1、Designation: E973 15E973 16Standard Test Method forDetermination of the Spectral Mismatch Parameter Betweena Photovoltaic Device and a Photovoltaic Reference Cell 1This standard is issued under the fixed designation E973; the number immediately following the designation indicates the year oforiginal
2、 adoption or, in the case 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 provides a procedure for the determination of a sp
3、ectral mismatch parameter used in performance testingof photovoltaic devices.1.2 The spectral mismatch parameter is a measure of the error introduced in the testing of a photovoltaic device that is causedby the photovoltaic device under test and the photovoltaic reference cell having non-identical q
4、uantum efficiencies, as well asmismatch between the test light source and the reference spectral irradiance distribution to which the photovoltaic reference cellwas calibrated.1.2.1 Examples of reference spectral irradiance distributions are Tables E490 or G173.1.3 The spectral mismatch parameter ca
5、n be used to correct photovoltaic performance data for spectral mismatch error.1.4 Temperature-dependent quantum efficiencies are used to quantify the effects of temperature differences between testconditions and reporting conditions.1.5 This test method is intended for use with linear photovoltaic
6、devices in which short-circuit is directly proportional toincident irradiance.1.6 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.7 This standard does not purport to address all of the safety concerns, if any, associated wit
7、h its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E490 Standard Solar Constant and Zero Air Mass Solar Spectral Irradian
8、ce TablesE772 Terminology of Solar Energy ConversionE948 Test Method for Electrical Performance of Photovoltaic Cells Using Reference Cells Under Simulated SunlightE1021 Test Method for Spectral Responsivity Measurements of Photovoltaic DevicesE1036 Test Methods for Electrical Performance of Nonconc
9、entrator Terrestrial Photovoltaic Modules and Arrays UsingReference CellsE1125 Test 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 CellsG138 T
10、est Method for Calibration of a Spectroradiometer Using a Standard Source of IrradianceG173 Tables for Reference Solar Spectral Irradiances: Direct Normal and Hemispherical on 37 Tilted SurfaceSI10 Standard for Use of the International System of Units (SI): The Modern Metric System3. Terminology3.1
11、DefinitionsDefinitions of terms used in this test method may be found in Terminology E772.3.2 Definitions of Terms Specific to This Standard:1 This test method is under the jurisdiction of ASTM Committee E44 on Solar, Geothermal and Other Alternative Energy Sources and is the direct responsibility o
12、fSubcommittee E44.09 on Photovoltaic Electric Power Conversion.Current edition approved Dec. 1, 2015July 1, 2016. Published January 2016August 2016. Originally approved in 1983. Last previous edition approved in 2015 asE973 10(2015). 15. DOI: 10.1520/E0973-15.10.1520/E0973-16.2 For referencedASTM st
13、andards, 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 standard and is intended only to provide the user of an
14、 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 cases only the current versionof the standard as publis
15、hed 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 test light source, na source of illumination whose spectral irradiance will be used for the spectral mismatch calculation.The
16、light source may be natural sunlight or a solar simulator.3.3 Symbols: The following symbols and units are used in this test method:3.3.1 wavelength (m or nm).3.3.2 Das a subscript, refers to the device to be tested.3.3.3 Ras a subscript, refers to the reference cell.3.3.4 Sas a subscript, refers to
17、 the test light source.3.3.5 0as a subscript, refers to the reference spectral irradiance distribution.3.3.6 Aactive area, (m2).3.3.7 Eirradiance (Wm2).3.3.8 ES()spectral irradiance, test light source (Wm2m1 or Wm2nm1).3.3.9 E0()spectral irradiance, to which the reference cell is calibrated (Wm2m1 o
18、r Wm2nm1).3.3.9.1 DiscussionFollowing normal SI rules for compound units (see Practice SI10), the units for spectral irradiance, the derivative of irradiance,with respect to wavelength, dE/d, would be Wm3. However, to avoid possible confusion with a volumetric power density unitand for convenience i
19、n numerical calculations, it is common practice to separate the wavelength in the compound unit. Thiscompound unit is also used in Tables G173.3.3.10 Ishort-circuit current (A).3.3.11 JLlight-generated photocurrent density (Am2).3.3.12 Mspectral mismatch parameter (dimensionless).3.3.13 Q(,T)quantum
20、 efficiency (electrons per photon or %).3.3.14 ()partial derivative of quantum efficiency with respect to temperature (electrons per photonC1 or %C1).3.3.15 R()spectral responsivity (AW1).3.3.16 Ttemperature (C).3.3.17 TR0temperature, at which the reference cell is calibrated (C).3.3.18 TD0temperatu
21、re, to which the short-circuit current of the device to be tested will be reported (C).3.3.18.1 DiscussionWhen reporting photovoltaic performance to Standard Reporting Conditions (SRC), it is common for TR0 = TD0 = 25C.3.3.19 qelectron charge (C).3.3.20 hPlanck constant (Js).3.3.21 cspeed of light (
22、ms1).3.3.22 Ttemperature difference (C).3.3.23 measurement error in short-circuit current (dimensionless).4. Summary of Test Method4.1 Spectral mismatch error occurs when a calibrated reference cell is used to measure total irradiance of a test light source (suchas a solar simulator) during a photov
23、oltaic device performance measurement, and the incident spectral irradiance of the test lightsource differs from the reference spectral irradiance distribution to which the reference cell is calibrated.4.2 The magnitude of the error depends on how the quantum efficiencies of the photovoltaic referen
24、ce cell and the device tobe tested differ from one another; these quantum efficiencies vary with temperature.4.3 Determination of the spectral mismatch parameter M requires six spectral quantities.4.3.1 The spectral irradiance distribution of the test light source ES().4.3.2 The reference spectral i
25、rradiance distribution to which the photovoltaic reference cell was calibrated E0().4.3.3 Photovolatic Reference Cell:4.3.3.1 The quantum efficiency at the temperature corresponding to its calibration constant, QR(T0)4.3.3.2 The partial derivative of the quantum efficiency with respect to temperatur
26、e, R() = QR/T().4.3.4 Device to be Tested:E973 1624.3.4.1 The quantum efficiency at the temperature at which its performance will be reported, QD(,TD0).4.3.4.2 The derivative of the quantum efficiency with respect to temperature, R() = QD/T()4.4 Temperatures of both devices are measured, and M is ca
27、lculated using Eq 1 and numerical integration.5. Significance and Use5.1 The calculated error in the photovoltaic device current determined from the spectral mismatch parameter can be used todetermine if a measurement will be within specified limits before the actual measurement is performed.5.2 The
28、 spectral mismatch parameter also provides a means of correcting the error in the measured device current due to spectralmismatch.5.2.1 The spectral mismatch parameter is formulated as the fractional error in the short-circuit current due to spectral andtemperature differences.5.2.2 Error due to spe
29、ctral mismatch is corrected by multiplying a reference cells measured short-circuit current by M, atechnique used in Test Methods E948 and E1036.5.3 Because all spectral quantities appear in both the numerator and the denominator in the calculation of the spectral mismatchparameter (see 8.1), multip
30、licative calibration errors cancel, and therefore only relative quantities are needed (although absolutespectral quantities may be used if available).5.4 Temperature-dependent spectral mismatch is a more accurate method to correct photovoltaic current measurementscompared with fixed-value temperatur
31、e coefficients.36. Apparatus6.1 Quantum Effciency Measurement ApparatusAs required by Test Method E1021 for spectral responsivity measurements.6.2 Spectral Irradiance Measurement EquipmentA spectroradiometer as defined and required by Test Method G138 andcalibrated according to Test Method G138.6.2.
32、1 The wavelength resolution shall be no greater than 10 nm.6.2.2 It is recommended that the wavelength pass-bandwith be no greater than 6 nm.6.2.3 The wavelength range should be wide enough to include the quantum efficiencies of both the photovoltaic device to betested and the photovoltaic reference
33、 cell.6.2.4 The spectroradiometer must be able to scan the required wavelength range in a time period short enough such that thespectral irradiance at any wavelength does not vary more than 65 % during the entire scan.6.2.5 Test Methods E948, E1036, and E1125 provide additional guidance for spectral
34、 irradiance measurements.6.3 Temperature Measurement EquipmentAs required by Test Method E948 or Test Methods E1036.7. Procedure7.1 Obtain the reference spectral irradiance distribution, E0(), to which the photovoltaic reference cell is calibrated, such asTables E490 or G173.7.2 Obtain the quantum e
35、fficiency of the photovoltaic reference cell at its calibration temperature, QR(,TR0).7.2.1 An expression that converts spectral responsivity to quantum efficiency is provided in Test Methods E1021.NOTE 1Test Methods E1125 and E1362 require the spectral responsivity to be provided as part of the ref
36、erence cell calibration certificate.7.3 Obtain the partial derivative of quantum efficiency with respect to temperature, R(), for the photovoltaic reference cell(see 8.1).7.3.1 If R() is not provided with the calibration certificate of the photovoltaic reference cell, the derivatiave function mustbe
37、 calculated from a series of quantum efficiency measurements at several temperatures. An acceptable procedure is given inAnnex A1.7.4 Measure the quantum efficiency of the photovoltaic device to be tested at the temperature to which its performance will bereported, QD(,TD0), and its partial derivati
38、ve of quantum efficiency with respect to temperature, D(), using the procedure givenin Annex A1(see also 8.1).7.5 Measure the spectral irradiance, ES(), of the test light source, using the spectral irradiance measurement equipment (see6.2.1).7.6 Measure the temperature of the photovoltaic reference
39、cell, TR, using the temperature measurement equipment.7.7 Measure the temperature of the photovoltaic device to be tested, TD, using the temperature measurement equipment.3 Osterwald, C. R., Campanelli, M., Moriarty, T., Emery, K. A., and Williams, R., “Temperature-Dependent Spectral Mismatch Correc
40、tions,” IEEE Journal ofPhotovoltaics, Vol 5, No. 6, November 2015, pp. 16921697. DOI:10.1109/JPHOTOV.2015.2459914E973 1638. Calculation of Results8.1 Calculate the spectral mismatch parameter with:3M 5*12QD,TD0!ES!d1TD*12D! ES!d*34QR ,TR0!ES!d1TR*34R!ES!d 3*34QR ,TR0!E0!d*12QD ,TD0!E0!d , (1)where T
41、R = TR TR0 and TD = TD TD0. Use an appropriate numerical integration scheme such as that described in TablesG173. Appendix X1 provides the derivation of Eq 1. If ?TR? 0.5C and ?TD? 0.5C, then R() and D() may be omittedand Eq 1 simplified to:M 5*12QD,TD0!ES!d*34 QR,TR0!ES!d 3*34QR ,TR0!E0!d*12QD ,TD0
42、!E0!d, (2)8.1.1 The wavelength integration limits 1 and 2 shall correspond to the spectral response limits of the photovoltaic device.8.1.2 The wavelength integration limits 3 and 4 shall correspond to the spectral response limits of the photovoltaic referencecell.8.2 OptionalCalculate the measureme
43、nt error due to spectral mismatch using:5?M 21? (3)9. Precision and Bias9.1 PrecisionImprecision in the spectral irradiance and the spectral response measurements will introduce errors in thecalculated spectral mismatch parameter.9.1.1 It is not practicable to specify the precision of the spectral m
44、ismatch test method using results of an interlaboratory study,because such a study would require circulating at least six stable test light sources between all participating laboratories.9.1.2 Monte-Carlo perturbation simulations4 using precision errors as large as 5 % in the spectral measurements h
45、ave shownthat the imprecision associated with the calculated spectral mismatch parameter is no more than 1 %.9.1.3 Table 1 lists estimated maximum limits of imprecision that may be associated with spectral measurements at any onewavelength.9.2 BiasBias associated with the spectral measurements used
46、in the spectral mismatch calculation can be either independentof wavelength or can vary with wavelength.9.2.1 Numerical calculations using wavelength-independent bias errors of 2 % added to the spectral quantities show the errorintroduced in the spectral mismatch parameter to be less than 1 %.9.2.2
47、Estimates of maximum bias that may be associated with the spectral measurements are listed in Table 2. These limits arelisted for guidance only and in actual practice will depend on the calibration of the spectral measurements.10. Keywords10.1 cell; mismatch; photovoltaic; reference; solar; spectral
48、; testing4 Emery, K. A., Osterwald, C. R., and Wells, C. V., “Uncertainty Analysis of Photovoltaic Efficiency Measurements,” Proceedings of the 19th IEEE PhotovoltaicsSpecialists Conference1987, pp. 153159, Institute of Electrical and Electronics Engineers, New York, NY, 1987.TABLE 1 Estimated Limit
49、s of Imprecision in SpectralMeasurementsSource of Imprecision Estimated Limit, %Spectral response measurement 2.0Spectral irradiance measurement 5.0E973 164ANNEX(Mandatory Information)A1. DETERMINATION OF THE TEMPERATURE DEPENDENCE OF PHOTOVOLTAIC DEVICE QUANTUM EFFICIENCYA1.1 Accurate reporting of photovoltaic device performance over temperature requires kno
