IEC 62788-1-7:2020

IEC 62788-1-7 ®
Edition 1.0 2020-04
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Measurement procedures for materials used in photovoltaic modules –
Part 1-7: Encapsulants – Test procedure of optical durability

Procédures de mesure des matériaux utilisés dans les modules
photovoltaïques –
Partie 1-7: Encapsulants – Procédure d’essai de la durabilité optique

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IEC 62788-1-7 ®
Edition 1.0 2020-04
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Measurement procedures for materials used in photovoltaic modules –

Part 1-7: Encapsulants – Test procedure of optical durability

Procédures de mesure des matériaux utilisés dans les modules

photovoltaïques –
Partie 1-7: Encapsulants – Procédure d’essai de la durabilité optique

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 27.160 ISBN 978-2-8322-8035-5

– 2 – IEC 62788-1-7:2020 © IEC 2020
CONTENTS
FOREWORD . 3
INTRODUCTION . 5
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 7
4 Principle . 7
5 Apparatus . 7
5.1 Spectrophotometer for transmittance measurements . 7
5.2 Environmental chamber for weathering . 7
6 Test specimens . 8
6.1 Specimen components and general considerations for all material types . 8
6.2 Test specimens for datasheet reporting . 8
6.3 Use of alternate superstrate and substrate materials . 8
6.4 Witness specimens and experimental control . 9
7 Measurement procedure . 9
8 Artificial accelerated weathering . 9
9 Calculation and expression of results . 9
10 Test procedure . 10
11 Pass/fail criteria . 10
12 Test report . 11
Bibliography . 13

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
MEASUREMENT PROCEDURES FOR
MATERIALS USED IN PHOTOVOLTAIC MODULES –

Part 1-7: Encapsulants –
Test procedure of optical durability

FOREWORD
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International Standard IEC 62788-1-7 has been prepared by IEC technical committee 82: Solar
photovoltaic energy systems.
The text of this International Standard is based on the following documents:
FDIS Report on voting
82/1669/FDIS 82/1704/RVD
Full information on the voting for the approval of this International Standard can be found in the
report on voting indicated in the above table.
This document has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts in the IEC 62788 series, published under the general title Measurement
procedures for materials used in photovoltaic modules, can be found on the IEC website.

– 4 – IEC 62788-1-7:2020 © IEC 2020
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to
the specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
INTRODUCTION
IEC 61215-2 (covering module design qualification and type approval) specifies a UV
-2 -2
preconditioning of 54 MJ⋅m (15 kWh⋅m ), which would be encountered after ~40 ideal sunny
days of exposure to the AM1.5G UV spectrum in IEC 60904-3. IEC 61730-2 presently specifies
4x the same UV exposure, i.e., 5 months UV dose. The International PV Quality Assurance
Task Force (PVQAT) leads global efforts to craft quality and reliability standards for solar
energy technologies. These standards will allow stakeholders to quickly assess a solar
photovoltaic (PV) module's performance and ability to withstand weather stresses, thereby
reducing risk and adding confidence for those developing products, designing incentive
programs, and determining private investments. As developed in conjunction with PVQAT, this
part of IEC 62788-1 is intended to supplement module qualification, which typically covers
reliability issues related to infant mortality, i.e., the first months of field use. This part of
IEC 62788-1 may also facilitate the pre-qualification of encapsulation materials using coupon
specimens, because long term weathering is not practical for larger module specimens. This
part of IEC 62788-1 also importantly uses high fidelity UV irradiation (relati
...