Photovoltaic (PV) modules - Qualifying guidelines for increased hail resistance

IEC TS 63397:2022 defines additional testing requirements for modules deployed under applications or in environments where PV modules are likely to be exposed to the impact of hailstones leading to higher stress beyond the scope of the IEC 61215 series. This document aims to assist in the selection of modules for deployment in specific regions that have a higher risk of hail damage and to provide tools for improving module design.
The contents of the corrigendum of July 2023 have been included in this copy.

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PPUB - Publication issued
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IEC TS 63397:2022 - Photovoltaic (PV) modules - Qualifying guidelines for increased hail resistance Released:12/14/2022
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IEC TS 63397 ®
Edition 1.0 2022-12
Photovoltaic (PV) modules – Qualifying guidelines for increased hail resistance
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IEC TS 63397 ®
Edition 1.0 2022-12
Photovoltaic (PV) modules – Qualifying guidelines for increased hail resistance

ICS 27.160 ISBN 978-2-8322-6194-1

– 2 – IEC TS 63397:2022 © IEC 2022
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 8
4 Number and selection of test samples . 8
5 Test procedures . 8
5.1 General . 8
5.2 Visual inspection (MQT 01) . 8
5.3 Initial stabilization (MQT 19.1) . 8
5.4 Performance at STC (MQT 06.1) . 8
5.5 Performance at low irradiance (MQT 07) . 9
5.6 Insulation test (MQT 03) . 9
5.7 Wet leakage current test (MQT 15) . 9
5.8 Electroluminescence imaging . 9
5.9 Damp heat test (MQT 13) . 9
5.10 Hail test (HMQT 17) . 9
5.10.1 General . 9
5.10.2 Purpose . 9
5.10.3 Apparatus . 9
5.10.4 Procedure . 11
5.10.5 Final measurement . 12
5.10.6 Requirements . 12
5.11 Cyclic (dynamic) mechanical load test (MQT 20) . 13
5.12 Thermal cycling test (MQT 11) . 13
5.13 Humidity-freeze test (MQT 12) . 14
5.14 Final stabilization test (MQT 19.2) . 14
5.15 Requirements . 14
6 Report . 16
Annex A (informative) Hail maps . 18
Bibliography . 19

Figure 1 – Hail test equipment . 10
Figure 2 – Hail test example impact locations for wafer/cell based technologies and for
monolithic thin film technologies . 13
Figure 3 – Test flow . 15
Figure A.1 – Hailstorm map: Global . 18

Table 1 – Ice-ball masses and kinetic energy . 11
Table 2 – Impact locations . 12
Table 3 – Example of power loss reporting. 16
Table 4 – Schematic example of electroluminescence images prior and post stress
tests . 17


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IEC TS 63397 has been prepared by IEC technical committee 82: Solar photovoltaic energy
systems. It is a Technical Specification.
The text of this Technical Specification is based on the following documents:
Draft Report on voting
82/2062/DTS 82/2090/RVDTS
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
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– 4 – IEC TS 63397:2022 © IEC 2022
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The contents of the corrigendum 1 (2023-07) have been included in this copy.

The hail test (MQT 17) of IEC 61215-2:2021, 4.17 examines PV modules for minimum hail
resistance by using spherical ice balls of a minimum diameter of 25 mm, or optionally larger.
The requirements after the test, as specified in IEC 61215-2, are:
a) no intermittent open-circuit fault detected during the test,
b) no evidence of major visual defects,
c) wet leakage current meeting the same requirements as for the initial measurements and the
power loss requirement of (Gate No. 2) IEC 61215-1:2021, 7.2.3.
The hail test (MQT 17) may cause visible damage detectable by MQT 01 as well as invisible
internal damage not detectable by MQT 01. Such invisible damage may also only be detected
by Gate No. 2 (power loss measurement after stress tests) if the damage is relatively large.
The IEC 61215 series [1] lays down requirements for the design qualification and type approval
of terrestrial photovoltaic modules suitable for long-term operation in open-air climates. It is
however not written with the intent to detect medium to long term performance losses caused
by hail to internal parts not visible to the naked eye. Such internal damages may be micro-cracks
of cells which over time can be propagated by other mechanical and thermo-mechanical
environmental stresses not addressed by the test flow of IEC 61215-1:2021, Figure 2.
The hail test (MQT 17) of IEC 61215-2:2021, 4.17 is sufficient for the generic design
qualification and type approval for applications

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