1、Designation: E1125 16Standard Test Method forCalibration of Primary Non-Concentrator TerrestrialPhotovoltaic Reference Cells Using a Tabular Spectrum1This standard is issued under the fixed designation E1125; the number immediately following the designation indicates the year oforiginal adoption or,
2、 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 is intended for calibration and charac-terization of primary te
3、rrestrial photovoltaic reference cells toa desired reference spectral irradiance distribution, such asTables G173. The recommended physical requirements forthese reference cells are described in Specification E1040.Reference cells are principally used in the determination of theelectrical performanc
4、e of photovoltaic devices.1.2 Primary photovoltaic reference cells are calibrated innatural sunlight using the relative quantum efficiency of thecell, the relative spectral distribution of the sunlight, and atabulated reference spectral irradiance distribution. Selectionof the reference spectral irr
5、adiance distribution is left to theuser.1.3 This test method requires the use of a pyrheliometer thatis calibrated according to Test Method E816, which requiresthe use of a pyrheliometer that is traceable to the WorldRadiometric Reference (WRR). Therefore, reference cellscalibrated according to this
6、 test method are traceable to theWRR.1.4 This test method is used to calibrate primary referencecells; Test Method E1362 may be used to calibrate secondaryand non-primary reference cells (these terms are defined inTerminology E772).1.5 This test method applies only to the calibration of aphotovoltai
7、c cell that shows a linear dependence of its short-circuit current on irradiance over its intended range of use, asdefined in Test Method E1143.1.6 This test method applies only to the calibration of areference cell fabricated with a single photovoltaic junction.1.7 The values stated in SI units are
8、 to be regarded asstandard. No other units of measurement are included in thisstandard.1.8 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices
9、and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E490 Standard Solar Constant and Zero Air Mass SolarSpectral Irradiance TablesE772 Terminology of Solar Energy ConversionE816 Test Method for Calibration of Pyrheliometers byComparison
10、to Reference PyrheliometersE927 Specification for Solar Simulation for PhotovoltaicTestingE948 Test Method for Electrical Performance of Photovol-taic Cells Using Reference Cells Under Simulated Sun-lightE973 Test Method for Determination of the Spectral Mis-match Parameter Between a Photovoltaic De
11、vice and aPhotovoltaic Reference CellE1021 Test Method for Spectral Responsivity Measurementsof Photovoltaic DevicesE1040 Specification for Physical Characteristics of Noncon-centrator Terrestrial Photovoltaic Reference CellsE1143 Test Method for Determining the Linearity of aPhotovoltaic Device Par
12、ameter with Respect To a TestParameterE1362 Test Methods for Calibration of Non-ConcentratorPhotovoltaic Non-Primary Reference CellsE2554 Practice for Estimating and Monitoring the Uncer-tainty of Test Results of a Test Method Using ControlChart TechniquesG138 Test Method for Calibration of a Spectr
13、oradiometerUsing a Standard Source of IrradianceG173 Tables for Reference Solar Spectral Irradiances: DirectNormal and Hemispherical on 37 Tilted Surface1This test method is under the jurisdiction of ASTM Committee E44 on Solar,Geothermal and OtherAlternative Energy Sources and is the direct respons
14、ibility ofSubcommittee E44.09 on Photovoltaic Electric Power Conversion.Current edition approved July 1, 2016. Published October 2016. Originallyapproved in 1986. Last previous edition approved in 2015 as E1125 10 (2015).DOI: 10.1520/E1125-16.2For referenced ASTM standards, visit the ASTM website, w
15、ww.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1G183
16、 Practice for Field Use of Pyranometers, Pyrheliom-eters and UV Radiometers2.2 WMO Document:3WMO-No. 8 Guide to Meteorological Instruments andMethods of Observation, Seventh ed., 2008.3. Terminology3.1 DefinitionsDefinitions of terms used in this testmethod may be found in Terminology E772.3.2 The f
17、ollowing symbols and units are used in this testmethod:3.3 Symbols:3.3.1 Axcollimator aperture identifiers (non-numeric).3.3.2 Ccalibration value, reference cell (Am2W1).3.3.3 Carray of calibration values, reference cell(Am2W1).3.3.4 Das a subscript, refers to the reference cell to becalibrated; as
18、a variable, distance from collimator entranceaperture to reference cell top surface, or to spectroradiometerentrance optics (m).3.3.5 Etotal irradiance, measured with pyrheliometer(Wm2).3.3.6 Earray of measured total irradiance values (Wm2).3.3.7 E()spectral irradiance (Wm2m1or Wm2nm1).3.3.8 ES()mea
19、sured solar spectral irradiance (Wm2m1or WM2nm1).3.3.9 E0()reference spectral irradiance distribution(Wm2m1or WM2nm1).3.3.10 Fspectral correction factor (dimensionless).3.3.11 FOVfield-of-view ().3.3.12 Ishort-circuit current, reference cell (A).3.3.13 Iarray of measured short-circuit currents, refe
20、rencecell (A).3.3.14 ias a subscript, refers to the ith current andirradiance data point (dimensionless).3.3.15 jas a subscript, refers to the jth calibration valuedata point (dimensionless).3.3.16 Lcollimator length (m).3.3.17 nnumber of current and irradiance data pointsmeasured during calibration
21、 time period (dimensionless).3.3.18 mnumber of calibration value data points (dimen-sionless).3.3.19 Mspectral mismatch parameter (dimensionless).3.3.20 OD(,T)quantum efficiency, reference cell (%).3.3.21 rxcollimator inner aperture radius (m).3.3.22 Rcollimator entrance aperture radius (m).3.3.23 R
22、Epyrheliometer to integrated spectral irradianceratio (dimensionless).3.3.24 RNGas a subscript, refers to the minimum-to-maximum range of an array of values.3.3.25 ssample standard deviation, reference cell calibra-tion value (Am2W1).3.3.26 Ttemperature (C).3.3.27 T0calibration temperature, referenc
23、e cell (25C).3.3.28 ZP()pyrheliometer spectral transmittance function(dimensionless).3.3.29 wavelength (m or nm).3.3.30 Ocollimator opening angle ().3.3.31 Scollimator slope angle ().3.3.32 D()partial derivative of quantum efficiency withrespect to temperature (%C1).4. Summary of Test Method4.1 The
24、calibration of a primary photovoltaic reference cellconsists of measuring the short-circuit current of the cell whenilluminated with natural sunlight, along with the direct solarirradiance using a pyrheliometer (see Terminology E772). Theratio of the short-circuit current of the cell to the irradian
25、ce iscalled the responsivity, which, when divided by a spectralcorrection factor similar to the spectral mismatch parameterdefined in Test Method E973, is the calibration value for thereference cell. The spectral correction factor also corrects thecalibration value to 25C (see 4.2.2).4.1.1 The relat
26、ive spectral irradiance of the sunlight ismeasured using a spectroradiometer as specified in TestMethod G138 and Test Method E973.4.1.2 A pyrheliometer measures direct solar irrradiance byrestricting the field-of-view (FOV) to a narrow conical solidangle, typically 5, that includes the 0.5 cone subt
27、ended by thesun. This calibration method requires that the same irradiancemeasured by the pyrheliometer also illuminate the primaryreference cell to be calibrated and the spectroradiometersimultaneously. Thus, both are required to have collimators(see 6.2).4.1.3 Multiple calibration values determine
28、d from I, E, andE() measurements made on a minimum of three differentdays, are averaged to produce the final calibration result. Eachdata point corresponds to a single E() spectral irradiance.4.2 The following is a list of measurements that are used tocharacterize reference cells and are reported wi
29、th the calibra-tion data:4.2.1 The relative quantum efficiency of the cell is deter-mined in accordance with Test Methods E1021.4.2.2 Temperature sensitivity of the cells short-circuit cur-rent is determined experimentally by measuring the partialderivative of quantum efficiency with respect to temp
30、erature,as specified in Test Method E973.4.2.3 Linearity of short-circuit current versus irradiance isdetermined in accordance with Test Method E1143.4.2.4 The fill factor of the reference cell is determined usingTest Method E948. Providing the fill factor with the calibrationdata allows the referen
31、ce cell to be checked in the future forelectrical degradation or damage.3Available from World Meteorological Organization (WMO), 7bis, avenue de laPaix, Case Postale No. 2300, CH-1211 Geneva 2, Switzerland, http:/www.wmo.int.E1125 1625. Significance and Use5.1 The electrical output of a photovoltaic
32、 device is depen-dent on the spectral content of the illumination source, itsintensity, and the device temperature. To make standardized,accurate measurements of the performance of photovoltaicdevices under a variety of light sources when the intensity ismeasured with a calibrated reference cell, it
33、 is necessary toaccount for the error in the short-circuit current that occurs ifthe relative quantum efficiency of the reference cell is notidentical to the quantum efficiency of the device to be tested.Asimilar error occurs if the spectral irradiance distribution of thetest light source is not ide
34、ntical to the desired reference spectralirradiance distribution. These errors are accounted for by thespectral mismatch parameter (described in Test Method E973),which is a quantitative measure of the error in the short-circuitcurrent measurement. It is the intent of this test method toprovide a rec
35、ognized procedure for calibrating, characterizing,and reporting the calibration data for primary photovoltaicreference cells using a tabular reference spectrum.5.2 The calibration of a reference cell is specific to aparticular spectral irradiance distribution. It is the responsibil-ity of the user t
36、o specify the applicable irradiance distribution,for example Tables G173. This test method allows calibrationwith respect to any tabular spectrum.5.2.1 Tables G173 do not provide spectral irradiance datafor wavelengths longer than 4 m, yet pyrheliometers (see 6.1)typically have response in the 410 m
37、 region. To mitigate thisdiscrepancy, the Tables G173 spectra must be extended withthe data provided in Annex A2.5.3 A reference cell should be recalibrated at yearlyintervals, or every six months if the cell is in continuous useoutdoors.5.4 Recommended physical characteristics of referencecells can
38、 be found in Specification E1040.5.5 High-quality silicon primary reference cells are ex-pected to be stable devices by nature, and as such can beconsidered control samples. Thus, the calibration value datapoints (see 9.3) can be monitored with control chart techniquesaccording to Practice E2554, an
39、d the test result uncertaintyestimated. The control charts can also be extended with datapoints from previous calibrations to detect changes to thereference cell or the calibration procedures.6. Apparatus6.1 Pyrheliometer A secondary reference pyrheliometerthat is calibrated in accordance with Test
40、Method E816,oranabsolute cavity radiometer. See also World Radiometric Ref-erence in Terminology E772 and the World MeteorologicalOrganization (WMO) guide WMO-No.8, Chapter 7. PracticeG183 provides guidance to the use of pyrheliometers for directsolar irradiance measurements.6.1.1 Because secondary
41、reference pyrheliometers are cali-brated against an absolute cavity radiometer, the total uncer-tainty in the primary reference cell calibration value will bereduced if an absolute cavity radiometer is used.6.1.2 The spectral transmittance function of the pyrheliom-eter must be considered. For an ab
42、solute cavity radiometerwithout a window, ZP() can be assumed to be one over a verywide wavelength range. Secondary reference pyrheliometerstypically have a window at the entrance aperture, so ZP() canbe assumed to be the spectral transmittance of the windowmaterial.6.1.2.1 Test Method E816 requires
43、 absolute cavity radiom-eters to be “nonselective over the range from 0.3 to 10 m”,and secondary reference pyrheliometers to be “nonselectiveover the range from 0.3 to 4 m.”6.1.2.2 Commercially available secondary pyrheliometersuse a variety of different window materials, and many do notmeet the 0.3
44、 to 4 m requirement of Test Method E816. Thetransmittance of fused silica (SiO2), for example, has signifi-cant variations in the 2 to 4 m region that depend on the gradeof the material (ultraviolet or infrared grade). Sapphire (Al2O3)transmits beyond 4 m, but its transmittance is not entirely flato
45、ver 0.4 to 4 m. Crystalline quartz (SiO2) is very flat over 0.25to 2.5 m, but the transmittance falls to zero by 4 m. Thepyrheliometer manufacturer should be consulted to obtain thewindow transmittance data.6.1.2.3 The calibration procedure in Test Method E816places restrictions on allowable atmosph
46、eric conditions anddoes not adjust calibration results with spectral information: allpyrheliometers are calibrated with the same procedure regard-less of the window material.6.2 CollimatorsTubes with internal baffles, intended forpointing toward the sun, that restrict the FOV and are fitted tothe re
47、ference cell to be calibrated and the spectroradiometer(see 6.3); an acceptable collimator design is provided in AnnexA1. The collimators must match the FOV of the pyrheliometer(see A1.4.1).6.2.1 Eliminate or minimize any stray light entering thecollimators at the bottoms of the tubes.6.2.2 The rece
48、iving aperture of the reference cell collimatorshall be sized such that the entire optical surface of the primaryreference cell to be calibrated is completely illuminated,including the window (see Specification E1040). Thus, for areference cell with a 50 mm square window, the collimatorwould require
49、 a receiving aperture radius equal to:=502150225 35.4 mm6.3 Spectroradiometer, as required by Test Methods G138and E973 for direct normal solar spectral irradiance measure-ments.6.3.1 The wavelength range of the spectral irradiance mea-surement shall be wide enough to span the wavelength range ofthe quantum efficiency of the cell to be calibrated (see 6.7.3)and the spectral sensitivity function of the pyrheliometer (see6.1.2).6.3.2 If the spectral irradiance measurement is unable tomeasur
