Concentrator photovoltaic (CPV) solar cells and cell-on-carrier (COC) assemblies - Reliability qualification

This document specifies the minimum requirements for the qualification of concentrator
photovoltaic (CPV) cells and Cell on Carrier (CoC) assemblies for incorporation into CPV
receivers, modules and systems.
The object of this qualification standard is to determine the optoelectronic, mechanical, thermal,
and processing characteristics of CPV cells and CoCs to show that they are capable of
withstanding assembly processes and CPV application environments. The qualification tests of
this document are designed to demonstrate that cells or CoCs are suitable for typical assembly
processes, and when properly assembled, are capable of passing IEC 62108.
This document defines qualification testing for two levels of concentrator photovoltaic device
assembly:
a) cell, or bare cell; and
b) cell on carrier (CoC).
NOTE Note that a variety of alternate names are used within the industry, such as solar cell assembly, receiver,
etc.

Konzentrator-Photovoltaik(CPV)-Solarzellen und -Anordnungen von Solarzellen auf Trägern (CoC) - Qualifikation

Cellules solaires photovoltaïques à concentration (PVC) et ensembles de cellules sur support (CoC) - Qualification

IEC 62787:2021 spécifie les exigences minimales relatives à la qualification des cellules photovoltaïques à concentration (CPV) et des assemblages de cellules sur support (CoC) pour intégration dans les récepteurs, modules et systèmes CPV.
La présente norme de qualification a pour objet de déterminer les caractéristiques optoélectroniques, mécaniques, thermiques et de traitement des cellules CPV et des CoC afin de montrer qu’elles sont capables de résister aux processus de l’assemblage et aux environnements d’application des CPV. Les essais de qualification du présent document visent à démontrer que les cellules ou les CoC sont adaptées à des processus d’assemblage classiques, et qu’elles sont capables de satisfaire à l’IEC 62108 si elles sont correctement assemblées.
Le présent document définit les essais de qualification pour deux niveaux d’un ensemble de dispositifs photovoltaïques à concentration:
a) cellule (ou cellule nue), et
b) cellule sur support (CoC).

Koncentratorske fotonapetostne (CPV) sončne celice in sestavi celic na nosilcu (CoC) - Opredelitev zanesljivosti

General Information

Status
Published
Publication Date
03-May-2021
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
06-Apr-2021
Due Date
11-Jun-2021
Completion Date
04-May-2021

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SLOVENSKI STANDARD
SIST EN IEC 62787:2021
01-junij-2021
Koncentratorske fotonapetostne (CPV) sončne celice in sestavi celic na nosilcu
(CoC) - Opredelitev zanesljivosti
Concentrator photovoltaic (CPV) solar cells and cell-on-carrier (COC) assemblies -
Reliability qualification
Ta slovenski standard je istoveten z: EN IEC 62787:2021
ICS:
27.160 Sončna energija Solar energy engineering
SIST EN IEC 62787:2021 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN IEC 62787:2021

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SIST EN IEC 62787:2021


EUROPEAN STANDARD EN IEC 62787

NORME EUROPÉENNE

EUROPÄISCHE NORM
March 2021
ICS 27.160

English Version
Concentrator photovoltaic (CPV) solar cells and cell on carrier
(CoC) assemblies - Qualification
(IEC 62787:2021)
Cellules solaires photovoltaïques à concentration (PVC) et Konzentrator-Photovoltaik(CPV)- Solarzellen und -
ensembles de cellules sur support (CoC) - Qualification Anordnungen von Solarzellen auf Trägern (CoC)
(IEC 62787:2021) (IEC 62787:2021)
This European Standard was approved by CENELEC on 2021-03-10. CENELEC members are bound to comply with the CEN/CENELEC
Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.
Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC
Management Centre or to any CENELEC member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the
same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,
Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the
Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.


European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2021 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
 Ref. No. EN IEC 62787:2021 E

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SIST EN IEC 62787:2021
EN IEC 62787:2021 (E)
European foreword
The text of document 82/1818/FDIS, future edition 1 of IEC 62787, prepared by IEC/TC 82 "Solar
photovoltaic energy systems" was submitted to the IEC-CENELEC parallel vote and approved by
CENELEC as EN IEC 62787:2021.
The following dates are fixed:
• latest date by which the document has to be implemented at national (dop) 2021-12-10
level by publication of an identical national standard or by endorsement
• latest date by which the national standards conflicting with the (dow) 2024-03-10
document have to be withdrawn
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC shall not be held responsible for identifying any or all such patent rights.
Endorsement notice
The text of the International Standard IEC 62787:2021 was approved by CENELEC as a European
Standard without any modification.
2

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SIST EN IEC 62787:2021
EN IEC 62787:2021 (E)
Annex ZA
(normative)

Normative references to international publications
with their corresponding European publications
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments)
applies.
NOTE 1  Where an International Publication has been modified by common modifications, indicated by (mod),
the relevant EN/HD applies.
NOTE 2  Up-to-date information on the latest versions of the European Standards listed in this annex is available
here: www.cenelec.eu.
Publication Year Title EN/HD Year
IEC 60721-2-1 2013 Classification of environmental conditions EN 60721-2-1 2014
- Part 2-1: Environmental conditions
appearing in nature - Temperature and
humidity
IEC 60749-3 2017 Semiconductor devices - Mechanical and EN 60749-3 2017
climatic test methods - Part 3: External
visual examination
IEC 60749-6 2017 Semiconductor devices - Mechanical and EN 60749-6 2017
climatic test methods - Part 6: Storage at
high temperature
IEC 60749-14 2003 Semiconductor devices - Mechanical and EN 60749-14 2003
climatic test methods - Part 14:
Robustness of terminations (lead
integrity)
IEC 60749-21 2011 Semiconductor devices - Mechanical and EN 60749-21 2011
climatic test methods - Part 21:
Solderability
IEC 60749-22 2002 Semiconductor devices - Mechanical and EN 60749-22 2003
climatic test methods - Part 22: Bond
strength
IEC 60904-1-1 2017 Photovoltaic devices - Part 1-1: EN 60904-1-1 2017
Measurement of current-voltage
characteristics of multi-junction
photovoltaic (PV) devices
IEC 61000-4-2 2008 Electromagnetic compatibility (EMC) - EN 61000-4-2 2009
Part 4-2: Testing and measurement
techniques - Electrostatic discharge
immunity test
3

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SIST EN IEC 62787:2021
EN IEC 62787:2021 (E)
Publication Year Title EN/HD Year
IEC 61193-2 2007 Quality assessment systems - Part 2: EN 61193-2 2007
Selection and use of sampling plans for
inspection of electronic components and
packages
IEC/TS 61836 2016 Solar photovoltaic energy systems - - -
Terms, definitions and symbols
IEC 62108 2016 Concentrator photovoltaic (CPV) EN 62108 2016
modules and assemblies - Design
qualification and type approval
IEC 62137-1-2 2007 Surface mounting technology - EN 62137-1-2 2007
Environmental and endurance test
methods for surface mount solder joint -
Part 1-2: Shear strength test
IEC 62670-1 2013 Photovoltaic concentrators (CPV) - EN 62670-1 2014
Performance testing - Part 1: Standard
conditions
IEC/TS 62789 2014 Photovoltaic concentrator cell - -
documentation
IEC 63202-2 - Photovoltaic cells - Part 2: - -
Electroluminescence image for
crystalline silicon solar cells
ECSS-E-ST-20- 2012 Space engineering - Photovoltaic EN 16603-20-08 2014
08C Rev.1 assemblies and components - Part 7.5.8:
Coating adherence (CA)
MIL.ST-883-K - Test Method Standard - Microcircuits - -
Method 2019.9 Die shear strength

4

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SIST EN IEC 62787:2021




IEC 62787

®


Edition 1.0 2021-02




INTERNATIONAL



STANDARD




NORME


INTERNATIONALE
colour

inside










Concentrator photovoltaic (CPV) solar cells and cell on carrier (CoC) assemblies –

qualification



Cellules solaires photovoltaïques à concentration (PVC) et ensembles de

cellules sur support (CoC) – Qualification















INTERNATIONAL

ELECTROTECHNICAL

COMMISSION


COMMISSION

ELECTROTECHNIQUE


INTERNATIONALE




ICS 27.160 ISBN 978-2-8322-9326-3




Warning! Make sure that you obtained this publication from an authorized distributor.

Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agréé.

® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale

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SIST EN IEC 62787:2021
– 2 – IEC 62787:2021 © IEC 2021
CONTENTS
FOREWORD . 4
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 7
4 Operating environment . 9
5 Sampling . 9
6 Marking . 10
7 Characterization methods for measuring the performance of bare cells and CoCs
subjected to qualification tests . 10
7.1 General . 10
7.2 Light I-V measurement . 10
7.3 Dark I-V measurement . 11
7.3.1 General . 11
7.3.2 Procedure . 11
7.4 Electroluminescence (EL) mapping . 11
7.5 X-ray and Scanning Acoustic Microscope (SAM) . 12
7.6 Visual inspection . 12
7.7 Thermal resistance measurement . 12
8 Pass criteria . 13
9 Documentation and reporting . 20
10 Modifications and requalification . 20
11 Qualification stress tests . 21
11.1 General . 21
11.2 ESD damage threshold . 21
11.2.1 General . 21
11.2.2 Purpose . 21
11.2.3 Procedure . 22
11.2.4 Requirements . 22
11.3 Front and back metal adhesion . 22
11.3.1 Purpose . 22
11.3.2 Procedure . 22
11.3.3 Requirements . 22
11.4 High-temperature storage . 22
11.4.1 Purpose . 22
11.4.2 Procedure . 22
11.4.3 Requirements . 23
11.5 Thermal cycling. 23
11.5.1 Purpose . 23
11.5.2 Procedure . 23
11.5.3 Requirements . 24
11.6 High temperature with current injection . 24
11.6.1 Purpose . 24
11.6.2 Procedure . 25
11.6.3 Requirements . 25
11.7 Low level light biased damp heat . 25
11.7.1 Purpose . 25

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SIST EN IEC 62787:2021
IEC 62787:2021 © IEC 2021 – 3 –
11.7.2 Procedure . 25
11.7.3 Requirements . 25
11.8 Solderability . 26
11.8.1 Purpose . 26
11.8.2 Procedure . 26
11.8.3 Requirements . 27
11.9 Illumination . 27
11.9.1 Purpose . 27
11.9.2 Procedure . 27
11.9.3 Requirements . 28
11.10 Wire/Ribbon bond strength . 28
11.10.1 Purpose . 28
11.10.2 Procedure . 28
11.10.3 Requirements . 30
11.11 Die adhesion . 31
11.11.1 Purpose . 31
11.11.2 Procedure . 31
11.11.3 Requirements . 31
11.12 Connector shear strength . 32
11.12.1 Purpose . 32
11.12.2 Procedure . 32
11.12.3 Pass/fail criteria . 33
11.13 Bypass diode shear strength . 33
11.13.1 Purpose . 33
11.13.2 Procedure . 33
11.13.3 Requirements . 33


Figure 1 – Schematics and photos of Cells on Carrier and bare cell test assembly . 8
Figure 2 – Representative samples of CPV systems, where cells and CoCs are
deployed . 9
Figure 3 – Flow chart of qualification tests for bare solar cells . 18
Figure 4 – Flow chart of qualification tests for CoCs . 19
Figure 5 – Thermal Cycle Diagram for the CoC test and TCO-1 . 24
Figure 6 – Force diagram in the bond strength test (taken from IEC 60749-22:2002,
Annex A, Method B) . 29
Figure 7 – Minimum bond pull limits (normal to die) (taken from IEC 60749-22:2002,
Annex A, Method B) . 30
Figure 8 – Schematic of the test set up for the die adhesion test. 31
Figure 9 – Die shear strength criteria (minimum force versus die attach area) (taken
from MIL.ST-883-K) . 32
Figure 10 – Schematics of the position of the pushing tool (taken from
IEC 62137-1-2:2007) . 33

Table 1 – Qualification tests description for bare solar cells . 14
Table 2 – Qualification tests description for CoCs . 16
Table 3 – Thermal Cycle Options (TCO) of test 11.5 for CoCs . 23
Table 4 – Minimum pulling forces, PW (taken from IEC60749-22:2002, Method B) . 29

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SIST EN IEC 62787:2021
– 4 – IEC 62787:2021 © IEC 2021
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________

CONCENTRATOR PHOTOVOLTAIC (CPV) SOLAR CELLS
AND CELL ON CARRIER (CoC) ASSEMBLIES –
QUALIFICATION

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
rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 62787 has been prepared by subcommittee 82: Solar photovoltaic
energy systems.
The text of this International Standard is based on the following documents:
FDIS Report on voting
82/1818/FDIS 82/1834/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.

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SIST EN IEC 62787:2021
IEC 62787:2021 © IEC 2021 – 5 –
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.

IMPORTANT – The "colour inside" logo on the cover page of this document indicates
that it contains colours which are considered to be useful for the correct understanding
of its contents. Users should therefore print this document using a colour printer.

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SIST EN IEC 62787:2021
– 6 – IEC 62787:2021 © IEC 2021
CONCENTRATOR PHOTOVOLTAIC (CPV) SOLAR CELLS
AND CELL ON CARRIER (CoC) ASSEMBLIES –
QUALIFICATION



1 Scope
This document specifies the minimum requirements for the qualification of concentrator
photovoltaic (CPV) cells and Cell on Carrier (CoC) assemblies for incorporation into CPV
receivers, modules and systems.
The object of this qualification standard is to determine the optoelectronic, mechanical, thermal,
and processing characteristics of CPV cells and CoCs to show that they are capable of
withstanding assembly processes and CPV application environments. The qualification tests of
this document are designed to demonstrate that cells or CoCs are suitable for typical assembly
processes, and when properly assembled, are capable of passing IEC 62108.
This document defines qualification testing for two levels of concentrator photovoltaic device
assembly:
a) cell, or bare cell; and
b) cell on carrier (CoC).
NOTE Note that a variety of alternate names are used within the industry, such as solar cell assembly, receiver,
etc.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies.
For undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 60721-2-1:2013, Classification of environmental conditions – Part 2-1: Environmental
conditions appearing in nature – Temperature and humidity
IEC 60749-3:2017, Semiconductor devices – Mechanical and climatic test methods – Part 3:
External visual examination
IEC 60749-6:2017, Semiconductor devices – Mechanical and climatic test methods – Part 6:
Storage at high temperature
IEC 60749-14:2003, Semiconductor devices – Mechanical and climatic test methods – Part 14:
Robustness of terminations (lead integrity)
IEC 60749-21:2011, Semiconductor devices – Mechanical and climatic test methods – Part 21:
Solderability
IEC 60749-22:2002, Semiconductor devices – Mechanical and climatic test methods – Part 22:
Bond strength
IEC 60904-1-1:2017, Photovoltaic devices – Part 1-1: Measurement of current-voltage
characteristics of multi-junction photovoltaic (PV) devices

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SIST EN IEC 62787:2021
IEC 62787:2021 © IEC 2021 – 7 –
IEC 61000-4-2:2008, Electromagnetic compatibility (EMC) – Part 4-2: Testing and
measurement techniques – Electrostatic discharge immunity test
IEC 61193-2:2007, Quality assessment systems – Part 2 selection and use of sampling plans
for inspection of electronic components and packages
IEC TS 61836:2016, Solar photovoltaic energy systems – Terms, definitions and symbols
IEC 62108:2016, Concentrator photovoltaic (CPV) modules and assemblies – Design
qualification and type approval
IEC 62137-1-2:2007, Surface mounting technology – Environmental and endurance test
methods for surface mount solder joint – Part 1-2: Shear strength test
IEC 62670-1:2013, Photovoltaic concentrators (CPV) – Performance testing – Part 1: Standard
conditions
IEC TS 62789:2014, Photovoltaic concentrator cell documentation
IEC 63202-2, Photovoltaic cells – Part 2: Electroluminescence image for crystalline silicon
solar cells
ECSS-E-ST-20-08C Rev 1, 18 July 2012, Space engineering – Photovoltaic assemblies and
components – Part 7.5.8: Coating adherence (CA)
MIL.ST-883-K, Test Method Standard – Microcircuits Method 2019.9 Die shear strength
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC TS 61836 and
IEC 62108 apply, as well as the following.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1
bare cell
refers to a semiconductor die level. The physical form during a commercial transaction may be
a separated solar cell, a diced wafer on tape, or even a processed wafer. The one common
denominator is that the qualified configuration is completely unprotected and not ready for
interconnection with the rest of a CPV module
Note 1 to entry: For this qualified configuration, the customer is responsible for all integration and assembly.
Note 2 to entry: For some qualification tests, bare cells are mounted on a substrate, heatsink, or other type of
carrier (see Figure 1c). This provides mechanical stability, robust electrical contacts, and appropriate thermal
management, but it is not considered in the bare solar cell qualification.
3.2
Cell on Carrier
CoC
cell bonded and interconnected with a cell carrier, at a minimum (see Figure 1b). This is a
relatively small, assembled unit in a relatively complete and rugged package

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– 8 – IEC 62787:2021 © IEC 2021
Note 1 to entry: A cell on carrier can optionally include a bypass diode, encapsulation of the cell and/or
interconnects and a connector to simplify series or parallel connection. Alternatively, a CoC can also include multiple
cells. A CoC does not include any optical element.
Note 2 to entry: Figure 1 shows an expanded schematic of common components in a CoC, along with two photos.
Note that these photos illustrate relatively simple packages containing one primary photovoltaic device.

a) CoC exploded schematic

b) Cell on Carrier (CoC) with connectors and 2x c) Bare cell test assembly is intended to provide a
packaged diodes. Intended for sale in this test vehicle for bare cell qualification. Bypass diodes
configuration. can be included or not. Not a CoC offered for sale.


Figure 1 – Schematics and photos of Cells on Carrier and bare cell test assembly

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SIST EN IEC 62787:2021
IEC 62787:2021 © IEC 2
...

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