oSIST prEN IEC 62973-5:2025

SLOVENSKI STANDARD
01-december-2025
Železniške naprave - Vozna sredstva - Baterije za pomožne močnostne napajalne
sisteme - 5. del: Litij-ionske baterije
Railway applications - Rolling stock - Batteries for auxiliary power supply systems - Part
5: Lithium-ion batteries
Bahnanwendungen - Fahrzeuge - Batterien für Bordnetzversorgungssysteme – Teil 5:
Lithium-Ionen Batterien
Applications ferroviaires - Matériel roulant -Batteries pour systèmes d'alimentation
auxiliaire - Partie 5: Batteries lithium-ion
Ta slovenski standard je istoveten z: prEN IEC 62973-5:2025
ICS:
29.220.20 Kislinski sekundarni členi in Acid secondary cells and
baterije batteries
45.060.01 Železniška vozila na splošno Railway rolling stock in
general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD DRAFT
prEN IEC 62973-5
NORME EUROPÉENNE
EUROPÄISCHE NORM
October 2025
ICS 29.220.20 -
English Version
Railway applications - Rolling stock - Batteries for auxiliary
power supply systems - Part 5: Lithium-ion batteries
(IEC 62973-5:2023)
Applications ferroviaires - Matériel roulant -Batteries pour Bahnanwendungen - Fahrzeuge - Batterien für
systèmes d'alimentation auxiliaire - Partie 5: Batteries Bordnetzversorgungssysteme - Teil 5: Lithium-Ionen
lithium-ion Batterien
(IEC 62973-5:2023) (IEC 62973-5:2023)
This draft European Standard is submitted to CENELEC members for enquiry.
Deadline for CENELEC: 2026-01-02.

The text of this draft consists of the text of IEC 62973-5:2023.

If this draft becomes a European Standard, 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.

This draft European Standard was established by CENELEC 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,
Türkiye and the United Kingdom.

Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are aware and to
provide supporting documentation.

Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without notice and
shall not be referred to as a European Standard.

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
© 2025 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Project: 81987 Ref. No. prEN IEC 62973-5:2025 E

European foreword
This document (prEN IEC 62973-5:2025) consists of the text of IEC 62973-5:2023 prepared by IEC/TC 9
"Electrical equipment and systems for railways".
This document is currently submitted to the Enquiry.
The following dates are proposed:
• latest date by which the existence of this document has (doa) dav+ 6 months
to be announced at national level
• latest date by which this document has to be (dop) dav+ 12 months
implemented at national level by publication of an
identical national standard or by endorsement
• latest date by which the national standards conflicting (dow) dav+ 36 months
with this document have to be withdrawn (to be confirmed or
modified when voting)
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.cencenelec.eu.
Publication Year Title EN/HD Year
IEC 60077-1 2017 Railway applications - Electric equipment EN 60077-1 2017
for rolling stock - Part 1: General service
conditions and general rules
IEC 62498-1 2010 Railway applications - Environmental - -
conditions for equipment - Part 1:
Equipment on board rolling stock
IEC 60529 1989 Degrees of protection provided by EN 60529 1991
enclosures (IP Code)
- - + AC 1993
+ A1 1999 + A1 2000
+ A2 2013 + A2 2013
IEC 62619 2022 Secondary cells and batteries containing EN IEC 62619 2022
alkaline or other non-acid electrolytes -
Safety requirements for secondary lithium
cells and batteries, for use in industrial
applications
IEC 62620 2014 Secondary cells and batteries containing EN 62620 2015
alkaline or other non-acid electrolytes -
Secondary lithium cells and batteries for
use in industrial applications
IEC 62928 2017 Railway applications - Rolling stock - EN IEC 62928 2018
Onboard lithium-ion traction batteries
IEC 62973-1 2018 Railway applications - Rolling stock - EN IEC 62973-1 —
Batteries for auxiliary power supply
systems - Part 1: General Requirements
ISO 7010 2019 Graphical symbols - Safety colours and EN ISO 7010 -
safety signs - Registered safety signs

Under preparation. Stage at the time of publication: prEN IEC 62973-1:2025.
IEC 62973-5 ®
Edition 1.0 2023-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Railway applications – Rolling stock – Batteries for auxiliary power supply
systems –
Part 5: Lithium-ion batteries
Applications ferroviaires – Matériel roulant – Batteries pour systèmes
d'alimentation auxiliaire –
Partie 5: Batteries lithium-ion
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.220.20; 45.060.01 ISBN 978-2-8322-7369-2
– 2 – IEC 62973-5:2023 © IEC 2023
CONTENTS
FOREWORD . 5
1 Scope . 7
2 Normative references . 7
3 Terms, definitions and abbreviated terms . 8
3.1 Terms and definitions . 8
3.2 Abbreviated terms . 10
4 General requirements . 11
4.1 Architecture of an auxiliary battery system in the train . 11
4.2 Definitions of components of a battery system . 12
4.3 Definitions of battery type . 13
4.3.1 General . 13
4.3.2 Designations for cells and battery system . 14
4.4 Environmental conditions . 14
4.4.1 Battery system . 14
4.4.2 Battery pack/module . 14
4.5 System requirements . 14
4.5.1 System voltage . 14
4.5.2 Charging requirements . 15
4.5.3 Discharging requirements . 16
4.5.4 Charge retention (self-discharge) . 17
4.5.5 Requirements for battery capacity sizing. 17
4.6 Safety and protection requirements . 18
4.6.1 General . 18
4.6.2 Deep discharge of batteries . 18
4.6.3 Temperature related parameters for charge . 18
4.6.4 Exceptional use case of the battery system . 18
4.7 Fire protection . 18
4.8 Maintenance . 19
4.9 Charging characteristics . 19
4.10 Battery management system (BMS) . 19
5 Mechanical design of battery system . 19
5.1 General . 19
5.2 Interface mechanism . 20
5.2.1 General . 20
5.2.2 Fixed type . 20
5.2.3 Roller type . 20
5.2.4 Slide type . 20
5.3 Location of battery system on the vehicle . 20
5.4 Accessibility to the battery . 20
5.5 Ventilation and air flow management of the battery . 20
6 Electrical interface . 21
6.1 General . 21
6.1.1 General overview . 21
6.1.2 Electrical interface for shore supply (optional) . 22
6.2 External electrical connections interface . 23
6.3 Control and communication . 23

IEC 62973-5:2023 © IEC 2023 – 3 –
6.4 Maintenance . 23
7 Markings. 23
7.1 Safety signs . 23
7.1.1 Outside the box . 23
7.1.2 Tray, crate or other places inside the box . 23
7.1.3 Cells or battery pack/modules . 24
7.2 Nameplate . 24
7.2.1 Battery box . 24
7.2.2 Nameplates on tray or other nameplates inside the box . 24
7.2.3 Cells or battery pack/modules . 24
8 Storage and transportation conditions . 24
8.1 Transportation . 24
8.2 Storage of batteries . 24
9 Testing . 25
9.1 General . 25
9.2 Parameter measurement tolerances . 27
9.3 Type and routine tests . 27
9.3.1 General . 27
9.3.2 Electrical characteristics tests . 27
9.3.3 Dielectric test . 28
9.3.4 Self-discharge test . 28
9.3.5 Operational balancing test . 29
9.3.6 Mechanical tests . 30
9.3.7 Load profile test . 31
9.3.8 Endurance in cycles. 31
9.3.9 Battery management system (BMS) tests . 31
9.3.10 Safety tests . 31
Annex A (informative) Declaration of the representative cell/module for tests. 33
A.1 Electrical performance test cell . 33
A.2 Shock and vibration test cell . 33
A.3 Electrical performance test module . 33
A.4 Shock and vibration test module . 33
Bibliography . 34

Figure 1 – Typical integration of an auxiliary battery system in the energy distribution
architecture . 12
Figure 2 – Typical hierarchy of the auxiliary battery system . 13
Figure 3 – Example of discharge curves at various constant discharge currents based
on percentage of capacity . 15
Figure 4 – Examples of charge curves . 15
Figure 5 – Example schematic of an auxiliary battery system . 21
Figure 6 – Example of an auxiliary battery system circuit layout with shore supply
connections . 22
Figure 7 – Illustration of self-discharge test. 29

– 4 – IEC 62973-5:2023 © IEC 2023
Table 1 – Requirements of the charging characteristics . 16
Table 2 – Parameters and responsibility for battery capacity sizing . 17
Table 3 – Type test and routine test . 25

IEC 62973-5:2023 © IEC 2023 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
RAILWAY APPLICATIONS – ROLLING STOCK –
BATTERIES FOR AUXILIARY POWER SUPPLY SYSTEMS –

Part 5: Lithium-ion batteries
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.
IEC 62973-5 has been prepared by IEC technical committee 9: Electrical equipment and
systems for railways. It is an International Standard.
The text of this International Standard is based on the following documents:
Draft Report on voting
9/2974/FDIS 9/2995/RVD
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 International Standard is English.

– 6 – IEC 62973-5:2023 © IEC 2023
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 62973 series, published under the general title Railway applications
– Rolling stock – Batteries for auxiliary power supply systems, 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.
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.

IEC 62973-5:2023 © IEC 2023 – 7 –
RAILWAY APPLICATIONS – ROLLING STOCK –
BATTERIES FOR AUXILIARY POWER SUPPLY SYSTEMS –

Part 5: Lithium-ion batteries
1 Scope
This part of IEC 62973 applies to lithium-ion batteries for auxiliary power supply systems used
on rolling stock. This document specifies the requirements of the characteristics and tests for
the lithium-ion cells, and supplements IEC 62973-1 which is applied to any rolling stock types
(e.g. light rail vehicles, tramways, streetcars, metros, commuter trains, regional trains, high
speed trains, locomotives, etc.).
Unless otherwise specified in this document, the requirements of IEC 62973-1 apply.
This document specifies the requirements of the interface between battery system including
BMS and the converter.
This document is used in conjunction with generic IEC 62619 (safety requirements) and
IEC 62620 (performance requirements) of lithium-ion cells and batteries used in industrial
applications. This document specifies the requirements for railway rolling stock applications.
Such batteries for auxiliary power supply systems are also sometimes used for:
– occasional traction power for shunting in depot, or for rescue or emergency mode such as
stop on third rail gaps;
– peak power shaving and engine starting.
If the nominal battery voltage exceeds the voltage specified in Table 1 of IEC 62973-1:2018,
then IEC 62928 applies to the battery.
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 60077-1:2017, Railway applications – Electric equipment for rolling stock – Part 1: General
service conditions and general rules
IEC 62498-1:2010, Railway applications – Environmental conditions for equipment – Part 1:
Equipment on board rolling stock
IEC 60529:1989, Degrees of protection provided by enclosures (IP Code)
IEC 60529:1989/AMD1:1991
IEC 60529:1989/AMD2:2013
IEC 62619:2022, Secondary cells and batteries containing alkaline or other non-acid
electrolytes – Safety requirements secondary lithium cells and batteries for use in industrial
applications
– 8 – IEC 62973-5:2023 © IEC 2023
IEC 62620:2014, Secondary cells and batteries containing alkaline or other non-acid
electrolytes – Large format secondary lithium cells and batteries, for use in industrial
applications
IEC 62928:2017, Railway applications – Rolling stock – Onboard lithium-ion traction batteries
IEC 62973-1:2018, Railway applications Rolling stock – Batteries for auxiliary power supply
systems – Part 1: General requirements
ISO 7010, Graphical symbols – Safety colours and safety signs – Registered safety signs
3 Terms, definitions and abbreviated terms
3.1 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 62973-1:2018, and
the following apply.
ISO and IEC maintain terminology databases for use in standardization at the following
addresses:
• IEC Electropedia: available at https://www.electropedia.org/
• ISO Online browsing platform: available at https://www.iso.org/obp
NOTE 1 In case there is the same term and definition in IEC 62973-1:2018, then the definition given in this
document applies.
NOTE 2 All typical battery related descriptions are defined in IEC 60050-482.
3.1.1
cell
secondary lithium cell
secondary cell where electrical energy is derived from the insertion/extraction reactions of
lithium-ions or oxidation/reduction reaction of lithium between the negative electrode and the
positive electrode
Note 1 to entry: The cell typically has an electrolyte that consists of a lithium salt and organic solvent compound in
liquid, gel or solid form and has a metal or a laminate film casing. It is not ready for use in an application because it
is not yet fitted with its final housing, terminal arrangement and electronic control device.
[SOURCE: IEC 62620:2014, 3.6]
3.1.2
cell block
group of cells connected together in parallel configuration with or without protective devices
(e.g. fuse or PTC device) and monitoring circuitry
Note 1 to entry: It is not ready for use in an application because it is not yet fitted with its final housing, terminal
arrangement and electronic control device.
[SOURCE: IEC 62620:2014, 3.7, modified – The word "device" has been added after "PTC" in
the definition.]
IEC 62973-5:2023 © IEC 2023 – 9 –
3.1.3
battery pack
module
group of cells connected together either in series and/or parallel configuration with or without
protective devices (e.g. fuse or PTC device) and monitoring circuitry
Note 1 to entry: It incorporates a protective housing and be provided with terminals or other interconnection
arrangement.
Note 2 to entry: It includes at least monitoring circuitry, which provides information (e.g. cell voltage, temperature)
to a battery system.
Note 3 to entry: It may include a protective device and control circuitry.
[SOURCE: IEC 62973-1:2018, 3.1.9, modified – The term "battery module" has been replaced
with "battery pack" and "module", in the definition, "temperature sensor" has been replaced with
"PTC" and notes to entry added.]
3.1.4
rated capacity
capacity value determined under specified conditions and declared by the
manufacturer
Note 1 to entry: The rated capacity is the quantity of electricity Cn Ah (ampere-hours) declared by the manufacturer
which a single cell or battery can deliver during a n h period when charging, storing and discharging under the
conditions specified in IEC 62620:2014, 6.3.1. n is 5 for an E, M and H discharge rate type cell or battery. n is 8, 10,
20 or 240 for an S discharge rate type battery.
[SOURCE: IEC 62620:2014, 3.5, modified – domain added, "of a cell or battery"
deleted from the definition, and in Note 1 to entry, IEC 62620:2014 has been added.]
3.1.5
battery system
system which incorporates one or more cells, modules or battery
packs including battery management system and thermal management system as well as
disconnecting and/or isolating devices, e.g. contactors, disconnectors, fuses, etc.
Note 1 to entry: Refer to Figure 2, Figure 3 and Figure A.1 to Figure A.4 in IEC 62928:2017.
[SOURCE: IEC 62928:2017, 3.1.11, modified – domain added.]
3.1.6
battery management system
BMS
system associated with a battery pack which monitors and/or manages its state, disconnects or
isolates the battery pack, calculates secondary data, communicates data outside of the battery
system and/or controls its environment to influence the battery's safety, performance and/or
service life
Note 1 to entry: The function of the BMS can be assigned to the battery pack or to equipment that uses the battery
pack.
Note 2 to entry: Its function includes thermal control.
[SOURCE: IEC 62620:2014, 3.11, modified – "electronic" has been deleted, "disconnects or
isolates the battery pack," has been added, "reports that data" has been replaced with
"communicates data outside of the battery system" and "and has the functions to cut …" has
been deleted. Note 2 to entry has been replaced.]

– 10 – IEC 62973-5:2023 © IEC 2023
3.1.7
battery thermal management system
BTMS
system associated with a battery pack which monitors and/or manages its thermal behaviour in
order to maintain the temperature of the battery pack in the intended range for load profile
agreed between the integrator and the battery system manufacturers
Note 1 to entry: BTMS is optional to control environmental conditions inside the battery system, e.g. air conditioning
(temperature, humidity, etc.).
[SOURCE: IEC 62928:2017, 3.1.30, modified – Note to entry added.]
3.1.8
emergency mode
operating situation of rolling stock when primary power is not available
3.1.9
exceptional use case
situation exceeding the worst case of an agreed load profile
3.1.10
end user
organization which operates the lithium-ion battery system
Note 1 to entry: The end user is normally an organization which operates the vehicle equipped with the battery
system, unless the responsibility is delegated to a main contractor or consultant.
[SOURCE: IEC 62973-1:2018, 3.1.11, modified – "lithium-ion" inserted.]
3.1.11
system integrator
organization which has the technical responsibility of the complete lithium-ion battery system
including BMS and charging system
Note 1 to entry: The system integrator can be the end user or the train manufacturer, or neither of them.
[SOURCE: IEC 62973-1:2018, 3.1.12, modified, – "lithium-ion" and "including BMS" inserted.]
3.1.12
manufacturer
organization which has the technical responsibility for its scope of supply
Note 1 to entry: The manufacturer can be the train builder or the system integrator of a battery system, a cell
manufacturer, etc. If necessary to explicitly distinguish, "train manufacturer", "battery system manufacturer" or "cell
manufacturer" is specified.
[SOURCE: IEC 62973-1:2018, 3.1.13, modified, – In the Note to entry, "is expressed" has been
replaced with "is specified".]
3.2 Abbreviated terms
AC Alternating Current
APU Auxiliary Power Unit
DC Direct Current
DOD Depth of Discharge
FEA Finite Element Analysis
LRU Line Replaceable Unit
LVPS Low Voltage Power System
IEC 62973-5:2023 © IEC 2023 – 11 –
PTC Positive Temperature Coefficient
SOC State of Charge
4 General requirements
4.1 Architecture of an auxiliary battery system in the train
Typical architecture of an auxiliary battery system including its integration into the train system
is shown in Figure 1.
– 12 – IEC 62973-5:2023 © IEC 2023

Key
AL Auxiliary load
APS Auxiliary power supply
APU Auxiliary power unit
AUX Auxiliary system
BCH Brake chopper
BR Brake resistor
CH Chopper converter
ESS Energy storage system
ESU Energy storage unit
INV Inverter
LVPS Low voltage power system
PPS Primary power source
TE Traction equipment
Figure 1 – Typical integration of an auxiliary battery system
in the energy distribution architecture
4.2 Definitions of components of a battery system
Figure 2 shows typical hierarchy of the auxiliary battery system. Images are examples of the
level of integration of cells, battery packs/modules, trays and battery boxes.

IEC 62973-5:2023 © IEC 2023 – 13 –

Figure 2 – Typical hierarchy of the auxiliary battery system
Some batteries can include some of the above components, e.g. battery packs/modules may
be installed in a battery box without a tray.
4.3 Definitions of battery type
4.3.1 General
A battery system consists of a number of cells, cell blocks or battery pack/modules that are
assembled in trays and then assembled in a battery box. Each cell contains electrolyte and
stacked, wound or folded positive electrode(s), negative electrode(s) and separators. The
electrodes are connected to positive and negative terminals that are accessible on the outside
of the cell container.
Secondary lithium cells may contain multiple types of lithium compounds which result in
different properties, performances and operational parameters. Different types of cells shall not
be mixed together in same battery without formal approval from the battery system manufacturer
and cell manufacturer.
– 14 – IEC 62973-5:2023 © IEC 2023
4.3.2 Designations for cells and battery system
The cells shall be designated as follows:
• A1A2A3/N2/N3/N4/ A4/TLTH/ NC
Details of this form are found in IEC 62620:2014, 5.2.
The battery pack/module and the battery system shall be designated as follows:
• A1A2A3/N2/N3/N4/[S1]A4/TLTH/NC
Details of this form are found in IEC 62620:2014, 5.3.
4.4 Environmental conditions
4.4.1 Battery system
The battery has to ensure an appropriate function for the given requirements including
exceptional use case with respect to safety, lifetime, chargeability and discharge performance.
The battery shall not be operated outside specified environmental limit conditions of the specific
cell and battery system.
The cells or battery packs/modules in the battery box shall be protected during use against
environmental conditions as described in IEC 62498-1. During transportation, UN 38.3 applies.
The deviations may be agreed between cell manufacturer, battery system manufacturer and
system integrator and/or end user.
4.4.2 Battery pack/module
Battery pack/modules when integrated in the battery system including BTMS can operate in a
range of ambient temperature −25 °C to +40 °C unless otherwise specified. The cell shall
remain in its specified operating region as described in IEC 62619.
The deviations may be agreed between cell manufacturer, battery system manufacturer and
system integrator and/or end user.
4.5 System requirements
4.5.1 System voltage
For the system voltage, refer to IEC 62973-1:2018, 4.4.1.
The battery nominal voltages and the discharge voltages are different. As an example, Figure 3
shows examples of discharges of a cell at different constant discharging currents. These
currents are expressed as multiples of I A, where I A = C Ah/1 h. Those curves are dependent
t t 5
on the technology of specific cells and/or their design, and shall be available from the cell
manufacturers.
IEC 62973-5:2023 © IEC 2023 – 15 –

Figure 3 – Example of discharge curves at various constant discharge
currents based on percentage of capacity
Figure 4 a) and b) show a typical charge of a cell at constant current charging to the voltage
predefined by the cell manufacturer for the initial phase followed by constant voltage charging
for the last phase.
Charging curves are also dependent on the technology of specific cells and/or their design, and
shall be available from the cell manufacturers.
≈
a) Example of charge current curve b) Example of charge voltage curve

NOTE The positive sign of current shows the charging condition. This is different from the definition in IEC 62928
for traction purpose.
Figure 4 – Examples of charge curves
4.5.2 Charging requirements
The requirements of the charging characteristics are specified according to Table 1.

– 16 – IEC 62973-5:2023 © IEC 2023
Table 1 – Requirements of the charging characteristics
Activity Requirements
Connected, when operational, to the power converter for the battery
Normal condition and auxiliary equipment and brought to the specified SOC level
agreed between battery manufacturer and system integrator.
Constant current and constant voltage (CC-CV) method or charging
method specified by the battery system manufacturer.
Charging method
Controls shall be present to prevent overcharge (of each cell),
overcurrent and over temperature of the battery.
Tolerance (allowable level of error) of the charge current level vs
Steady state control tolerance of the
specified current in steady state conditions during the CC phase.
battery charge current output at the
charging system for CC phase
± 5 % or lower
Tolerance (allowable level of error) of the charge voltage level vs
Steady state control tolerance of the
specified voltage in steady state conditions during the CV phase.
battery charge voltage output at the
charging system for CV phase
± 1 % or lower
≤ 5 % (according to IEC 60077-1:2017, 8.2.1.8 but with battery
Charging voltage ripple
disconnected)
Charging current ripple Refer to IEC 62928:2017, 10.2
Temperature compensation Refer to 4.6.3
Signal from sensor on cell or module is sent to the BMS and
Monitoring temperature  optionally to the BTMS. The power converter for the battery and
auxiliary equipment shall operate according to the BMS information.
To be present.
Over-voltage charging protections
Refer to 4.6.1 and 4.9
For charging interface, refer to 6.1.
4.5.3 Discharging requirements
4.5.3.1 General
Refer to IEC 62973-1:2018, 4.4.3.1.
If there are some specific requirements in lithium ion technology that are different from what
IEC 62973-1 specifies, this document applies.
NOTE When applying IEC 62973-1:2018 in this document, "battery" equals "battery system". See 3.1.5.
4.5.3.2 Load profile
Refer to IEC 62973-1:2018, 4.4.3.2.
Load profiles of the emergency cases shall be defined.
4.5.3.3 Extended discharge time
Refer to IEC 62973-1:2018, 4.4.3.3.
Further use shall not be allowed when any cell within a branch is discharged to a voltage lower
than that specified by the cell manufacturer.
4.5.3.4 Low or high temperature performance
Refer to IEC 62973-1:2018, 4.4.3.4.

IEC 62973-5:2023 © IEC 2023 – 17 –
4.5.4 Charge retention (self-discharge)
In railway application, long-duration storage and transportation can occur before and/or after
commissioning of rolling stock. The battery system shall be operable for commissioning and
operation.
Charge retention of cells, which is reduced by self-discharge, is specified in IEC 62620:2014,
6.4.
Additional components, e.g. balancing function of the BMS, increase the self-discharge rate of
the battery system. Guidance on the battery system to ensure a safe transport as well as an
appropriate operation after a long duration of transportation and/or storage before installation
on rolling stock and commissioning shall be provided by the battery system manufacturer.
The time period after commissioning and delivery of the built rolling stock to the end user's site
until revenue operation starts should be defined by the end user, and considered in the battery
system design.
The battery system manufacturer shall define additional maintenance equipment, software,
procedures, etc., for long-duration storage.
4.5.5 Requirements for battery capacity sizing
Refer to IEC 62973-1:2018, 4.4.5.
For battery capacity sizing, values according to Table 2 shall be provided by the responsible
party as set out in Table 2.
Table 2 – Parameters and responsibility for battery capacity sizing
Parameters needed for battery Responsibility for providing the Values
sizing parameters
Load profile (W and/or Ω and/or A) The system integrator so as to fulfil Load profile cases in W and/or Ω
the requirement of train and/or A each over a specified
manufacturer duration period
High and low temperature for sizing The train manufacturer or in High and low temperature in °C as
to the load profile (°C) conjunction with the end user specified by train manufacturer and
train operator, etc. in the
environment of the battery system.
Charging voltage for battery The battery or cell manufacturer Number of cells × required
system charging voltage per cell
The level of state of charge (SOC) The battery or cell manufacturer Percentage of rated capacity as set
at 25 °C end of charge conditions out in IEC 62620
in operation (%)
Requested cycle capability The train manufacturer or in Number of the total cycles (full or
conjunction with the end user partial) and their frequency
(number of load profile discharges
followed by recharges)
Useful battery life at an average The battery or cell manufacturer Years of life duration under typical
annual operating temperature of railway conditions
approximately 20 °C under railway
conditions (years)
Ageing factor (%) The battery or cell manufacturer Percentage of rated capacity as set
out in IEC 62620
DC internal resistance at the start
and the end of the useful battery
life.
– 18 – IEC 62973-5:2023 © IEC 2023
4.6 Safety and protection requirements
4.6.1 General
For safet
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