IEC TS 62788-6-3:2022

IEC TS 62788-6-3 ®
Edition 1.0 2022-08
TECHNICAL
SPECIFICATION
colour
inside
Measurement procedures for materials used in photovoltaic modules –
Part 6-3: Adhesion testing for PV module laminates using the single cantilevered
beam (SCB) method
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.

IEC Secretariat Tel.: +41 22 919 02 11
3, rue de Varembé info@iec.ch
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 IEC Products & Services Portal - products.iec.ch
The advanced search enables to find IEC publications by a Discover our powerful search engine and read freely all the
variety of criteria (reference number, text, technical publications previews. With a subscription you will always have
committee, …). It also gives information on projects, replaced access to up to date content tailored to your needs.
and withdrawn publications.
Electropedia - www.electropedia.org
IEC Just Published - webstore.iec.ch/justpublished
The world's leading online dictionary on electrotechnology,
Stay up to date on all new IEC publications. Just Published
containing more than 22 300 terminological entries in English
details all new publications released. Available online and once
and French, with equivalent terms in 19 additional languages.
a month by email.
Also known as the International Electrotechnical Vocabulary

(IEV) online.
IEC Customer Service Centre - webstore.iec.ch/csc

If you wish to give us your feedback on this publication or need
further assistance, please contact the Customer Service
Centre: sales@iec.ch.
IEC TS 62788-6-3 ®
Edition 1.0 2022-08
TECHNICAL
SPECIFICATION
colour
inside
Measurement procedures for materials used in photovoltaic modules –

Part 6-3: Adhesion testing for PV module laminates using the single

cantilevered beam (SCB) method

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 27.160 ISBN 978-2-8322-5561-2

– 2 – IEC TS 62788-6-3:2022 © IEC 2022
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 7
4 Apparatus . 9
4.1 Load frame . 9
4.2 Loading tab . 10
5 Width-tapered cantilever beam . 10
5.1 General . 10
5.2 Beam design . 11
5.3 Beam selection . 11
6 Test method . 12
6.1 Specimen preparation . 12
6.2 Measurement procedure . 12
6.3 Analysis . 14
6.3.1 Critical adhesion energy, G . 14
c
7 Report . 15
Annex A (informative) Summary of background theory, and how this method can be
generalized . 16
A.1 Background theory . 16
A.2 Beam materials . 17
Annex B (informative) Guidance for specific use cases . 18
B.1 General . 18
B.2 Adhesion test coupons . 18
B.2.1 Backsheet / encapsulant adhesion . 18
B.2.2 Backsheet interlayer adhesion . 18
B.2.3 Glass/encapsulant adhesion . 19
B.2.4 Adhesion between different encapsulants . 19
B.2.5 Cell/encapsulant (coupons) . 20
B.3 Modules . 20
B.3.1 General . 20
B.3.2 Targeting a specific interface in a module . 20
Annex C (informative) Reference engineering diagrams for loading tab and beam . 23
Annex D (normative) Using a reference compliance curve to calculate G . 26
c
D.1 General . 26
D.2 Procedure . 26
D.2.1 Beam compliance measurement . 26
D.2.2 Definition of empirical parameters . 27
D.2.3 Validation of reference parameters . 27
D.2.4 Generating a custom set of α, β and γ parameters . 28
D.2.5 Calculation of crack length a for adhesion specimens . 29
i
Annex E (informative) Methods for measurement of final debond length a . 30
f
E.1 General . 30
E.2 Aluminum foil method. 30

E.3 Light method . 30
E.4 Pull-apart method . 30
Bibliography . 32

Figure 1 – Diagram of the loading connection using a clevis grip . 9
Figure 2 – Schematic of load frame with a) a platen for securing test coupon, and b)
modified to sit on top of a PV module . 10
Figure 3 – Photos of the loading tab alone, and attached to the beam . 10
Figure 4 – Width-tapered beam . 11
Figure 5 – Typical width-tapered cantilever beam load/displacement curve . 13
Figure 6 – Example of an a measurement on glass/encapsulant/cell specimens . 14
f
Figure B.1 – Top view of backsheet and encapsulant beam coupons . 21
Figure B.2 – Cross-sectional view of backsheet and encapsulant beam coupons . 22
Figure C.1 – Schematics of loading tab . 24
Figure C.2 – Schematics of beam . 25
Figure D.1 – Photo of a beam prior to start of the calibration measurement . 26
Figure D.2 – Photo of a beam at the end of the calibration measurement . 27
Figure D.3 – Plot used for generating beam calibration curves with the empirical fits
according to Formula (D.2) using values from Table D.1 . 29
Figure E.1 – Illustration of debond length measurement with a cohesive zone . 31

Table 1 – Typical adhesion strengths . 12
Table D.1 – Reference empirical fit parameters . 27
Table D.2 – Example read points for fit evaluation . 28

– 4 – IEC TS 62788-6-3:2022 © IEC 2022
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
MEASUREMENT PROCEDURES FOR MATERIALS
USED IN PHOTOVOLTAIC MODULES –

Part 6-3: Adhesion testing for PV module laminates
using the single cantilevered beam (SCB) method

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,
Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC Publication(s)”). Their
preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with
may participate in this preparatory work. International, governmental and non-governmental organizations liaising
with the IEC also participate in this preparation. IEC collaborates closely with the International Organization for
Standardization (ISO) in accordance with conditions determined by agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
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
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence between
any IEC Publication and the corresponding national or regional publication shall be clearly indicated in the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of patent
...