmonitor solar cell short-circuit current, AIocu
19、rrent with respect to SRC, AIrreference cell short-circuit current, AIscshort-circuit current, AMspectral mismatch parameter, dimensionlessPmmaximum power, WRsseries resistance, Ttemperature, CTostandard reporting temperature, CTrtemperature of reference cell, CVvoltage, VVovoltage with respect to S
20、RC, VVocopen-circuit voltage, VThe following symbols and units are used in this test method:3.3.1 0as a subscript, denotes a value under the specified RC.3.3.2 Aarea of the test cell, (m2).3.3.3 ARarea of the reference cell, (m2).3.3.4 CRcalibration constant of reference cell, (Am2W1).3.3.5 CTtransf
21、er calibration ratio, (dimensionless).3.3.6 Etotal irradiance, Wm2.3.3.7 FFfill factor, (%).3.3.8 Icurrent of the test cell (A).3.3.9 IMPcurrent of the test cell at maximum power in the power-producing quadrant (A).3.3.10 ISCshort-circuit current of the test cell (A).3.3.11 ISC,Rshort-circuit curren
22、t of the reference cell (A).3.3.12 ISC,Mshort-circuit current of the monitor cell (A).3.3.13 Mspectral mismatch parameter (dimensionless).3.3.14 PMPmaximum power of the test cell in the power-producing quadrant (W).TABLE 1 Standard Reporting ConditionsReference Spectral IrradianceDistributionTotalIr
23、radianceIrradiance,E0(Wm2 )TemperatureCellTemperature, T0(C)Tables G173 Direct Normal 1000 25Tables G173 Direct Normal 900 25Tables G173 Hemispherical 1000 25Tables E490 1366.1 25E948 1623.3.15 RSseries resistance of the test cell ().3.3.16 Scurrent correction factor due to spatial non-uniformity of
24、 irradiance (dimensionless).3.3.17 Ttemperature of the test cell (C).3.3.18 TRtemperature of the reference cell (C).3.3.19 U0ordered set of test cell current, voltage, and power values at RC (A, V, W).3.3.20 Vvoltage of the test cell (V).3.3.21 VMPvoltage of the test cell at maximum power in the pow
25、er-producing quadrant (V).3.3.22 VOCopen-circuit voltage of the test cell (V).3.3.23 efficiency (%).4. Summary of Test Method4.1 The performance test of a photovoltaic cell consists of measuring the electrical current versus voltage (I-V) characteristicof the cell while illuminated by a suitable lig
26、ht source.solar simulator and with its temperature sufficiently controlled.4.2 A calibrated photovoltaic reference cell (see 6.1) is used to determine the totaleffective irradiance during the test and toaccount for the spectral distribution of the light source.test.4.3 Simulated sunlight is used as
27、the light source for the electrical performance measurement, and solar simulation requirementsare defined in Specification E927 (terrestrial applications) and Practice E491 (space applications).4.4 The data from the measurements are corrected to standard reporting conditions, or to optional user-spe
28、cified reportingconditions. The standard reporting conditions the desired RC. Three possible SRC are defined in Table 1.4.4.1 Measurement error in test cell current caused by deviations of the irradiance conditions from the SRCRC is correctedusing the totaleffective irradiance measured with the refe
29、rence cell and the spectral mismatch parameter, M, which is determinedin accordance with Test Method E973.4.4.1.1 This test method does not apply corrections to cell voltage for irradiance deviations, thus the solar simulator irradiancemust be sufficiently well controlled to accurately determine oth
30、er parameters under RC, especially maximum power andopen-circuit voltage. To this end, the effective irradiance during the measurement is restricted to be within 62 % of the RCirradiance. However, there will still be measurement uncertainty due to irradiance variations in this range.4.4.2 Measuremen
31、t error caused by deviation of the cell temperature test-cell and reference-cell temperatures from the SRCRCis minimized by maintaining the cell temperature temperatures sufficiently close to the required value (seeRC value. 7.10). To thisend, the test cell temperature during the measurement is rest
32、ricted to be within 61 C of the RC temperature.4.4.2.1 Test Method E973 provides for correction of test cell current through a temperature-dependent spectral mismatchparameter, M(T); however, Test Method E973 allows the temperature correction to be bypassed if the temperature is within 61C.4.4.2.2 T
33、his test method does not apply corrections to cell voltage for temperature deviations, thus the test-cell temperature mustbe sufficiently well controlled to accurately determine other parameters under RC, especially maximum power and open-circuitvoltage. However, there will still be measurement unce
34、rtainty due to temperature variations in this range.4.4.3 The measurement procedure employs a reference cell-test cell substitution technique that is designed to minimize errorsin short-circuit current caused by spatial non-uniformity of the solar simulator irradiance. A correction for spatial non-u
35、niformityof irradiance may be applied to measured current data if the reference cell and test cell have different areas; the correction is definedas the ratio of the effective irradiance in the solar simulator over the area of the test cell to the effective irradiance over the areaof the reference c
36、ell.5. Significance and Use5.1 It is the intent of this test method to provide a recognized method This test method provides a procedure for testing andreporting the electrical performance of photovoltaic cells.5.2 The test results may be used for comparison of cells among a group of similar cells o
37、r to compare diverse designs, suchas different manufacturers products. Repeated measurements of the same cell may be used to study changes in deviceperformance.5.3 This test method determines the electrical performance of a cell based upon the output power photovoltaic cell at a singleinstant of tim
38、e. It does not provide for integrating the output power over a given period of time and conditions to predict an energyoutput.time and the results do no imply any past or future performance.5.4 This test method requires a linear reference cell calibrated with respect to an appropriate reference spec
39、tral irradiancedistribution, such as Tables E490, or G173. It is the responsibility of the user to determine which reference spectral irradiancedistribution is appropriate for a particular application.E948 1636. Apparatus6.1 Photovoltaic Reference CellA calibrated reference linear, calibrated, photo
40、voltaic solar cell used to determine the totalirradiance during the electrical performance measurement.6.1.1 Reference cells may be calibrated in accordance with Test Methods E1125 or E1362, as is appropriate for a particularapplication.NOTE 1No reference cell calibration standards presently exist f
41、or space applications, although procedures such as using high-altitude balloon andlow-earth orbit flights are being used to calibrate such reference cells.6.1.2 The calibration constant, C,CR, of the reference cell mustshall be with respect to the reference spectral irradiancedistribution of the des
42、ired SRCRC (see 1.2).6.1.3 A current measurement instrument (see 6.3) shall be used to determine the Ishort-circuitsc current of the reference cellunder the light source.solar simulator.6.1.4 Special CaseIf the test cell also qualifies as a reference cell in that its ISC or calibration constant at t
43、he RC is knownprior to test, the test cell may be used to measure irradiance by itself and the separate reference cell omitted. The self-irradiancemeasurement technique is typically used to determine the fill factor of a reference cell post-calibration, and as a check for damageor degradation.6.2 Te
44、st FixtureBoth the cell to be tested test cell and the reference cell are mounted in a fixture that meets the followingrequirements.requirements:6.2.1 The test fixture shall ensure a uniform lateral temperature distribution to within 60.5C during the performancemeasurement.6.2.2 The test fixture sha
45、ll include a provision for maintaining a constant cell temperature for both the reference cell and thecell to be tested test cell (see 7.107.11).NOTE 2When using pulsed or shuttered light sources,solar simulators, it is possible that the cell temperature will increase upon initial illumination,even
46、when the cell temperature is controlled.6.2.3 The test fixture, when placed in the simulated sunlight,solar simulator, shall ensure that the field-of-viewfields-of-view ofboth the reference cell and the cell to be tested test cell are identical.NOTE 3Some solar simulators may have significant amount
47、s of irradiation from oblique or non-perpendicular angles to the test plane. In these cases,it is important that the cell to be tested test cell and the reference cell have similar reflectance and cosine-responseangular-response characteristics.6.2.4 A four-terminal connection (also known as a Kelvi
48、n connection, see Fig. 1) from the test cell to be tested to the I-Vmeasurement instrumentation (see 6.3 6.5) shall be used.6.3 Current Measurement EquipmentElectrical instrumentation used to measure the current through the test cell under testduring the performance measurement. The instrumentation
49、shall have a resolution of at least 0.02 % of the maximum currentencountered, and shall have a total error of less than 0.1 % of the maximum current encountered.6.3.1 The instrumentation shall be capable of simultaneously measuring data points with the short-circuit current currentmeasurement equipment shall measure data points simultaneously with the voltage (see 6.96.4) and voltage short-circuit current(see 6.46.9) measurement equipment, to within 10 s.6.4 Voltage Measurement EquipmentEl
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