IEC 62788-1-6:2017

Measurement procedures for materials used in photovoltaic modules - Part 1-6: Encapsulants - Test methods for determining the degree of cure in Ethylene-Vinyl Acetate

IEC 62788-1-6:2017 defines the terminology, test equipment, test environment, specimen preparation, test procedures, and test report for measuring the degree of cure of Ethylene-Vinyl Acetate (EVA) encapsulation sheet used in photovoltaic (PV) modules. The differential scanning calorimetry (both residual enthalpy and melt/freeze protocols) and gel content methods are included herein. This procedure can be used by material- or module-manufacturers to verify that the cross-linking additive is present and is active. The procedure can also be used to verify the module manufacturing (lamination) process for the purposes of quality- and process-control. The procedure can also be used to assess the uniformity of the EVA formulation within a roll as well as to compare variation of the EVA formulation from roll to roll.

Procédures de mesure des matériaux utilisés dans les modules photovoltaïques - Partie 1-6: Encapsulants - Méthodes d'essai pour déterminer le degré de durcissement dans l'éthylène-acétate de vinyle

L’IEC 62788-1-6:2017 définit la terminologie, l'équipement d'essai, l'environnement d'essai, la préparation des éprouvettes, les procédures d'essai et le rapport d'essai pour le mesurage du degré de durcissement de la couche d'encapsulation en éthylène-acétate de vinyle (EVA) utilisée dans les modules photovoltaïques (PV). Les méthodes de l'analyse calorimétrique différentielle à balayage (protocoles d'enthalpie résiduelle et de fusion/gel) et du taux de gel sont incluses dans le présent document. Cette procédure peut être utilisée par les fabricants de matériaux ou de modules pour s'assurer que l'additif de réticulation est présent et actif. La procédure peut également être utilisée pour vérifier le procédé de fabrication (stratification) du module à des fins de contrôle de la qualité et des processus. Elle peut en outre être utilisée pour évaluer l'uniformité de la formulation d’EVA dans un rouleau et comparer les différences de formulation d’EVA d'un rouleau à l'autre.

General Information

• Status: Published
• Publication Date: 25-May-2020
• ICS: 01 - GENERALITIES. TERMINOLOGY. STANDARDIZATION. DOCUMENTATION
• ICS: 27.160 - Solar energy engineering
• Technical Committee: TC 82 - Solar photovoltaic energy systems
• Drafting Committee: WG 2 - TC 82/WG 2
• Current Stage: PPUB - Publication issued
• Start Date: 04-Feb-2017
• Completion Date: 27-Jan-2017

Relations

• Amended By: IEC 62788-1-6:2017/AMD1:2020 - Amendment 1 - Measurement procedures for materials used in photovoltaic modules - Part 1-6: Encapsulants - Test methods for determining the degree of cure in Ethylene-Vinyl Acetate
• Effective Date: 05-Sep-2023

Standards Content (Sample)

IEC 62788-1-6 ®
Edition 1.0 2017-01
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Measurement procedures for materials used in photovoltaic modules –
Part 1-6: Encapsulants – Test methods for determining the degree of cure in
Ethylene-Vinyl Acetate
Procédures de mesure des matériaux utilisés dans les modules
photovoltaïques –
Partie 1-6: Encapsulants – Méthodes d'essai pour déterminer le degré de
durcissement dans l'éthylène-acétate de vinyle

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form
or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from
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IEC 62788-1-6 ®
Edition 1.0 2017-01
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Measurement procedures for materials used in photovoltaic modules –

Part 1-6: Encapsulants – Test methods for determining the degree of cure in

Ethylene-Vinyl Acetate
Procédures de mesure des matériaux utilisés dans les modules

photovoltaïques –
Partie 1-6: Encapsulants – Méthodes d'essai pour déterminer le degré de

durcissement dans l'éthylène-acétate de vinyle

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 27.160 ISBN 978-2-8322-3857-8

– 2 – IEC 62788-1-6:2017 © IEC 2017
CONTENTS
FOREWORD . 4
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 7
4 Principle . 7
5 DSC secondary method . 8
5.1 Instrument and equipment for the secondary method . 8
5.1.1 General . 8
5.1.2 Electronic balance . 8
5.1.3 Differential scanning calorimeter . 8
5.1.4 Instrument calibration . 8
5.2 Specimen preparation for the secondary method. 9
5.2.1 Sampling and storage . 9
5.2.2 Preparation procedures . 9
5.3 Test requirements for the secondary method . 9
5.3.1 Environment requirements . 9
5.3.2 Parameter settings (residual enthalpy method) . 10
5.3.3 Parameter settings (melt/freeze method) . 10
5.3.4 Parameter settings (combined enthalpy and melt/freeze method) . 10
5.4 Test procedure for the secondary method . 11
5.5 Calculation and expression of the results for the secondary method . 11
5.5.1 Enthalpy method . 11
5.5.2 Melt/freeze method . 12
5.6 Uncertainty of measurements for the secondary method . 16
6 The primary method . 16
6.1 Principle for the primary method . 16
6.2 Instrument and equipment for the primary method . 17
6.2.1 Electronic balance . 17
6.2.2 Soxhlet extractor . 17
6.2.3 Thimble . 17
6.2.4 Heating apparatus . 17
6.2.5 Handling apparatus. 18
6.2.6 Solvent . 18
6.3 Specimen preparation for the primary method . 18
6.3.1 Sampling and storage . 18
6.3.2 Preparation procedures . 18
6.4 Test requirements for the primary method – Environment requirements . 19
6.5 Test procedure for the primary method . 19
6.6 Calculation and expression of the results for the primary method . 19
7 Test report . 19
Annex A (informative) Limitations of the primary and secondary measurement methods
...................................................................................................................................... 21
Bibliography . 23

Figure 1 – Example result for the DSC residual enthalpy method . 12

Figure 2 – Location of temperatures and temperature ranges used in the melt/freeze DSC
method . 13
Figure 3 – Example of the temperature bounds applied for an automated software
integration algorithm . 14
Figure 4 – Representation of the measurement profile for an EVA test specimen . 16

Table 1 – Summary of the results for the example measurements shown in Figure 2 . 14

– 4 – IEC 62788-1-6:2017 © IEC 2017
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
MEASUREMENT PROCEDURES FOR MATERIALS USED
IN PHOTOVOLTAIC MODULES –
Part 1-6: Encapsulants – Test methods for determining
the degree of cure in Ethylene-Vinyl Acetate

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international
co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and in
addition to other activities, IEC publishes International Standards, Technical Specifications, Technical Reports,
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Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretat
...

IEC 62788-1-6 ®
Edition 1.1 2020-05
CONSOLIDATED VERSION
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Measurement procedures for materials used in photovoltaic modules –
Part 1-6: Encapsulants – Test methods for determining the degree of cure
in Ethylene-Vinyl Acetate
Procédures de mesure des matériaux utilisés dans les modules
photovoltaïques –
Partie 1-6: Encapsulants – Méthodes d'essai pour déterminer le degré
de durcissement dans l'éthylène-acétate de vinyle

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form
or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from
either IEC or IEC's member National Committee in the country of the requester. If you have any questions about IEC
copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or
your local IEC member National Committee for further information.

Droits de reproduction réservés. Sauf indication contraire, aucune partie de cette publication ne peut être reproduite
ni utilisée sous quelque forme que ce soit et par aucun procédé, électronique ou mécanique, y compris la photocopie
et les microfilms, sans l'accord écrit de l'IEC ou du Comité national de l'IEC du pays du demandeur. Si vous avez des
questions sur le copyright de l'IEC ou si vous désirez obtenir des droits supplémentaires sur cette publication, utilisez
les coordonnées ci-après ou contactez le Comité national de l'IEC de votre pays de résidence.

IEC Central Office Tel.: [phone]
3, rue de Varembé [e-mail]
CH-1211 Geneva 20 www.iec.ch
Switzerland
About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.

About IEC publications
The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the
latest edition, a corrigendum or an amendment might have been published.

IEC publications search - webstore.iec.ch/advsearchform Electropedia - www.electropedia.org
The advanced search enables to find IEC publications by a The world's leading online dictionary on electrotechnology,
variety of criteria (reference number, text, technical containing more than 22 000 terminological entries in English
committee,…). It also gives information on projects, replaced and French, with equivalent terms in 16 additional languages.
and withdrawn publications. Also known as the International Electrotechnical Vocabulary

(IEV) online.
IEC Just Published - webstore.iec.ch/justpublished
Stay up to date on all new IEC publications. Just Published IEC Glossary - std.iec.ch/glossary
details all new publications released. Available online and 67 000 electrotechnical terminology entries in English and
once a month by email. French extracted from the Terms and definitions clause of
IEC publications issued between 2002 and 2015. Some
IEC Customer Service Centre - webstore.iec.ch/csc entries have been collected from earlier publications of IEC
If you wish to give us your feedback on this publication or TC 37, 77, 86 and CISPR.

need further assistance, please contact the Customer Service

Centre: [e-mail].
A propos de l'IEC
La Commission Electrotechnique Internationale (IEC) est la première organisation mondiale qui élabore et publie des
Normes internationales pour tout ce qui a trait à l'électricité, à l'électronique et aux technologies apparentées.

A propos des publications IEC
Le contenu technique des publications IEC est constamment revu. Veuillez vous assurer que vous possédez l’édition la
plus récente, un corrigendum ou amendement peut avoir été publié.

Recherche de publications IEC - Electropedia - www.electropedia.org
webstore.iec.ch/advsearchform Le premier dictionnaire d'électrotechnologie en ligne au
La recherche avancée permet de trouver des publications IEC monde, avec plus de 22 000 articles terminologiques en
en utilisant différents critères (numéro de référence, texte, anglais et en français, ainsi que les termes équivalents dans
comité d’études,…). Elle donne aussi des informations sur les 16 langues additionnelles. Egalement appelé Vocabulaire
projets et les publications remplacées ou retirées. Electrotechnique International (IEV) en ligne.

IEC Just Published - webstore.iec.ch/justpublished Glossaire IEC - std.iec.ch/glossary
Restez informé sur les nouvelles publications IEC. Just 67 000 entrées terminologiques électrotechniques, en anglais
Published détaille les nouvelles publications parues. et en français, extraites des articles Termes et définitions des
Disponible en ligne et une fois par mois par email. publications IEC parues entre 2002 et 2015. Plus certaines
entrées antérieures extraites des publications des CE 37, 77,
Service Clients - webstore.iec.ch/csc 86 et CISPR de l'IEC.

Si vous désirez nous donner des commentaires sur cette
publication ou si vous avez des questions contactez-nous:
[e-mail].
IEC 62788-1-6 ®
Edition 1.1 2020-05
CONSOLIDATED VERSION
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Measurement procedures for materials used in photovoltaic modules –

Part 1-6: Encapsulants – Test methods for determining the degree of cure

in Ethylene-Vinyl Acetate
Procédures de mesure des matériaux utilisés dans les modules

photovoltaïques –
Partie 1-6: Encapsulants – Méthodes d'essai pour déterminer le degré

de durcissement dans l'éthylène-acétate de vinyle

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 27.160 ISBN 978-2-8322-8421-6

IEC 62788-1-6 ®
Edition 1.1 2020-05
REDLINE VERSION
VERSION REDLINE
colour
inside
Measurement procedures for materials used in photovoltaic modules –
Part 1-6: Encapsulants – Test methods for determining the degree of cure
in Ethylene-Vinyl Acetate
Procédures de mesure des matériaux utilisés dans les modules
photovoltaïques –
Partie 1-6: Encapsulants – Méthodes d'essai pour déterminer le degré
de durcissement dans l'éthylène-acétate de vinyle

– 2 – IEC 62788-1-6:2017+AMD1:2020 CSV
© IEC 2020
CONTENTS
FOREWORD . 4
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 7
4 Principle . 8
5 DSC secondary method . 8
5.1 Instrument and equipment for the secondary method . 8
5.1.1 General . 8
5.1.2 Electronic balance . 8
5.1.3 Differential scanning calorimeter . 8
5.1.4 Instrument calibration . 9
5.2 Specimen preparation for the secondary method. 9
5.2.1 Sampling and storage . 9
5.2.2 Preparation procedures . 9
5.3 Test requirements for the secondary method . 10
5.3.1 Environment requirements . 10
5.3.2 Parameter settings (residual enthalpy method) . 10
5.3.3 Parameter settings (melt/freeze method) . 10
5.3.4 Parameter settings (combined enthalpy and melt/freeze method) . 10
5.4 Test procedure for the secondary method . 11
5.5 Calculation and expression of the results for the secondary method . 11
5.5.1 Enthalpy method . 11
5.5.2 Melt/freeze method . 12
5.6 Uncertainty of measurements for the secondary method . 16
6 The primary method . 16
6.1 Principle for the primary method . 16
6.2 Instrument and equipment for the primary method . 17
6.2.1 Electronic balance . 17
6.2.2 Soxhlet extractor . 17
6.2.3 Thimble . 17
6.2.4 Heating apparatus . 17
6.2.5 Handling apparatus. 18
6.2.6 Solvent . 18
6.3 Specimen preparation for the primary method . 18
6.3.1 Sampling and storage . 18
6.3.2 Preparation procedures . 18
6.4 Test requirements for the primary method – Environment requirements . 19
6.5 Test procedure for the primary method . 19
6.6 Calculation and expression of the results for the primary method . 19
7 Test report . 19
8 Indentation secondary method . 20
8.1 General . 20
8.2 Principle . 21
8.3 Instrument and equipment for the indentation method . 21
8.4 Instrument calibration . 22

© IEC 2020
8.5 Correlation of the degree of cure. 22
8.6 Specimen preparation for the indentation method . 22
8.7 Test procedure for the indentation method . 23
Annex A (informative) Limitations of the primary and secondary measurement
methods . 24
Bibliography . 26

Figure 1 – Example result for the DSC residual enthalpy method . 12
Figure 2 – Location of temperatures and temperature ranges used in the melt/freeze DSC

method . 13
Figure 3 – Example of the temperature bounds applied for an automated software
integration algorithm . 15
Figure 4 – Representation of the measurement profile for an EVA test specimen . 16
Figure 5 – Example of the correlation applied between G (indentation) and G (gel
i %
content) . 22

Table 1 – Summary of the results for the example measurements shown in Figure 2 . 14

– 4 – IEC 62788-1-6:2017+AMD1:2020 CSV
© IEC 2020
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
MEASUREMENT PROCEDURES FOR MATERIALS USED
IN PHOTOVOLTAIC MODULES –
Part 1-6: Encapsulants – Test methods for determining
the degree of cure in Ethylene-Vinyl Acetate

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international
co-operation on all questions concerning standardization in the electrical and electronic fields. To this end
...