EN ISO 23625:2025

SLOVENSKI STANDARD
01-maj-2025
Mala plovila - Litij-ionske baterije (ISO 23625:2025)
Small craft - Lithium-ion batteries (ISO 23625:2025)
Kleinfahrzeuge - Lithium-Ionen-Batterien (ISO 23625:2025)
Petits navires - Batteries lithium-ion (ISO 23625:2025)
Ta slovenski standard je istoveten z: EN ISO 23625:2025
ICS:
29.220.01 Galvanski členi in baterije na Galvanic cells and batteries
splošno in general
47.080 Čolni Small craft
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 23625
EUROPEAN STANDARD
NORME EUROPÉENNE
March 2025
EUROPÄISCHE NORM
ICS 47.080 Supersedes CEN ISO/TS 23625:2022
English Version
Small craft - Lithium-ion batteries (ISO 23625:2025)
Petits navires - Batteries lithium-ion (ISO 23625:2025) Kleinfahrzeuge - Lithium-Ionen-Batterien (ISO
23625:2025)
This European Standard was approved by CEN on 11 March 2025.

CEN 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 CEN
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 CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2025 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 23625:2025 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
This document (EN ISO 23625:2025) has been prepared by Technical Committee ISO/TC 188 "Small
craft" in collaboration with Technical Committee CEN/TC 464 “Small Craft” the secretariat of which is
held by SIS.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by September 2025, and conflicting national standards
shall be withdrawn at the latest by September 2025.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes CEN ISO/TS 23625:2022.
Any feedback and questions on this document should be directed to the users’ national standards
body/national committee. A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the
United Kingdom.
Endorsement notice
The text of ISO 23625:2025 has been approved by CEN as EN ISO 23625:2025 without any modification.

International
Standard
ISO 23625
First edition
Small craft — Lithium-ion batteries
2025-03
Petits navires — Batteries lithium-ion
Reference number
ISO 23625:2025(en) © ISO 2025
ISO 23625:2025(en)
© ISO 2025
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
ISO 23625:2025(en)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 System design requirements . 4
5 Safe operating limits . 5
6 General lithium-ion battery installations. 5
7 Fire protection and cell venting . 6
8 Battery management system and testing. 7
9 Manufacturer’s safety information and operator’s manual . 8
Annex A (informative) Battery thermal runaway . 10
Annex B (informative) Protection devices .13
Annex C (informative) Protection device examples . 14
Bibliography . 17

iii
ISO 23625:2025(en)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee
has been established has the right to be represented on that committee. International organizations,
governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely
with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
of ISO document should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO’s adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 188 Small craft, in collaboration with the
European Committee for Standardization (CEN) Technical Committee CEN/TC 464, Small Craft, in accordance
with the Agreement on technical cooperation between ISO and CEN (Vienna Agreement).
This first edition cancels and replaces ISO/TS 23625:2021, which has been technically revised.
The main changes are as follows:
— a terminological entry for “audible alarm” has been added;
— requirements to comply with IEC 62619 and IEC 62620 have been added;
— EMC requirements for BMS have been added;
— Annex A has been extended;
— Annexes B and C have been added.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.

iv
International Standard ISO 23625:2025(en)
Small craft — Lithium-ion batteries
WARNING — Lithium-ion batteries used in direct current (DC) electrical systems on boats that
operate at potentials of 60 V or higher have additional safety requirements not addressed by this
document. Refer to the battery manufacturer’s recommendations.
1 Scope
This document specifies requirements and recommendations for the selection and installation of lithium-
ion batteries for boats, as well as requirements for the safety information provided by the manufacturer.
This document is applicable to lithium-ion batteries and battery systems with a capacity greater than
500 Wh used on small craft for providing power for general electrical loads and/or to electric propulsion
systems. It is primarily intended for manufacturers and battery installers.
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.
ISO 8846, Small craft — Electrical devices — Protection against ignition of surrounding flammable gases
ISO 13297, Small craft — Electrical systems — Alternating and direct current installations
ISO 25197, Small craft — Electrical/electronic control systems for steering, shift and throttle
IEC 60529, Degrees of protection provided by enclosures (IP Code)
IEC 62619, Secondary cells and batteries containing alkaline or other non-acid electrolytes — Safety
requirements for secondary lithium cells and batteries, for use in industrial applications
IEC 62620, Secondary cells and batteries containing alkaline or other non-acid electrolytes — Secondary lithium
cells and batteries for use in industrial applications
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
ampere interrupt capacity
AIC
maximum current a circuit breaker or fuse is rated to safely interrupt at a specific voltage
3.2
battery
collection of cells (3.7) wired in series (or series/parallel) and constituting a single physical unit

ISO 23625:2025(en)
3.3
battery bank
set of batteries (3.2) electrically connected (parallel/series) to increase capacity and/or voltage
3.4
battery capacity
C
amount of energy storage of the battery (3.2) from the manufacturer’s specified fully charged to discharged
voltage levels
Note 1 to entry: The battery capacity is expressed in ampere hours (Ah) at a nominal voltage or in watt hours (Wh).
Note 2 to entry: Ah and Wh capacity rating is at a given discharge rate or time.
3.5
battery management system
BMS
system designed to protect a lithium-ion battery (3.2) from potentially damaging events, such as overcharging
(3.19) or overdischarging (3.20) and high and low temperatures
3.6
battery system
battery (3.2) or batteries and all ancillary components
3.7
cell
fundamental building block that is inside a lithium-ion battery (3.2) 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
3.8
C rating
measure of battery (3.2) charge and discharge rating
Note 1 to entry: The C rating is expressed as a function of the rated ampere hours (Ah) battery capacity (3.4).
EXAMPLE A 100 Ah battery charged or discharged at 100 A is a 1C rate.
3.9
contactor
relay/switch controlled by the battery management system (3.5)
3.10
disconnect device
switch controlled by the battery management system (3.5) which disconnects a battery (3.2) or battery bank
(3.3) from charge and discharge sources, and other batteries or battery banks
3.11
high voltage cutout
HVC
battery management system's (3.5) response to a high voltage event (3.12) that protects the battery (3.2)
from overcharging (3.19)
3.12
high voltage event
HVE
condition where a cell (3.7) has been charged to a voltage above the manufacturer’s cell maximum voltage limit

ISO 23625:2025(en)
3.13
low voltage cutout
LVC
battery management system's (3.5) response to a low voltage event (3.14) that protects the battery (3.2) from
overdischarging (3.20)
3.14
low voltage event
LVE
condition where a cell (3.7) has been discharged beyond the cell manufacturer’s cell low voltage limit
3.15
high temperature cut-off
HTC
battery management system’s (3.5) response to a high temperature event (3.16)
3.16
high temperature event
HTE
condition where a cell (3.7), parallel string or bank has a temperature above the manufacturer’s maximum
cell temperature limit
3.17
low temperature cut-off
LTC
battery management system’s (3.5) response to a low temperature event (3.18)
3.18
low temperature event
LTE
condition where a cell (3.7), parallel string or bank has a temperature below the manufacturer’s minimum
cell temperature limit
3.19
overcharging
charging a cell (3.7) above the cell manufacturer’s upper cell voltage limit, which can result in damage to the cell
Note 1 to entry: Overcharging can result in thermal runaway (3.24) or damage to the battery (3.2) or cells.
3.20
overdischarging
discharging a battery (3.2) or cell (3.7) below the manufacturer’s minimum cell voltage limit
Note 1 to entry: Overdischarging can result in damage to the battery or cells and can include cell polarity reversal.
Note 2 to entry: Subsequent charging after overdischarging can result in thermal runaway (3.24).
3.21
readily accessible
capable of being reached quickly and safely for effective use under emergency conditions without the use of tools
3.22
safe operating limits
SOL
set of voltage, temperature and other parameters, within which the battery (3.2) is intended to be operated
and which, if exceeded, initiates a battery management system (3.5) response to correct the problem or to
shut the battery down
ISO 23625:2025(en)
3.23
state of charge
SOC
indication of the amount of usable capacity available in the battery (3.2)
Note 1 to entry: SOC is expressed as a percentage.
EXAMPLE 0 % = empty; 100 % = full.
3.24
thermal runaway
potentially dangerous and self-propagating battery (3.2) heating condition that can occur within a cell (3.7)
or cells
3.25
watertight
constructed so that water will not enter the enclosure
Note 1 to entry: Water integrity specifications can be found in IEC 60529.
3.26
weatherproof
constructed or protected so that exposure to the weather will not interfere with successful operation
Note 1 to entry: Water integrity specifications can be found in IEC 60529.
3.27
audible alarm
device with a sound pressure measured 1 m from the command station of at least 75 dB(A), but not greater
than 85 dB(A)
4 System design requirements
4.1 Lithium-ion batteries and their systems shall be installed in accordance with the requirements of
ISO 13297.
NOTE Lithium-ion batteries are not subject to routine electrolyte leakage or routine release of gas, therefore
requirements regarding electrolyte containment and routine gas ventilation cannot apply to lithium-ion battery
installations.
4.2 Lithium-ion battery systems shall be installed in accordance with the battery manufacturer’s
recommendations.
4.3 All battery system designs shall be done in a way that ensures that all installed lithium-ion batteries
are kept within the battery manufacturer’s specified SOL.
4.4 There shall be a BMS installed to control all installed lithium-ion batteries and maintain the battery
manufacturer’s specified SOL.
4.5 All battery systems shall have a BMS to provide for battery cut-off if hazardous conditions exist.
NOTE 1 A BMS can be external or internal to the battery.
NOTE 2 In the event of an individual BMS that disconnects, battery bank capacity can be reduced with no
notification to the vessel operator.
4.6 Batteries shall meet the requirements of IEC 62619 and IEC 62620.

ISO 23625:2025(en)
4.7 The battery system shall be sized in accordance with the application and the battery manufacturer’s
defined operating limits, and with the appropriate C rating listed in the battery specifications.
4.8 Output control from charging sources shall be within the battery manufacturer’s specified ranges.
4.9 If a shut-down condition is approaching for propulsion systems or other critical system (equipment
vital to safety), a BMS or system shall notify the operator with a visual and/or audible alarm, clearly
perceptible from the main helm position, prior to disconnecting the battery from the DC system.
4.10 Batteries of different chemistries shall not be connected in series. A means shall be provided to prevent
overcurrent conditions when connecting in parallel.
4.11 Multiple contactors are permitted (HVC, LVC, plus main), each providing specific protection from high
voltage, low voltage and load isolation. A single contactor is permitted, if the control system provides for
protection from all conditions.
4.12 On installations greater than 1 500 Wh when used for propulsion, the battery system shall be capable
of providing a state of health of the battery sy
...