IEC TS 63202-2:2021

IEC TS 63202-2 ®
Edition 1.0 2021-12
TECHNICAL
SPECIFICATION
colour
inside
Photovoltaic cells –
Part 2: Electroluminescence imaging of crystalline silicon solar cells
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IEC TS 63202-2 ®
Edition 1.0 2021-12
TECHNICAL
SPECIFICATION
colour
inside
Photovoltaic cells –
Part 2: Electroluminescence imaging of crystalline silicon solar cells

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 27.160 ISBN 978-2-8322-1061-1

– 2 – IEC TS 63202-2:2021 © IEC 2021
CONTENTS
FOREWORD . 3
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
4 Imaging . 7
4.1 Apparatus . 7
4.1.1 General . 7
4.1.2 Electroluminescence imaging camera . 7
4.1.3 Dark room imaging studio or environment . 8
4.1.4 Power supply . 9
4.1.5 Image processing and displaying software . 9
4.2 Procedure . 10
4.2.1 Camera settings and positioning . 10
4.2.2 Camera setting . 10
4.2.3 Imaging . 11
4.2.4 Image correction . 12
5 Evaluation of EL images . 12
5.1 Principles of electroluminescence . 12
5.2 Image interpretation . 12
5.2.1 Series resistance . 12
5.2.2 Minority carrier lifetime and diffusion length . 13
5.2.3 Shunt resistance . 13
5.2.4 Assignment of root cause . 13
5.2.5 Qualitative image interpretation . 13
6 Reporting. 18
Bibliography . 19

Figure 1 – Typical setup of an electroluminescence imaging system . 7
Figure 2 – Image of multi-crystalline silicon solar cell with SNR value of 45 . 8
Figure 3 – EL images of PV solar cell with broken fingers . 14
Figure 4 – EL images of PV cell with different grades of concentric circles in mono-
crystalline silicon . 15
Figure 5 – EL images of PV cell with local shunting . 16
Figure 6 – EL images of PV mono-crystalline silicon solar cells . 16
Figure 7 – EL images of PV multi-crystalline silicon solar cells. 17
Figure 8 – EL images of PV cell . 17

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
PHOTOVOLTAIC CELLS –
Part 2: Electroluminescence imaging
of crystalline silicon solar cells

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
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IEC TS 63202-2 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
82/1912/DTS 82/1951/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.

– 4 – IEC TS 63202-2:2021 © IEC 2021
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.
A list of all parts in the IEC 63202 series, published under the general title Photovoltaic cells,
can be found on the IEC website.
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.
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contents. Users should therefore print this document using a colour printer.

PHOTOVOLTAIC CELLS –
Part 2: Electroluminescence imaging
of crystalline silicon solar cells

1 Scope
This part of IEC 63202 specifies methods to detect and examine defects on bare crystalline
silicon (c-Si) solar cells by means of electroluminescence (EL) imaging with the cell being
placed in forward bias. It firstly provides guidelines for methods to capture electroluminescence
images of non-encapsulated c-Si solar cells. In addition, it provides a list of defects which can
be detected by EL imaging and provides information on the different possible methods to detect
and differentiate such defects. When EL imaging alone cannot provide conclusive information
for the presence of a type of defect, suggestions are also made to utilize a combination of other
methods.
Finally, this document provides some information on potential effects when using cells with
specific EL features in module assembly. Although this document mainly addresses bare c-Si
solar cells, it is generally applicable to all wafer solar cell technologies.
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 TS 60904-13:2018, Photovoltaic devices – Part 13: Electroluminescence of photovoltaic
modules
IEC TS 61836:2016, Solar photovoltaic energy systems – Terms, definitions and symbols
IEC TS 62446-3, Photovoltaic (PV) systems – Requirements for testing, documentation and
maintenance – Part 3: Photovoltaic modules and plants – Outdoor infrared thermography
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC TS 61836, together
with the following, apply.
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1
electroluminescence
EL
light emission by radiative recombination of excited charge carriers in a semiconductor device
resulting from electrical voltage applied to the semiconductor in forward
...