IEC TS 60904-1-2:2024
(Main)Photovoltaic devices - Part 1-2: Measurement of current-voltage characteristics of bifacial photovoltaic (PV) devices
Photovoltaic devices - Part 1-2: Measurement of current-voltage characteristics of bifacial photovoltaic (PV) devices
IEC TS 60904-1-2:2024 describes procedures for the measurement of the current-voltage (I-V) characteristics of single junction bifacial photovoltaic devices in natural or simulated sunlight. It is applicable to encapsulated solar cells, sub-assemblies of such cells or entire PV modules. For measurements of I-V characteristics of non-encapsulated solar cells, IEC TS 63202-3 applies.
The requirements for measurement of I-V characteristics of standard (monofacial) PV devices are covered by IEC 60904-1, whereas this document describes the additional requirements for the measurement of I-V characteristics of bifacial PV devices.
This second edition cancels and replaces the first edition published in 2019. This edition includes the following significant technical changes with respect to the previous edition:
a) The scope has been updated and refers to IEC TS 63202-3 for the measurement of non‑encapsulated solar cells.
b) The requirements for the non-uniformity of irradiance have been updated and now refer to classifications introduced in IEC 60904-9.
c) The requirement for non-irradiated background has been revised.
d) Spectral mismatch corrections are no longer mandatory, unless required by another standard. Spectral mismatch would have to be considered in the measurement uncertainty.
e) The requirement regarding the calculation of bifaciality has been modified: Equivalent irradiance shall not be calculated based on the minimum bifaciality value between ISC and Pmax, but on the bifaciality of ISC.
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IEC TS 60904-1-2 ®
Edition 2.0 2024-11
TECHNICAL
SPECIFICATION
Photovoltaic devices –
Part 1-2: Measurement of current-voltage characteristics of bifacial photovoltaic
(PV) devices
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IEC TS 60904-1-2 ®
Edition 2.0 2024-11
TECHNICAL
SPECIFICATION
Photovoltaic devices –
Part 1-2: Measurement of current-voltage characteristics of bifacial photovoltaic
(PV) devices
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 27.160 ISBN 978-2-8322-9832-9
– 2 – IEC TS 60904-1-2:2024 © IEC 2024
CONTENTS
FOREWORD . 4
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 7
4 General considerations . 9
5 Apparatus . 9
5.1 General . 9
5.2 Solar simulator with adjustable irradiance levels for single-side illumination . 9
5.3 Solar simulator with adjustable irradiance levels for double-side illumination . 9
5.4 Natural sunlight . 10
5.5 Non-irradiated background . 10
5.6 Temperature sensors . 12
6 Additional I-V characterisations for bifacial devices . 12
6.1 General . 12
6.2 Determination of bifaciality . 13
6.3 Determination of the rear irradiance power gain . 14
6.3.1 General . 14
6.3.2 Outdoor rear irradiance power gain measurement . 15
6.3.3 Indoor rear irradiance power gain measurement with single-side
illumination . 16
6.3.4 Indoor rear irradiance power gain measurement with double-side
illumination . 18
7 I-V characterisation of bifacial PV devices in practice . 18
7.1 General . 18
7.2 I-V measurement of bifacial PV devices . 18
7.3 I-V measurement of bifacial PV devices using a reference bifacial device . 19
8 Report . 21
Bibliography . 22
Figure 1 – Two reference devices (described in IEC 60904-2) to measure irradiance on
front and rear sides of device under test during outdoor measurements . 10
Figure 2 – Scheme of a bifacial PV module and the required non-irradiated background
and aperture . 11
Figure 3 – Suggested points to measure the irradiance at the rear face of a PV module
with 72 cells . 12
Figure 4 – Front and rear-side characterization of bifaciality . 13
Figure 5 – Examples of P as a function of irradiance level on the rear side G (for
max r
outdoor or double-side illumination) or its one-side equivalent irradiance G for a
e
φ
device of bifaciality = 89 % . 17
I
SC
Figure 6 – Transmittances of the device (T ) and its encapsulant (T ) . 19
DUT ENC
Figure 7 – Example of P derived from the measurement of P at STC
max,BNPI max
conditions, P and the BiFi coefficient of the reference used in Formula (10) . 20
max,STC
Table 1 – Maximum power, P , measured at different rear irradiances, G , (double-
max r
-2
sided with G = 1 000 Wm ) or alternatively equivalent front irradiances, G , and the
f E
rear irradiance driven power gain yield, BiFi, derived from the slope of the linear fit on
P (G ) . 17
max r
Table 2 – Example of P derived from the measurement at STC conditions
max,BNPI
(G = 0 and G = 1 000) and the rear irradiance power gain obtained from the bifacial
r f
reference device, BiFi . 20
ref
– 4 – IEC TS 60904-1-2:2024 © IEC 2024
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
PHOTOVOLTAIC DEVICES –
Part 1-2: Measurement of current-voltage characteristics of
bifacial photovoltaic (PV) devices
FOREWORD
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IEC TS 60904-1-2 has been prepared by IEC technical committee 82: Solar photovoltaic energy
systems. It is a Technical Specification.
This second edition cancels and replaces the first edition published in 2019. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) The scope has been updated and refers to IEC TS 63202-3 for the measurement of
non-encapsulated solar cells.
b) The requirements for the non-uniformity of irradiance have been updated and now refer to
classifications introduced in IEC 60904-9.
c) The requirement for non-irradiated background has been revised.
d) Spectral mismatch corrections are no longer mandatory, unless required by another
standard. Spectral mismatch would have to be considered in the measurement uncertainty.
e) The requirement regarding the calculation of bifaciality has been modified: Equivalent
irradiance shall not be calculated based on the minimum bifaciality value between I and
SC
P , but on the bifaciality of I .
max SC
The text of this Technical Specification is based on the following documents:
Draft Report on voting
82/2278/DTS 82/2309/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/publications.
A list of all parts in the IEC 60904 series, published under the general title Photovoltaic devices,
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
...
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