Electrical characterization intercomparison of high‐efficiency c‐Si modules within Asian and European laboratories

Abstract

This work presents the results of a high-efficiency (HE) photovoltaic (PV) module roundrobin intercomparison between five Asian and European ISO/IEC 17025 accredited laboratories and one industrial laboratory based in Europe. The scope of the round-robin was to examine the measurements comparability for this PV technology with respect to ISO/IEC 17025 laboratory conformity assessment and also to examine the accuracy of step-like methods towards transient errors against already validated methods. The devices under test were four types of HE c-Si PV modules with efficiencies varying between 16.5% and 19.0%. The results indicate that a satisfactory agreement was achieved with maximum deviations of 1.59% in P max , 1.13% in I sc , and 0.64% in V oc for all devices under test. The weighted standard deviations in P max per device type, which can be seen as a conservative estimate of interlaboratory agreement for HE c-Si PV, ranged within 0.82% to 2.23% (k = 2). The accuracy of step-like methods towards transient errors was evaluated by comparing a second series of results at fixed I sc for each module under test, eliminating the influence of the effective irradiance measurement. This work suggests that the contribution of capacitive errors was in the range (0.47 ± 0.19) % (k = 2). A spectral mismatch sensitivity analysis showed that an accurate measurement of the spectral irradiance and of the involved spectral responsivities together with the punctual correction for the spectral mismatch can reduce the error in the measurement of PV modules performance of about 2% even in the case of c-Si against c-Si and class AAA solar simulators.This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

A European proficiency test on thin‐film tandem photovoltaic devices

“…As mentioned above, the methodology used to assess the participants' results against the reference value was based on the standard ISO/IEC 17043 34 and on previous experience. [21][22][23]25 Figure 3) at the end of the RR, when the DUT returned there, and before any further preconditioning to take it back to a stabilised state. The additional stabilisation brought this DUT to a P max value −10.9% (ES in Figure 3) smaller than the RMPT value, showing a significant change in the electrical performance of the device.…”

“…The RR was organised within the CHEETAH project 33 as a PT for 13 participating laboratories, also building on a failure analysis of the SOPHIA project's RR and on prior experience in interlaboratory comparisons. [21][22][23]25 The reference measurements were independently provided by ESTI, which calibrated all devices at the beginning of the PT (see Section 2.4). The devices were again shipped to ESTI at the end of the RR PT for a final verification and calibration.…”

“…The standard ISO/IEC 17043 34 was taken as guideline for the evaluation of the participants' results, as already done in previous similar exercises for PV. 23,25 As initiator of the RR within the CHEETAH project, Helmholtz-Zentrum Berlin (HZB) acted as the coordinator (but not as the official provider in the sense of ISO/IEC 17043 34 ) of the RR PT, although it was also a PT participant. This double role of one participant is usually avoided in PTs organised by official PT providers for testing laboratories, in order to assure unbiased results assessment.…”

“…In addition, as good practice for measurement and testing laboratories, and even required for calibration laboratories accredited to ISO/IEC 17025, 16 in the last 30 years several interlaboratory comparisons and round-robins have already been organised for SJ PV testing at STC. [17][18][19][20][21][22][23][24][25] The World Photovoltaic Scale (WPVS) itself, which nowadays has become a sort of alias to refer to a solar cell with some standardised package, was in fact established in 1999 as measurement scale for PV starting from a dedicated world-wide intercomparison on calibration of PV cells. [26][27][28] Similar measurement comparisons are less numerous and less geographically wide in the case of MJ PV devices.…”

“…The light-blue-shaded area helps in separating them from the results of the RR PT participants, too. Among the participants, only three laboratories (#4, #5 and #6) agree with the RMPT P max value: the first two directly because they are within the UC band of the RMPT value; the third one because its UC almost intersects the RMPT value and the E n number is 0.87, which represents agreement with the RMPT value (one can refer for example to open-access peerreviewed references23,25,46 for the E n number calculation). The F I G U R E Percentage deviations from ESTI RMPT value for I SC , V OC , P max and FF of RR82 (μc-Si).…”