IEC TS 63109:2022

IEC TS 63109 ®
Edition 1.0 2022-03
TECHNICAL
SPECIFICATION
Photovoltaic (PV) modules and cells – Measurement of diode ideality factor by
quantitative analysis of electroluminescence images
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IEC TS 63109 ®
Edition 1.0 2022-03
TECHNICAL
SPECIFICATION
Photovoltaic (PV) modules and cells – Measurement of diode ideality factor by

quantitative analysis of electroluminescence images

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 27.160 ISBN 978-2-8322-1090-3

– 2 – IEC 63109:2022 © IEC 2022
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 7
4 Procedures for quantitative analysis of EL intensity . 8
4.1 General . 8
4.2 Samples. 9
4.3 Apparatus . 9
4.4 EL image capturing and camera calibration . 9
4.5 Procedures of analysing data to derive n values (refer to Annex A) . 9
5 Measurement report . 9
Annex A (normative) EL intensity dependence on the injection current . 11
A.1 General . 11
A.2 Derivation of diode ideality factor . 11
Annex B (informative) Examples of measurements of diode ideality factor n . 13
B.1 General . 13
B.2 Examples of n value of cells . 13
B.2.1 Example 1 – Module without defect. 13
B.2.2 Module with defect . 15
Annex C (informative) Diode ideality factor n as an indicator of the output
performance of PV modules – Measurement using proposed single diode model – . 19
C.1 General . 19
C.2 Practical single diode model . 20
C.3 Concise derivation method of n using photo response parameters . 26
Bibliography . 28

Figure 1 – Scheme for labeling position of cells in a module viewed from the light-
facing side according to coordinates (i,j) . 10
Figure A.1 – Electroluminescence intensity dependence on injection current . 12
Figure B.1 – EL image (module without defect) . 13
Figure B.2 – EL intensity dependence on injection current (module without defect) . 14
Figure B.3 – EL image (aged module) . 15
Figure B.4 – EL intensity dependence on injection current (aged module) . 15
Figure B.5 – Diode ideality factor n of 3,F . 16
Figure B.6 – EL image (defective module) . 17
Figure B.7 – EL intensity dependence on injection current (defective module) . 17
Figure B.8 – Diode ideality factor n of 4,E . 18
Figure C.1 – Equivalent circuit model in dark considering series resistance R and
s
shunt resistance R . 20
sh
Figure C.2 – Equivalent circuit model in dark for the practical single diode model . 20
Figure C.3 – Schematic I-V characteristic in dark using linear coordinates . 21
Figure C.4 – Schematic I-V characteristic in dark using semi-logarithmic scales . 21

IEC 63109:2022 © IEC 2022 – 3 –
Figure C.5 – Equivalent circuit model under photo irradiation considering series
resistance R . 23
s
Figure C.6 – Equivalent circuit model under photo irradiation for practical single diode

model . 23
Figure C.7 – Photo response showing I – V characteristic flowing through the load . 24
ph ph
Figure C.8 – Diode current as a function of the diode voltage . 25
Figure C.9 – Semi-logarithmic plot of diode current versus diode voltage . 25
Figure C.10 – Schematic consideration of photo-response change with increasing the
diode ideality factor n . 26

Table B.1 – Performance of module without defect (module A) (at STC) . 14
Table B.2 – Performance of aged module (module B) (at STC) . 16
Table B.3 – Performance of PID module (at STC) . 18

– 4 – IEC 63109:2022 © IEC 2022
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
PHOTOVOLTAIC (PV) MODULES AND CELLS –
MEASUREMENT OF DIODE IDEALITY FACTOR BY QUANTITATIVE
ANALYSIS OF ELECTROLUMINESCENCE IMAGES

FOREWORD
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IEC TS 63109 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
82/1955/DTS 82/1992/RVDTS
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this Technical Specification is English.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/standardsdev/publications.

IEC 63109:2022 © IEC 2022 – 5 –
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under 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.
– 6 – IEC 63109:2022 © IEC 2022
INTRODUCTION
EL (Electroluminescence) diagnosis technique has been widely used for the evaluation of
photovoltaic cells and modules photographically. EL images can identify various kinds of
deficiencies, such as cracks and pin-holes in substrates, breakdown and detachment of
electrodes, etc. In addition to these qualitative inspections, the quantitative analysis of EL
intensity can reveal the electronic performance of photovoltaic cells [1] to [7] . The EL inten
...