prEN IEC 63056-1:2026

• Status: Not Published
• Publication Date: 16-Jan-2028
• ICS: 29.220.30 - Alkaline secondary cells and batteries
• Technical Committee: CLC/TC 21X - Secondary cells and batteries
• Current Stage: 4060 - Enquiry results established and sent to TC, SR, BTTF - Enquiry
• Start Date: 18-Sep-2026
• Completion Date: 18-Sep-2026
• Ref Project: oSIST prEN IEC 63056-1:2026 - Secondary cells and batteries containing alkaline or other non-acid electrolytes - Safety requirements for secondary lithium cells and batteries for use in electrical energy storage systems - Part 1: Intended for installations that provide additional safeguards

• Revises: EN IEC 63056:2020/AC:2021-07 - Secondary cells and batteries containing alkaline or other non-acid electrolytes - Safety requirements for secondary lithium cells and batteries for use in electrical energy storage systems
• Effective Date: 27-Feb-2024
• Revises: EN IEC 63056:2020 - Secondary cells and batteries containing alkaline or other non-acid electrolytes - Safety requirements for secondary lithium cells and batteries for use in electrical energy storage systems
• Effective Date: 27-Feb-2024

Overview

prEN IEC 63056-1:2026 sets out safety requirements for secondary lithium cells and batteries containing alkaline or other non-acid electrolytes, specifically for use in stationary electrical energy storage systems (EESS) where additional safeguards are provided. This standard, published by the CLC/IEC, defines product safety benchmarks for installations intended to provide supplementary protective measures, such as battery rooms or enclosures equipped with fire suppression, ventilation, or gas detection. It is a critical document for manufacturers, system integrators, and safety professionals involved with lithium-ion stationary storage applications, including grid support, emergency power, telecommunication backup, and industrial uses.

Key Topics

• Scope of Application: Focuses on secondary lithium cells and batteries with a maximum voltage of 1500 V DC, excluding portable systems and those below 500 Wh.
• Installation Requirements: Applies to battery systems installed in locations with additional safety measures (dedicated rooms/enclosures), or where risks are mitigated by structural safeguards (e.g., walls, vents, physical separation).
• Hazard Consideration: Addresses electrical, thermal, mechanical, and chemical risks, such as electric shock, short circuits, fire, explosion, smoke, and electrolyte leakage.
• Design and Manufacture: Enforces quality of components (cells, wires, connectors) and ensures compliance with international standards. Requires robust battery management systems (BMS) for monitoring, protection, and control (overcharge, overdischarge, temperature).
• Testing Procedures: Mandates rigorous routine and type tests, including verification for resistance to heat, impact, electrical insulation, short circuit protection, drop and vibration, and electromagnetic compatibility (EMC).
• Labeling and Documentation: Requires clear safety information, labeling, and user instructions for installation, operation, and maintenance.
• Protection Features: Installation designs must include accessible and lockable disconnect means for circuits with hazardous voltages, and systems must prevent user exposure to live parts.

Applications

This standard plays a fundamental role in assuring safety, reliability, and sustainable operation in the following applications:

• Electrical Energy Storage Systems (EESS): For grid-connected and off-grid configurations such as utility-scale, renewable integration, and load balancing.
• Telecommunications: Backup power for network operations, ensuring continuity during outages.
• Emergency Lighting and Alarm Systems: Reliable energy sources for central emergency installations.
• Uninterruptible Power Supply (UPS): Stable backup for critical infrastructure.
• Industrial Engine Starting: Stationary lithium batteries for engine cranking in industrial environments.
• Photovoltaic (PV) Storage: Solar energy storage in commercial or residential applications, integrating batteries with PV systems.

Related Standards

To ensure comprehensive safety and interoperability, prEN IEC 63056-1:2026 references and complements several international standards, including:

• IEC 62619 - General safety requirements for secondary lithium cells and batteries used in industrial applications.
• IEC 62485-5 - Safe operation of stationary lithium-ion batteries.
• IEC 62368-1 - General equipment safety in audio/video and ICT infrastructure.
• IEC 60529 - Degrees of protection provided by enclosures (IP Code).
• IEC 60364 series & IEC 61140 - Protection against electric shocks in installations.
• IEC 61000-6-7 - Electromagnetic compatibility (EMC) for safety-related systems.
• UL9540A - Test methods for evaluating thermal runaway fire propagation in battery energy storage systems.

These related standards help manufacturers, installers, and regulators align with best practices for battery safety, energy storage system reliability, and risk mitigation across diverse environments and regulatory regimes.

---

By implementing the requirements of prEN IEC 63056-1:2026 in energy storage installations, stakeholders can achieve a high level of safety, meet legal obligations, gain market acceptance, and support the transition to sustainable energy systems.

SLOVENSKI STANDARD
01-september-2026
Sekundarni členi in baterije z alkalnimi ali drugimi nekislinskimi elektroliti -
Varnostne zahteve za sekundarne litijeve člene in baterije za uporabo v električnih
napravah za shranjevanje energije - 1. del: Namenjene za instalacije, ki
zagotavljajo dodatne varnostne ukrepe
Secondary cells and batteries containing alkaline or other non-acid electrolytes - Safety
requirements for secondary lithium cells and batteries for use in electrical energy storage
systems - Part 1: Intended for installations that provide additional safeguards
Sekundärzellen und -batterien mit alkalischen oder anderen nicht-säurehaltigen
Elektrolyten - Sicherheitsanforderungen für Lithium-Sekundärzellen und -batterien für die
Verwendung in elektrischen Energiespeichersystemen
Accumulateurs alcalins et autres accumulateurs à électrolyte non acide - Exigences de
sécurité pour les accumulateurs au lithium pour utilisation dans des systèmes de
stockage d’énergie électrique
Ta slovenski standard je istoveten z: prEN IEC 63056-1:2026
ICS:
29.220.30 Alkalni sekundarni členi in Alkaline secondary cells and
baterije batteries
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

21A/983/CDV
COMMITTEE DRAFT FOR VOTE (CDV)
PROJECT NUMBER:
IEC 63056-1 ED1
DATE OF CIRCULATION: CLOSING DATE FOR VOTING:
2026-06-26 2026-09-18
SUPERSEDES DOCUMENTS:
21A/933/CD, 21A/954A/CC
IEC SC 21A : SECONDARY CELLS AND BATTERIES CONTAINING ALKALINE OR OTHER NON-ACID ELECTROLYTES
SECRETARIAT: SECRETARY:
France Mr Jean-Marie Bodet
OF INTEREST TO THE FOLLOWING COMMITTEES: HORIZONTAL FUNCTION(S):

TC 21,TC 120
ASPECTS CONCERNED:
Safety
SUBMITTED FOR CENELEC PARALLEL VOTING NOT SUBMITTED FOR CENELEC PARALLEL VOTING
Attention IEC-CENELEC parallel voting
The attention of IEC National Committees, members of
CENELEC, is drawn to the fact that this Committee Draft
for Vote (CDV) is submitted for parallel voting.
The CENELEC members are invited to vote through the
CENELEC online voting system.
This document is still under study and subject to change. It should not be used for reference purposes.
Recipients of this document are invited to submit, with their comments, notification of any relevant patent rights of
which they are aware and to provide supporting documentation.
Recipients of this document are invited to submit, with their comments, notification of any relevant “In Some
Countries” clauses to be included should this proposal proceed. Recipients are reminded that the CDV stage is
the final stage for submitting ISC clauses. (SEE AC/22/2007 OR NEW GUIDANCE DOC).

TITLE:
Secondary cells and batteries containing alkaline or other non-acid electrolytes – Safety
requirements for secondary lithium cells and batteries for use in electrical energy storage
systems – Part 1: Intended for installations that provide additional safeguards

PROPOSED STABILITY DATE: 2030
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NOTE FROM TC/SC OFFICERS:
The split of the initial standard IEC 63056 into two parts was approved by the National Committees
(21/975/RQ) on 2026-03-06.
IEC 63056, Edition 2, therefore becomes IEC 63056-1.

The title for IEC 63056-1 is as follows:

First proposal (21A/975/RQ):
Secondary cells and batteries containing alkaline or other non acid electrolytes – Safety requirements
for secondary lithium cells and batteries for use in electrical energy storage systems – Battery systems
intended to be safe with dedicated battery rooms

Updated proposal, based on consensus reached by the Project Team for CDV:
Secondary cells and batteries containing alkaline or other non acid electrolytes – Safety requirements
for secondary lithium cells and batteries for use in electrical energy storage systems – Part 1: Intended
for installations that provide additional safeguards

The proposed CDV was presented to and approved by the experts of WG5 during the IEC SC 21A WG5
virtual meeting held on 2026 04 23.

Link to Committee Draft for Vote (CDV) online document:
Click here
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IEC CDV 63056-1 © IEC 2026
CONTENTS
Contact . 3
CONTENTS . 4
FOREWORD . 6
INTRODUCTION . 8
1 Scope . 9
2 Normative references . 10
3 Terms and definitions . 11
4 Parameter measurement tolerances . 14
5 General safety considerations and requirements during design phase . 15
5.1 General . 15
5.2 Components, connections and wiring . 16
5.3 Protection against electrical shock . 17
5.4 Spacing of circuits . 18
5.5 Enclosures . 18
5.6 Functional safety . 19
5.7 Thermal management . 20
6 Test conditions . 20
6.1 General . 20
6.2 Basic requirement . 20
6.3 Test items . 20
6.4 Charging procedures for test purposes . 22
7 Tests description . 22
7.1 Resistance to abnormal heat . 22
7.2 Electrical insulation . 22
7.3 Protective bonding path continuity . 23
7.4 Dielectric withstand . 23
7.5 Impulse withstand . 24
7.6 Protection against short circuit and installation . 24
7.7 Protection for reverse connection . 25
7.8 Overdischarge control of voltage . 26
7.9 Overdischarge control of current . 27
7.10 Electromagnetic compatibility (EMC) - Immunity . 27
7.11 Drop . 29
7.11.1 General . 29
7.11.2 Whole drop . 29
7.11.3 Edge and corner drop . 30
7.12 External forces . 31
7.12.1 Deflection . 31
7.12.2 Impact . 32
7.13 Thermal management . 33
7.14 Pressure strenght . 35
7.15 Thermal propagation protection . 35
8 Informations for Safety and Use . 37
8.1 Safety labels . 37
8.2 Instruction . 37
9 Marking and designation . 39
IEC CDV 63056-1 © IEC 2026
Annex A (normative) Form of documentation for battery system . 40
Annex B (informative) Wiring, connections and supply . 43
Bibliography . 44

Figure 1 – IEC 62619 as umbrella standard to various industrial applications . 8
Figure 2 – Scope example of IEC 63056 with single battery system . 9
Figure 3 – Scope example of IEC 63056 with multiple battery systems in parrallel . 10
Figure 4 – Setup example of Electromagnetic compatibility (EMC) - Immunity testing . 28
Figure 5 – Impact location . 30
Figure 6 – Configuration for the shortest edge drop test . 31
Figure 7 – Configuration for the corner drop test . 31
Figure 8 – Impact test using steel ball . 33

Table 1 – Type and routine test items . 21
Table 2 – Drop test method and condition . 29
Table B.1 – Wiring, connections and supply, as addressed in IEC 62368-1:2023 [6] . 43

IEC CDV 63056-1 © IEC 2026
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
Secondary cells and batteries containing alkaline or other non-acid
electrolytes – Safety requirements for secondary lithium cells and
batteries for use in electrical energy storage systems –
Part 1: Intended for installations that provide additional safeguards

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
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2) The formal decisions or agreements of IEC on technical matters express, as nearly as
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5) IEC itself does not provide any attestation of conformity. Independent certification bodies
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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
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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) IEC draws attention to the possibility that the implementation of this document may involve
the use of (a) patent(s). IEC takes no position concerning the evidence, validity or applicability
IEC CDV 63056-1 © IEC 2026
of any claimed patent rights in respect thereof. As of the date of publication of this document,
IEC [had/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 https://patents.iec.ch.
IEC shall not be held responsible for identifying any or all such patent rights.
IEC 63056 has been prepared by subcommittee 21A: Secondary cells and batteries containing
alkaline or other non-acid electrolytes, of IEC technical committee 21: Secondary cells and
batteries. It is an International Standard.
This second edition cancels and replaces the first edition published in 2020. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) .;
The text of this International Standard is based on the following documents:
Draft Report on voting
XX/XX/FDIS XX/XX/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 [change
language if necessary].
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 http://www.iec.ch/members_experts/refdocs. The main document types developed by IEC
are described in greater detail at http://www.iec.ch/publications.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under http://webstore.iec.ch in the data related to
the specific document. At this date, the document will be
– reconfirmed,
– withdrawn, or
– revised.
IEC CDV 63056-1 © IEC 2026
INTRODUCTION
This document specifies safety requirements for secondary lithium cells and batteries covered
by the scope in Clause 1, and intended for use in stationary electrical energy storage systems.
Basic safety requirements for the secondary lithium cells and batteries used in industrial
applications, including stationary application, are included in IEC 62619 as shown in Figure 1.

Figure 1 – IEC 62619 as umbrella standard to various industrial applications
This document provides additional or specific requirements for batteries intended to be used
with stationary electrical energy storage systems.
Since this document covers battery systems for use in various stationary electrical energy
storage systems, it includes those requirements which are common and minimum to a stationary
electrical energy storage systems application.
IEC CDV 63056-1 © IEC 2026
1 Scope
This document specifies requirements and tests for the product safety of secondary lithium cells
and batteries used in stationary electrical energy storage systems (Figure 2 and Figure 3) with
a maximum DC voltage of 1500 V.
This document applies to battery system intended for installation only accessible to electrically
skilled person and :
– In dedicated technical rooms or enclosures (such as buildings, cabinets or containers) that
are equipped with additional safety features (such as fire suppression, ventilation, gas
detection) or thermal management systems. And, or,
– In installations where the consequences of fire and/or deflagration are mitigated through
safeguards provided by the installation (e.g. distance, walls, enclosures and explosion relief
vents).
NOTE Whenever this standard makes reference to ambient condition, this reference means the ambient condition
of the battery system is inside the enclosure or room. The auxiliary equipment(s) in the enclosure or room needs to
ensure that these ambient conditions are met under the external (i.e. outdoor) ambient conditions.
Examples of battery systems applications that are within the scope of this document are, but
not limited to:
– telecommunications,
– central emergency lighting and alarm systems,
– stationary engine starting,
– photovoltaic and grid-connected storage systems,
– large or utility energy storage (on-grid/off-grid),
– uninterruptible power supplies (UPS)
This document does not apply to portable systems, or battery system below 500 Wh, which are
covered by IEC 61960-3 [1].
Figure 2 – Scope example of IEC 63056 with single battery system
IEC CDV 63056-1 © IEC 2026
Figure 3 – Scope example of IEC 63056 with multiple battery systems in parrallel
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 60050-482, International Electrotechnical Vocabulary (IEV) - Part 482: Primary and
secondary cells and batteries (available at http://www.electropedia.org/)
IEC 60364-4-41:2005, Low-voltage electrical installations - Part 4-41: Protection for safety -
Protection against electric shock
IEC 60529:1989, Degrees of protection provided by enclosures (IP Code)
IEC 60664-1:2020, Insulation coordination for equipment within low-voltage supply system -
Part 1: Principles, requirements and tests
IEC 60695-10-2, Fire hazard testing - Part 10-2: Abnormal heat - Ball pressure test method
IEC 60695-11-10, Fire hazard testing - Part 11-10: Test flames - 50 W horizontal and vertical
flame test methods
IEC 60730-1:2022, Automatic electrical controls - Part 1: General requirements
IEC 61140:2016, Protection against electric shock - Common aspects for installation and
equipment
IEC 61140, Protection against electric shock - Common aspects for installation and equipment
IEC CDV 63056-1 © IEC 2026
IEC 61508, Functional safety of electrical/electronic/programmable electronic safety-related
systems
IEC 62368-1:2023, Audio/video, information and communication technology equipment - Part
1: Safety requirements
IEC 62477-1:2022, Safety requirements for power electronic converter systems and equipment
- Part 1: General
IEC 62485-5:2020, Safety requirements for secondary batteries and battery installations - Part
5: Safe operation of stationary lithium ion batteries
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 62619:2022, 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 62620:2014, Secondary cells and batteries containing alkaline or other non-acid
electrolytes - Secondary lithium cells and batteries for use in industrial applications
ISO/IEC Guide 51, Safety aspects - Guidelines for their inclusion in standards
IEC61000-6-7, Electromagnetic compatibility (EMC) - Part 6-7: Generic standards - Immunity
requirements for equipment intended to perform functions in a safety-related system (functional
safety) in industrial locations
UL9540A, Test Method for Evaluating Thermal Runaway Fire Propagation in Battery Energy
Storage Systems
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 60050-482, ISO/IEC
Guide 51, and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
– IEC Electropedia: available at http://www.electropedia.org/
– ISO Online browsing platform: available at http://www.iso.org/obp
3.1
safety
freedom from unacceptable risk
3.2
risk
combination of the probability of occurrence of harm and the severity of that harm
3.3
harm
physical injury or damage to the health of people or damage to property or to the environment
IEC CDV 63056-1 © IEC 2026
3.4
hazard
potential source of harm
3.5
exposure
receptors near the electrical energy storage system potentially sensitive to fire hazards (e.g. lot
lines, public ways, buildings, flammable materials, explosive materials, vehicle)
3.6
intended use
use of a product, process or service in accordance with specifications, instructions and
information provided by the supplier
3.7
reasonably foreseeable misuse
use of a product, process or service in a way which is not intended by the supplier, but which
may result from readily predictable human behaviour
3.8
secondary lithium cell
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.
3.9
cell block
group of cells connected together in parallel configuration with or without protective devices
(e.g. fuse or positive temperature coefficient 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.
3.10
module
group of cells connected together in a series and/or parallel configuration with or without
protective devices (e.g. fuse or positive temperature coefficient device) and monitoring circuitry
Note 1 to entry: The module is considered as internal part of battery pack and not intended to be serviced during
maintenance of the battery system.
3.11
battery pack
energy storage device which comprises one or more cells or modules electrically connected
and has monitoring circuitry which provides information (e.g. cell voltage) to a battery system
to influence the battery's safety, performance and/or service life
Note 1 to entry: It incorporates a protective housing and is provided with terminals or other interconnection
arrangement.
3.12
battery system
battery
system which comprises one or more cells, modules or battery packs and has a battery
management system capable of controlling current in case of overcharge, overcurrent,
overdischarge, and overheating
IEC CDV 63056-1 © IEC 2026
Note 1 to entry: The battery system may be connected or installed with auxiliary systems like chiller, air conditioner,
fire suppression system, dehumidifier, gas ventilation system, distribution panels… These systems are considered
parts of the electrical energy storage system, so not covered by this standard, unless they are included in the BMS
(3.13) or module enclosure. If external components, only interfaces from such systems to the battery itself are in the
scope (water cooling inlet on module, electrical input/output…)
3.13
battery management system
BMS
set of protection functions associated with a battery to prevent overcharge, overcurrent, over -
temperature, under-temperature and, if applicable, overdischarge and which monitors and/or
manages its state, calculates secondary data, reports that data and/or controls its environment
to influence the battery's safety, performance and/or service life
Note 1 to entry: Overdischarge cutoff is not mandatory if there is an agreement between the cell manufacturer and
the customer.
Note 2 to entry: The function of the BMS (3.13) can be assigned to the battery pack or to equipment that uses the
battery.
Note 3 to entry: The BMS (3.13) can be divided, and it can be found partially in the battery pack and partially on
the equipment that uses the battery.
Note 4 to entry: The BMS (3.13) is sometimes also referred to as a BMU (battery management unit).
Note 5 to entry: This note applies to the French language only.
3.14
power electronic converter system
PECS
one or more power electronic converters intended to work together with other equipment
[SOURCE: IEC 62477-1:2022]
3.15
leakage
visible escape of liquid such as but not limited to electrolyte from cell or coolant from cooling
system
3.16
venting
release of excessive internal pressure from a cell, module, battery pack, or battery system in a
manner intended by design to prevent rupture or explosion
3.17
rupture
mechanical failure of a cell container or battery case induced by an internal or external cause,
resulting in exposure or spillage but not ejection of materials
3.18
explosion
failure that occurs when a cell container or battery case opens violently, and solid components
are forcibly expelled
Note 1 to entry: Liquid, gas, and smoke may be erupted.
3.19
fire
emission of flames from a cell, module, battery pack, or battery system
IEC CDV 63056-1 © IEC 2026
3.20
smoke
visible suspension of solid and/or liquid particules in gases resulting from incomplete
combustion, typically emitted from a burning substance
3.21
hazardous voltage
voltage exceeding 120 V DC or 50 V AC
[SOURCE: IEC 62368-1 (class ES2) and IEC 61140]
3.22
rated capacity
capacity value of a cell or battery determined under specified conditions and declared by the
manufacturer
Note 1 to entry: The rated capacity is the quantity of electricity C Ah (ampere-hours) declared by the manufacturer,
n
which a single cell or battery can deliver during an n-hour period when charging, storing and discharging under the
conditions specified in IEC 62620:2014, 6.3.1.
[SOURCE: IEC 60050-482, 482-03-15, modified - "battery" has been replaced by "cell or
battery" and Note 1 to entry has been added.]
3.23
peak discharge current
current exceeding the rated current of the cell, cell block and other components that is
permissible for a limited time as specified by the manufacturers of the cell, cell block and other
components
3.24
enclosure
housing of uninsulated live parts affording the type and degree of protection suitable for the
intended application (IEC 60050)
3.25
routine test
test to which each individual device is subjected during or after manufacture to ascertain
whether it complies with certain criteria
[SOURCE: IEC 60050-411:1996, 411-53-02, modified – The word "machine" has been replaced
by "device".]
4 Parameter measurement tolerances
The overall accuracy of controlled or measured values, relative to the specified or actual
parameters, shall be within the following tolerances:
a) ±0,5 % for voltage;
b) ±1 % for current;
c) ±2 °C for temperature;
d) ±0,1 % for time;
e) ±1 % for mass;
f) ±1 % for dimensions.
These tolerances comprise the combined accuracy of the measuring instruments, the
measurement techniques used, and all other sources of error in the test procedure.
IEC CDV 63056-1 © IEC 2026
Unless mentioned otherwise, these tolerances refer to external test equipment, i.e. they do not
refer to the inaccuracy of the sensors that are permanent parts of the battery system.
The details of the instrumentation used shall be provided in any report of results.
5 General safety considerations and requirements during design phase
5.1 General
Battery systems and the cells they contain shall comply with the applicable general safety
considerations of IEC 62619:2022 Clause 5. Within the standard temperature range, cells can
be charged at the maximum charge current, which is specified from a safety point of view.
Lithium-ion cells shall always be operated within the operating region values and the storage
conditions specified by the manufacturer.
The safety of cells and battery systems requires the consideration of two sets of applied
conditions:
– intended use,
– reasonably foreseeable misuse.
Cells and battery systems shall be designed and constructed that they are safe under conditions
of both intended use and reasonably foreseeable misuse.
It is expected that cells and battery systems subjected to intended use shall not only be safe
but shall continue to be functional in all respects. It is also expected that cells or battery systems
subjected to misuse may fail to function. However, even if such a situation occurs, they shall
not present any significant hazards.
Potential hazards which are the subject of this document are:
– Electrical hazards: direct or indirect electrical shock
– Thermal hazards: fire, arc flash, hot surfaces
– Mechanical hazards: explosion, rupture
– Chemical hazards: venting gas, smoke, electrolyte leakage
Usage of the battery system in a electrical energy storage system with additional auxiliary
systems can cause additional hazards such as collapsing, release of fire suppression agent,
mechanical hazards from rotating parts or electrical hazards from auxiliary systems. These
hazards are not covered in this standard and need to be considered at the installation level
according to appropriate standards such as IEC 62485-5:2020 or IEC 62933-5-2:2025 [2].
Conformity of the battery system itself is checked by the tests in accordance with this standard
and supported by appropriate standards such as listed in Clause 2. Nevertheless, hazards that
cannot be prevented and mitigated by type testing and routine testing of the equipment and that
thereby require safety measures on the installation level shall be declared according to the
requirements of 8.2.
Where this standard allows for different options, the user and the manufacturer of the battery
system should agree for the desired option based on the conditions of the electrical energy
storage system. The chosen option shall be documented by the manufacturer according to 8.2.
Moving parts that have potential to cause human injuries shall be applied appropriate design
and necessary measures in order to reduce the risk of injuries, including those that may be
incurred during installation while cells or battery systems are being incorporated into equipment.
IEC CDV 63056-1 © IEC 2026
5.2 Components, connections and wiring
Each critical component used within battery system (e.g. cells, insulated wires, contactors,
fuses, sensors, insulators, plugs and receptacles) shall be rated at the intended use (e.g.
voltage, rated current, peak discharge current, temperature and humidity, insulation, altitude,
breaking current capabilities) and evalutated based on relevant international standards for their
safety compliance.
Peak discharge current exceeding the declared maximum discharging current is permitted for
a limited time if all the following condition are met:
– The peak discharge current does not exceed the maximum discharge current of cells or cell
blocks.
– The components (e.g. contactors, connectors) are evaluated for the peak discharge current
and time exceeding the declared maximum discharge current of the battery system.
– Additional overdischarge control of current is implemented to limit time of peak discharge
current exceeding the declared maximum discharge current.
See Annex B for informative material related to wiring, connections and supply.
Plugs, connectors and terminals should be designed to avoid miswiring, such as reverse
connection and short circuit.
Thermal limits of critical components in operation shall be checked according to 7.13.
Pipes and connections, for liquid cooling battery systems, shall be rated over the maximum
operational pressure. The pressure tightness shall be checked according to 7.14.
The battery system and its critical components shall also withstand the required dielectric
voltage and rated impulse withstand voltage test between circuit, intended for the end use
application (see 5.4).
Component of modules intended for series connection shall be designed or rated at the
maximum voltage of the intended battery system. The maximum number of series shall be
declared (see 8.2).
For any incoming or outgoing circuit of the battery system involving hazardous voltage, a
disconnect means shall be included to isolate the battery system from external devices, such
as PECS or other battery system in parallel. The disconnect means shall be accessible and
lockable (such as defined in IEC 60947-1:2020 [3]) in open circuit position to prevent
unintended operation. It shall consist in one or more device rated to ensure the safe opening
underload conditions. In the case of more than one device, labeling shall indicate the restriction
for opening under load capabilities (see 8.1).
NOTE 1 Disconnect device behind door are considered accessible.
A serial connection of cells or cell blocks shall not exceed 240 V DC nominal without
disconnection means (terminal with plug and socket outlet or manual switch disconnector only),
opening under load condition is not required.
NOTE 2 240 V DC limit is intended to reduce arc flash energy for maintenance or installation purposes.
Battery systems circuit involving hazardous voltage shall not require any operation involving
uninsulated live parts during operation and disconnection.
Uninsulated live part shall be mechanically secured.
IEC CDV 63056-1 © IEC 2026
In the case of battery system involving liquid cooling, leakage of coolant (e.g. interfaces and
connectors with crimped or screwed tightening) shall not introduce any hazard. When
evaluating, all characteristics of the coolant shall be considered, such as but not limited to
electrical conductivity, flammability, corrosion, toxicity.
For liquid cooled battery system, the coolant should be properly managed and contained in
case of leakage. Leaked coolant shall be contained to prevent contamination of soil and
groundwater. If an external containment is required, the corresponding quantity and type of
coolant to be retained shall be specified in the documentation according to section 8.2.
5.3 Protection against electrical shock
The battery system shall be designed to ensure installation with protection against electrical
shock from hazardous voltage circuits including basic protection (against direct contact) and
fault protection (against indirect contact) according to IEC 60364-4-41:2005.
Basic protection of the battery system circuits shall be ensured by enclosure with a degree of
ingress protection according to 5.5 and:
– Basic insulation according to IEC 60364-4-41:2005 411 or,
– Double or reinforced insulation according to IEC 60364-4-41:2005 412.
The basic or reinforced insulation shall be designed (creepage and clearance distances from
non-carry current conductive parts to live parts) according to 5.4 and tested according to 7.4
and 7.5.
Guidance to determine if basic or reinforced insulation is suitable for the involved circuit(s) is
given in IEC 62477-1:2022 Table 2 and 3.
Fault protection of the battery system circuits shall be ensured by bonding all accessible non -
live conductive parts of the battery system to form an electrically conductive protective
equipotential bonding path.
Wires used in the protective equipotential bonding path shall be suitably protected against
mechanical or chemical damage (e.g. deformation, insulation rupture).
When sizing the protective equipotential bonding path (e.g. wires, busbar), the voltage rating
and fault current of all AC or DC sources of supply within the battery system shall be considered.
Guidance for sizing are provided in IEC 62477-1:2022 4.4.4.2.2.
A firmly secured metal to metal conductive connection is required to ensure durable electrical
continuity and mechanical strength. For example, thread locking sealant is not considered
acceptable for securing grounding connection. When painted surfaces are joined together,
masking paint, paint piercing methods or separate connection should be made to ensure reliable
contact.
The protective equipotential bonding path resistance is checked in test 7.3.
Regarding connection of the protective equipotential bonding path to the external protective
conductor from earth:
– When basic insulation is used for a circuit, the protective equipotential bonding path shall
be connected to earth by protective conductor according IEC 60364-4-41:2005 and shall not
incorporate a component that may open the circuit. The main grounding ter minal of the
battery system used for connection to protective conductor shall be identified according to
Clause 9.
– When reinforced insulation is used for a circuit, the grounding path shall not be connected
to a protective conductor. The battery system shall be identified according to Clause 9.
IEC CDV 63056-1 © IEC 2026
However, if the battery system has both basic insulation and reinforced insulation circuits,
provision for protective conductor may be made according to IEC 60364-4-41:2005 412.2.2.4.
For battery system with non-hazardous voltage circuits ( requirements for basic and fault
protection shall be according to IEC 60364-4-41:2005.
In accordance with the electrical circuit(s) insulation defined above, the corresponding
protective class(es) number(s) according to IEC 61140 shall be declared in Annex A according
to Clause 9.
5.4 Spacing of circuits
To avoid inadvertent short circuits and electrical hazard, the design of electrical insulation shall
ensure that clearances and creepage distances are securely and reliably maintained between:
– opposite polarity
– hazardous live parts to exposed conductive part
– and to others voltage circuits conductors
In accordance with IEC 62368-1:2023 (not exceeding 600 V) or IEC 60664-1:2020 (up to 1500
V DC) or IEC 62477-1:2022 (up to 1500 V DC) or IEC 62109, according to intended use for the
electrical energy storage system.
An insulation analysis shall be documented by the battery system manufacturer with:
– Circuits description with voltage category, selected rated impulse voltage, components
involved in circuit, type of insulation (e.g. basic and/or reinforced)
– OVC, PD and CTI level selected for each circuit.
– Clearance and creepage distances selected for each circuit.
The overvoltage category (OVC) of the supplies of the battery system (DC or AC) is determined
by the battery system manufacturer according to the connection type to the supply mains (see
information in IEC 60664-1:2020 4.3). If permanently connected to main supply, OVCIII shall
apply to the circuit but can be reduced OVCII with SPD or such an equipment that avoid
transient voltage. If the equipment is not part of the battery system, the corresponding
requirement shall be documented in accordance with 8.2.
The anticipated pollution degree (PD) shall be determined and declared considering end use
system enclosure protection against conductive or non-conductive dust, humidity,
condensation. Guidance for selection is given in IEC 60664-1:2020 4.5.
Wires of circuit operating at different voltages shall be secured to be in accordance with the
determined creepage and clearance, in any location, unless they are insulated at the highest
circuit voltage involved.
For battery system intended to be used in altitude over 2000 m, cor
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