1、Designation: E2236 10 (Reapproved 2015)Standard Test Methods forMeasurement of Electrical Performance and SpectralResponse of Nonconcentrator Multijunction PhotovoltaicCells and Modules1This standard is issued under the fixed designation E2236; the number immediately following the designation indica
2、tes the year oforiginal 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 These test methods provide special technique
3、s needed todetermine the electrical performance and spectral response oftwo-terminal, multijunction photovoltaic (PV) devices, bothcell and modules.1.2 These test methods are modifications and extensions ofthe procedures for single-junction devices defined by TestMethods E948, E1021, and E1036.1.3 T
4、hese test methods do not include temperature andirradiance corrections for spectral response and current-voltage(I-V) measurements. Procedures for such corrections are avail-able in Test Methods E948, E1021, and E1036.1.4 These test methods may be applied to cells and modulesintended for concentrato
5、r applications.1.5 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.6 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
6、 establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E772 Terminology of Solar Energy ConversionE927 Specification for Solar Simulation for PhotovoltaicTestingE948 Test Method for Electr
7、ical 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 Device and aPhotovoltaic Reference CellE1021 Test Method for Spectral Responsivity Measurementsof Photovoltaic DevicesE
8、1036 Test Methods for Electrical Performance of Noncon-centrator Terrestrial Photovoltaic Modules and ArraysUsing Reference CellsE1040 Specification for Physical Characteristics of Noncon-centrator Terrestrial Photovoltaic Reference CellsE1125 Test Method for Calibration of Primary Non-Concentrator
9、Terrestrial Photovoltaic Reference Cells Us-ing a Tabular SpectrumE1328 Terminology Relating to Photovoltaic Solar EnergyConversion (Withdrawn 2012)3E1362 Test Method for Calibration of Non-ConcentratorPhotovoltaic Secondary Reference CellsG138 Test Method for Calibration of a SpectroradiometerUsing
10、 a Standard Source of IrradianceG173 Tables for Reference Solar Spectral Irradiances: DirectNormal and Hemispherical on 37 Tilted Surface3. Terminology3.1 Definitionsdefinitions of terms used in this standardmay be found in Terminology E772 and in TerminologyE1328.3.2 Definitions of Terms Specific t
11、o This Standard:3.2.1 multijunction device, na photovoltaic device com-posed of more than one photovoltaic junction stacked on top ofeach other and electrically connected in series.3.2.2 component cells, nthe individual photovoltaic junc-tions of a multijunction device.3.3 Symbols:1These test method
12、s are under the jurisdiction of ASTM Committee E44 onSolar, Geothermal and Other Alternative Energy Sources and is the direct respon-sibility of SubcommitteeE44.09 on Photovoltaic Electric Power Conversion.Current edition approved March 1, 2015. Published April 2015. Originallyapproved in 2002. Last
13、 previous edition approved in 2010 as E223610. DOI:10.1520/E2236-10R15.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe AST
14、M website.3The last approved version of this historical standard is referenced onwww.astm.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1C = reference cell calibration constant under the refer-ence spectrum, Am2W1Eo= total irradi
15、ance of reporting conditions, Wm2ES() = source spectral irradiance, Wm2nm1orWm2m1ER() = reference spectral irradiance, Wm2nm1orWm2m1FF = fill factor, dimensionlessi = subscript index associated with an individual com-ponent cellIo= current of test device under the reference spectrum,AI = current of
16、test device under the source spectrum, AIsc= short-circuit current, AIR= short-circuit current of reference cell under thesource spectrum, AM = spectral mismatch parameter, dimensionlessn = number of component cells in the multijunctiondevicePmax= maximum power, WQ() = quantum efficiency, dimensionl
17、essR() = spectral response, AW1RT() = test device spectral response, AW1RR() = reference cell spectral response, AW1T = temperature, CVoc= open-circuit voltage, VVb= voltage applied by dc bias source, VZ = current balance, dimensionless = wavelength, nm or m4. Significance and Use4.1 In a series-con
18、nected multijunction PV device, theincident total and spectral irradiance determines which com-ponent cell will generate the smallest photocurrent and thuslimit the current through the entire series-connected device.This current-limiting behavior also affects the fill factor of thedevice. Because of
19、 this, special techniques are needed tomeasure the correct I-Vcharacteristics of multijunction devicesunder the desired reporting conditions (see Test MethodsE1036).4.2 These test methods use a numerical parameter called thecurrent balance which is a measure of how well the testconditions replicate
20、the desired reporting conditions. When thecurrent balance deviates from unity by more than 0.03, theuncertainty of the measurement may be increased.4.3 The effects of current limiting in individual componentcells can cause problems for I-V curve translations to differenttemperature and irradiance co
21、nditions, such as the translationsrecommended in Test Methods E1036. For example, if adifferent component cell becomes the limiting cell as theirradiance is varied, a discontinuity in the current versusirradiance characteristic may be observed. For this reason, it isrecommended that I-V characterist
22、ics of multijunction devicesbe measured at temperature and irradiance conditions close tothe desired reporting conditions.4.4 Some multijunction devices have more than two termi-nals which allow electrical connections to each componentcell. In these cases, the special techniques for spectral respons
23、emeasurements are not needed because the component cells canbe measured individually. However, these I-V techniques arestill needed if the device is intended to be operated as atwo-terminal device.4.5 Using these test methods, the spectral response istypically measured while the individual component
24、 cell undertest is illuminated at levels that are less than Eo. Nonlinearityof the spectral response may cause the measured results todiffer from the spectral response at the illumination levels ofactual use conditions.5. Summary of Test Methods5.1 Spectral response measurements of the device under
25、testare accomplished using light- and voltage-biasing techniquesof each component cell, followed by determination of thespectral response according to Test Methods E1021.5.2 If a spectrally adjustable solar simulator is available (see6.1.1) the electrical performance measurements use an iterativepro
26、cess of adjusting the incident spectral irradiance until theoperating conditions are close to the desired reporting condi-tions is used. This adjustment modifies a quantity known as thecurrent balance. The I-V characteristics are then measuredaccording to Test Methods E948 or E1036. Appendix X1conta
27、ins a derivation and discussion of current balance.5.3 For the case of light sources where the spectral irradi-ance cannot be changed, such as outdoors or if a spectrallyadjustable solar simulator is not available, the I-V characteris-tics are measured according to Test Methods E948 or E1036.However
28、, the current balance in each component cell must alsobe determined and reported.6. Apparatus6.1 In addition to the apparatus required for Test MethodsE948, E973, E1021, E1036, and G138, these test methods referto the following apparatus.6.1.1 spectrally adjustable Solar SimulatorA solar simu-lator
29、that meets the requirements of Specification E927 andwhich has the additional capability of allowing differentwavelength regions of its spectral irradiance to be indepen-dently adjusted. This may be accomplished by severalmethods, such as a multisource simulator with independentsources for different
30、 regions, or a multiple filter simulator.6.1.1.1 Ideally, the adjustable wavelength ranges of thespectrally adjustable solar simulator should correspond to thespectral response ranges of each component cell in the multi-junction device to be tested.6.1.2 Reference CellsPhotovoltaic reference cells (
31、seeSpecification E1040), calibrated according to Test MethodsE1125 or E1362, are used to measure source irradiance in thewavelength regions that correspond to each component cell inthe multijunction device to be tested. For best results, thespectral responses of the reference cells should be similar
32、 to thespectral responses of the corresponding component cells.6.1.3 Bias Light SourceAdc bias light as specified by TestMethods E1021, that is equipped with appropriate spectralfilters to block wavelength regions corresponding to theexpected spectral response range of the individual componentcell b
33、eing tested.E2236 10 (2015)26.1.3.1 Acceptable alternatives to filtered light sources arecontinuous lasers that emit at single wavelengths in the spectralresponse ranges of each component cell. Ideally, the selectedlaser wavelengths should not illuminate regions where thespectral responses of any tw
34、o component cells overlap.6.1.4 Bias Voltage SourceA variable dc power supplycapable of providing a voltage equal to the open-circuit voltageof the multijunction device to be tested, and compatible withthe synchronous detection instrumentation of Test MethodsE1021.7. Procedure7.1 Spectral Response:7
35、.1.1 Place the device under test in the spectral response testfixture.7.1.2 Select the component cell to be measured.7.1.3 Apply light bias to component cells not being mea-sured using the bias light source:7.1.3.1 Choose spectral filters whose spectral transmittance,when combined, corresponds to th
36、e spectral response of thecomponent cell or cells not being measured. Install the spectralfilters in front of the bias light source.7.1.3.2 If lasers are used, turn on the lasers that emitwavelengths corresponding to the component cell or cells notbeing measured.7.1.3.3 Ideally, the illumination on
37、the component cell beingmeasured should be at Eoand the component cells not beingmeasured should be illuminated at higher levels. Practically,the component cell to be measured should have someillumination, as device spectral responsivities can be a functionof the illumination level.7.1.3.4 Turn on t
38、he bias light source and illuminate, as aminimum, the region where the monochromatic beam illumi-nates the test device.7.1.4 Measure the Vocof the test device.7.1.5 Calculate the bias voltage to use during the test:7.1.5.1 For devices with component cells that contributesimilar voltages, calculate t
39、he bias voltage according to Eq 1.Vb5n 2 1nVoc. (1)7.1.5.2 For devices with component cells contributing sub-stantially different voltages, calculate the bias voltage as thesum of the expected voltage contributions from the componentcells not being measured.7.1.6 Set the Vbon the bias voltage source
40、.7.1.7 Connect the test device to the ac measurement instru-mentation.7.1.8 Maximize the ac signal from the component cell undertest using a wavelength at which it is expected to respond:7.1.8.1 Set the monochromatic light source to a wavelengthin the expected spectral response region of the compone
41、nt cellto be measured.7.1.8.2 Adjust the bias light intensity to saturate or maxi-mize the test device signal.7.1.9 Minimize the test device signal at wavelengths wherethe component cells not being measured are expected torespond:7.1.9.1 Set the monochromatic light source for a wavelengthin the expe
42、cted spectral response region of the component cellnot being measured.7.1.9.2 Minimize or zero the test device signal by adjustingthe bias light intensity.7.1.9.3 Repeat 7.1.9.1 and 7.1.9.2 for additional componentcells not being measured, if any.7.1.10 As in 7.1.8 and 7.1.9, adjust Vbto further max
43、imizethe signal in 7.1.8 and further minimize the signal in 7.1.9.7.1.11 Select light bias and voltage bias levels that bothmaximize the signal in 7.1.8 and minimize the signal in 7.1.9.The signal in 7.1.9 should correspond to a quantum efficiency,Q(), that is less than 0.01 in wavelength regions wh
44、ere thecomponent cell being measured is known to have no response.7.1.12 It may be necessary to adjust the bias light source in7.1.3 to obtain a light bias condition that satisfies 7.1.11.7.1.13 Measure the relative spectral response of the compo-nent cell being tested according to Test Methods E102
45、1.7.1.14 Repeat 7.1.2 7.1.13 for each component cell of themultijunction device under test.7.2 Electrical Performance, spectrally adjustable SolarSimulator:7.2.1 Adjust the total irradiance of the spectrally adjustablesolar simulator to a level close to the desired reportingconditions using a refere
46、nce cell or previous experience (thisinitial irradiance level is not critical).7.2.2 Measure the spectral irradiance of the spectrally ad-justable solar simulator with a spectroradiometer calibratedaccording to Test Method G138.7.2.3 Calculate the spectral mismatch parameter, Mi, foreach component c
47、ell in the multijunction device under testusing the spectral responses obtained in 7.1, the reference cellspectral responses, the spectral irradiance measured in 7.2.2,and the desired reference spectral irradiance (such as TablesG173).7.2.4 Measure the Iscof each reference cell under thespectrally a
48、djustable solar simulator, IRi, in the same test planeas the multijunction device under test.7.2.5 Calculate the current balance, Zi, for each componentcell in the multijunction device under test using the followingequation:Zi51MiEOCiIRi(2)7.2.6 If the current balance for each cell is within1.0060.0
49、3, the spectrally adjustable solar simulator is adjustedto within reasonable limits. If not, adjust the spectral irradianceand repeat 7.2.2 7.2.5.7.2.6.1 Ideally, to minimize spectral errors, each currentbalance should be within 1.0060.01, although the number ofiterations required to obtain this degree of balance may beprohibitive.7.2.6.2 It should be noted that for intermediate iterations, itis possible to omit the spectral irradiance measurement of 7.2.2and substitute the spectral irradiance measured for previousiterations, especia
