IEC 62660-3:2022
(Main)Secondary lithium-ion cells for the propulsion of electric road vehicles - Part 3: Safety requirements
Secondary lithium-ion cells for the propulsion of electric road vehicles - Part 3: Safety requirements
IEC 62660-3:2022 specifies test procedures and acceptance criteria for safety performance of secondary lithium-ion cells and cell blocks used for propulsion of electric vehicles (EV) including battery electric vehicles (BEV) and hybrid electric vehicles (HEV). This document determines the basic safety performance of cells used in a battery pack and system under intended use and reasonably foreseeable misuse or incident, during the normal operation of the EV. The safety requirements of the cell in this document are based on the premise that the cells are properly used in a battery pack and system within the limits for voltage, current and temperature as specified by the cell manufacturer (cell operating region).
Eléments d'accumulateurs lithium-ion pour la propulsion des véhicules routiers électriques - Partie 3: Exigences de sécurité
L'IEC 62660-3:2022 spécifie les procédures d'essai et les critères d'acceptation en matière de performance de sécurité des éléments d'accumulateurs lithium-ion et des blocs d'éléments utilisés pour la propulsion des véhicules électriques (VE), y compris les véhicules électriques à batterie (VEB) et les véhicules électriques hybrides (VEH). Le présent document a pour objet de déterminer les performances de sécurité de base des éléments utilisés dans un groupe et système de batteries dans les conditions d'utilisation prévue et les mauvaises utilisations ou incidents raisonnablement prévisibles, pendant le fonctionnement normal du VE. Dans le présent document, les exigences de sécurité de l'élément s'appuient sur l'hypothèse selon laquelle les éléments sont correctement utilisés dans un groupe et système de batteries dans les limites de tension, de courant et de température spécifiées par le fabricant de l'élément (plage de fonctionnement de l'élément).
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IEC 62660-3 ®
Edition 2.0 2022-03
REDLINE VERSION
INTERNATIONAL
STANDARD
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inside
Secondary lithium-ion cells for the propulsion of electric road vehicles –
Part 3: Safety requirements
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IEC 62660-3 ®
Edition 2.0 2022-03
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
inside
Secondary lithium-ion cells for the propulsion of electric road vehicles –
Part 3: Safety requirements
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.220.20; 43.120 ISBN 978-2-8322-5348-9
– 2 – IEC 62660-3:2022 RLV © IEC 2022
CONTENTS
FOREWORD . 4
INTRODUCTION .
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 8
4 Test conditions . 10
4.1 General . 10
4.2 Measuring instruments . 10
4.2.1 Range of measuring devices . 11
4.2.2 Voltage measurement . 11
4.2.3 Current measurement . 11
4.2.4 Temperature measurements . 11
4.2.5 Other measurements . 12
4.3 Tolerance . 12
4.4 Test temperature Thermal stabilization . 13
5 Electrical measurement . 13
5.1 General charge conditions . 13
5.2 Capacity . 13
5.3 SOC adjustment . 13
6 Safety tests . 13
6.1 General . 13
6.2 Mechanical tests . 14
6.2.1 Vibration .
6.2.1 Mechanical shock . 14
6.2.2 Crush . 14
6.3 Thermal test . 15
6.3.1 High temperature endurance. 15
6.3.2 Temperature cycling . 16
6.4 Electrical tests . 16
6.4.1 External short-circuit . 16
6.4.2 Overcharge . 16
6.4.3 Forced discharge . 17
6.4.4 Internal short-circuit test . 17
Annex A (informative) Operating region of cells for safe use . 20
A.1 General . 20
A.2 Charging conditions for safe use . 20
A.2.1 General . 20
A.2.2 Consideration on charging voltage . 20
A.2.3 Consideration on temperature . 21
A.3 Example of operating region . 22
Annex B (informative) Explanation for the internal short-circuit test . 23
B.1 General concept . 23
B.2 Internal short-circuit caused by the particle contamination . 23
Annex C (normative) Alternative internal short-circuit test (6.4.4.2.2) . 25
C.1 General . 25
C.2 Test preparation and test set-up . 25
C.2.1 Preparation of cell before the test . 25
C.2.2 Test setup . 27
C.2.3 Preliminary test . 28
C.3 Test procedure . 29
C.4 Acceptance criteria . 29
Bibliography . 30
Figure 1 – Example of temperature measurement of cell . 12
Figure 2 – Example of crush test . 15
Figure A.1 – An example of operating region for charging of typical lithium-ion cells . 22
Figure A.2 – An example of operating region for discharging of typical lithium-ion cells . 22
Figure C.1 – Example of case thinning . 25
Figure C.2 – Example of thinning tool . 26
Figure C.3 – Example of removing hard case . 26
Figure C.4 – Example of hard case removal method during cell manufacturing . 26
Figure C.5 – Example of fixation of cell . 27
Figure C.6 – Test setup image for voltage measurement . 27
Figure C.7 – Example of abrupt voltage drop . 28
Table B.1 – Examples of the internal short-circuit of cell . 24
– 4 – IEC 62660-3:2022 RLV © IEC 2022
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
SECONDARY LITHIUM-ION CELLS FOR THE PROPULSION
OF ELECTRIC ROAD VEHICLES –
Part 3: Safety requirements
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
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rights. IEC shall not be held responsible for identifying any or all such patent rights.
This redline version of the official IEC Standard allows the user to identify the changes made to
the previous edition IEC 62660-3:2016. A vertical bar appears in the margin wherever a change
has been made. Additions are in green text, deletions are in strikethrough red text.
IEC 62660-3 has been prepared by IEC technical committee 21: Secondary cells and batteries.
It is an International Standard.
This second edition cancels and replaces the first edition published in 2016. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) The new method for the internal short-circuit test has been added in 6.4.4.2.2 and Annex C,
as an alternative option to the test in 6.4.4.2.1.
b) The vibration test has been deleted.
c) The test conditions of overcharge (6.4.2.2) have been partially revised.
The text of this International Standard is based on the following documents:
Draft Report on voting
21/1133/FDIS 21/1137/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.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/standardsdev/publications.
A list of all parts in the IEC 62660 series, published under the general title Secondary lithium-ion
cells for the propulsion of electric road vehicles, 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.
– 6 – IEC 62660-3:2022 RLV © IEC 2022
INTRODUCTION
The electric road vehicles (EV) including hybrid and plug-in hybrid electric vehicles are
beginning to diffuse in the global market with backing from global concerns on CO reduction
and energy, recent advances in technology and cost reduction. This has led to a rapidly
increasing demand for high-power and high-energy density traction batteries represented by
lithium-ion batteries.
For securing a basic level of quality of lithium-ion batteries for automotive applications, relevant
international standards, i.e. IEC 62660-1, IEC 62660-2, ISO 12405-1 and ISO 12405-2, have
been published. These standards specify the performance, reliability and abuse testing of
lithium-ion battery cells, packs and systems for EV applications. Further, in the light of
increasing concerns on the safety of lithium-ion batteries and demand for a referenceable
international standard, safety requirements for lithium-ion battery packs and systems are
defined in ISO 12405-3. Regulations, such as UN ECE R100, are also being revised that include
acceptance criteria for rechargeable energy storage systems of EVs.
It is essential to specify the safety criteria at cell level in this standard, in order to secure the
basic safety level of cells which differ in performance and design, and are applied to a variety
of types of packs and systems. For automobile applications, it is important to note the design
diversity of automobile battery packs and systems, and specific requirements for cells and
batteries corresponding to each of such designs. Based on these facts, the purpose of this
standard is to provide a basic level of safety test methodology and criteria with general
versatility, which serves a function in common primary testing of lithium-ion cells to be used in
a variety of battery systems. Specific requirements for the safety of cells differ depending on
the system designs of battery packs or vehicles, and should be evaluated by the users. Final
pass-fail criteria of cells are to be based on the agreement between the cell manufacturers and
the customers.
SECONDARY LITHIUM-ION CELLS FOR THE PROPULSION
OF ELECTRIC ROAD VEHICLES –
Part 3: Safety requirements
1 Scope
This part of IEC 62660 specifies test procedures and acceptance criteria for safety performance
of secondary lithium-ion cells and cell blocks used for propulsion of electric vehicles (EV)
including battery electric vehicles (BEV) and hybrid electric vehicles (HEV).
NOTE 1 Cell blocks can be used as an alternative to cells according to the agreement between the manufacturer
and the customer.
NOTE 2 Concerning the cell for plug-in hybrid electric vehicle (PHEV), the manufacturer can select either the test
condition of the BEV application or the HEV application.
This document determines the basic safety performance of cells used in a battery pack and
system under intended use and reasonably foreseeable misuse or incident, during the normal
operation of the EV. The safety requirements of the cell in this document are based on the
premise that the cells are properly used in a battery pack and system within the limits for voltage,
current and temperature as specified by the cell manufacturer (cell operating region).
The evaluation of the safety of cells during transport and storage is not covered by this
document.
NOTE 1 The safety performance requirements for lithium-ion battery packs and systems are defined in ISO 12405-
3 ISO 6469‑1. The specifications and safety requirements for lithium-ion battery packs and systems of electrically
propelled mopeds and motorcycles are defined in ISO 18243. IEC 62619 covers the safety requirements for the
lithium-ion cells and batteries for industrial applications, including, for example, forklift trucks, golf carts, and
automated guided vehicles.
NOTE 4 Information on the cell operating region is provided in Annex A.
NOTE 2 Lithium cells, modules, battery packs, and battery systems are regulated by International Air Transport
Association (IATA) and International Maritime Organization (IMO) for air and sea transport, and, regionally, by other
authorities, mainly for land transport. Refer to IEC 62281 for additional information.
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 – Part 482: Primary and secondary
cells and batteries
IEC 61434, Secondary cells and batteries containing alkaline or other non-acid electrolytes –
Guide to the designation of current in alkaline secondary cell and battery standards
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
___________
Second edition under preparation. Stage at the time of publication: IEC FDIS 62619:20152021.
– 8 – IEC 62660-3:2022 RLV © IEC 2022
IEC 62660-2:20102018, Secondary lithium-ion cells for the propulsion of electric road vehicles
– Part 2: Reliability and abuse testing
ISO/TR 8713, Electrically propelled road vehicles – Vocabulary
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 60050-482
ISO/TR 8713 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
BEV
battery electric vehicle
electric vehicle with only a traction battery as power source for vehicle propulsion
3.2
cell block
group of cells connected together in parallel configuration with or without protective devices
(e.g. fuse or positive temperature coefficient resistor (PTC)) and not yet fitted with its final
housing, terminal arrangement and or electronic control device
3.3
cylindrical cell
cell with a cylindrical shape in which the overall height is equal to or greater than the diameter
[SOURCE: IEC 60050-482:2004, 482-02-39]
3.4
explosion
failure that occurs when a cell container, if any, opens violently and major components its solid
contents are forcibly expelled
3.5
fire
emission of flames from a cell or cell block for more than 1 s
Note 1 to entry: Sparks and arcing are not considered as flames.
3.6
HEV
hybrid electric vehicle
vehicle with both a rechargeable energy storage system and a fuelled power source for
propulsion
3.7
internal short-circuit
unintentional electrical connection between the negative and positive electrodes inside a cell
3.8
leakage
visible escape of liquid electrolyte from a part, except for a vent, such as casing the case,
sealing part, and/or terminals of the cell
3.9
nominal voltage
suitable approximate value of the voltage used to designate or identify a cell
[SOURCE: IEC 60050-482:2004, 482-03-31, modified – Deletion of "a battery or an
electrochemical system" at the end of the definition.]
3.10
pouch cell
cell having the shape of a parallelepiped whose faces are rectangular and with a prismatic
flexible laminate film case
3.11
prismatic cell
cell having the shape of a parallelepiped whose faces are rectangular and with a prismatic hard
case
[SOURCE: IEC 60050-482:2004, 482-02-38, modified − The word "cell" has been added to the
term, "qualifies a cell or a battery" has been replaced with "cell" in the definition, and "and with
a prismatic hard case housing" has been added.]
3.12
rated capacity
C
n
quantity of electricity C Ah (ampere-hours) for BEV and C Ah for HEV declared by the
3 1
manufacturer
capacity value of a cell in ampere hours (Ah) determined under specified conditions and
declared by the cell manufacturer
Note 1 to entry: The subscript n in C is the time base in hours (h). In this document, n = 3 for BEV application and
n
n = 1 for HEV application unless otherwise specified.
Note 2 to entry: Term and definition based on IEC 60050-482:2004, 482-03-15.
3.13
reference test current
I
t
reference test current in amperes (A) which is expressed as
I (A) = C (Ah)/n (h)
t n
where
C is the rated capacity of the cell;
n
n in C is the time base (h).
n
I = C / 1
t n
Note 1 to entry: 1 has a dimension of time in hours (h).
Note 2 to entry: See IEC 61434:1996, Clause 2.
– 10 – IEC 62660-3:2022 RLV © IEC 2022
3.11
room temperature
temperature of 25 °C ± 2 K
3.14
rupture
mechanical failure of a container case of a cell induced by an internal or external cause,
resulting in exposure or spillage but not ejection of materials
3.15
secondary lithium-ion cell
cell
secondary single cell whose electrical energy is derived from the insertion/extraction reactions
of lithium-ions between the anode negative electrode and the cathode positive electrode
Note 1 to entry: A secondary cell is a basic manufactured unit providing a source of electrical energy by direct
conversion of chemical energy. The cell consists of electrodes, electrolyte, container, terminals and, if any,
separators. The electrode can be monopolar or bipolar; the current collector of the former has active material of
single polarity and the latter has positive and negative electrode active materials. The electrolyte includes an ionic
conductive liquid or solid, or a mixture of them. The cell is designed to be charged electrically.
Note 2 to entry: In this standard, "cell" means the "secondary lithium-ion cell" to be used for the propulsion of
electric road vehicles. Where the term "cell" is used alone in this document, it refers to a secondary lithium-ion cell.
3.16
SOC
state of charge
available capacity in a battery expressed as a percentage of rated capacity
quantity of electricity stored in a cell expressed as a percentage of rated capacity
3.17
upper limit charging voltage
highest charging voltage in the cell operating region, which is specified by the cell manufacturer
Note 1 to entry: Information on the cell operating region is provided in Annex A.
[SOURCE: IEC 62133-2:2017, 3.19, modified − Note to entry added.]
3.18
venting
release of excessive internal pressure from a cell in a manner intended by design to preclude
rupture or explosion
4 Test conditions
4.1 General
Unless otherwise stated in this document, cells shall be tested at room temperature. For the
purposes of this document, room temperature is 25 °C ± 2 K.
The details of the instrumentation used shall be provided in any report of results.
The cell can be tested under restraint to avoid swelling if acceptable according to the purpose
of test. The restraint should refer to the battery design.
Cell blocks can be tested as an alternative to cells in accordance with the agreement between
the cell manufacturer and the customer.
Concerning the cell for plug-in hybrid electric vehicles (PHEV), the cell manufacturer can select
either the test condition of BEV application or of HEV application.
NOTE Test and measurement can be conducted in a fixture as recommended by the cell manufacturer.
4.2 Measuring instruments
4.2.1 Range of measuring devices
The instruments used shall enable the values of voltage and current to be measured. The range
of these instruments and measuring methods shall be chosen so as to ensure the accuracy
specified for each test.
For analogue instruments, this implies that the readings shall be taken in the last third of the
graduated scale.
Any other measuring instruments may be used provided they give an equivalent accuracy.
4.2.2 Voltage measurement
The resistance of the voltmeters used shall be at least 1 MΩ/V.
4.2.3 Current measurement
The entire assembly of ammeter, shunt and leads shall be of an accuracy class of 0,5 or better.
4.2.4 Temperature measurements
The cell temperature shall be measured by use of a surface temperature measuring device
capable of an equivalent scale definition and accuracy of calibration as specified in 4.2.1. The
temperature should be measured at a location which most closely reflects the cell or cell block
temperature. The temperature may be measured at additional appropriate locations, if
necessary.
The examples for temperature measurement are shown in Figure 1. The instructions for
temperature measurement specified by the cell manufacturer shall be followed.
– 12 – IEC 62660-3:2022 RLV © IEC 2022
Prismatic or flat cell
Cylindrical cell
Temperature measuring device
Cell Cell
Thermal insulating material
IECI
Figure 1 – Example of temperature measurement of cell
4.2.5 Other measurements
Other values including capacity and power may be measured by use of a measuring device,
provided it complies with 4.3.
4.3 Tolerance
The overall accuracy of controlled or measured values, relative to the specified or actual values,
shall be within the following tolerances:
a) ±0,1 % for voltage;
b) ±1 % for current;
c) ±2 K for temperature;
d) ±0,1 % for time;
e) ±0,1 % for mass;
f) ±0,1 % for dimensions.
These tolerances comprise the combined accuracy of the measuring instruments, the
measurement technique used, and all other sources of error in the test procedure.
Cell
4.4 Test temperature Thermal stabilization
If not otherwise defined, before each test the cell has to be stabilized at the test For the
stabilization of cell temperature, the cell shall be soaked to a specified ambient temperature for
a minimum of 12 h. This period can may be reduced if thermal equilibrium stabilization is
reached. Thermal equilibrium stabilization is considered to be reached if after one interval of 1
h, the change of cell temperature is lower than 1 K.
Unless otherwise stated in this standard, cells shall be tested at room temperature.
5 Electrical measurement
5.1 General charge conditions
Unless otherwise stated in this document, prior to the electrical measurement test, the cell shall
be charged as follows.
Prior to charging, the cell shall be discharged at room temperature at a constant current of
1/3 I (A) for BEV application and 1 I (A) for HEV application down to an end-of-discharge
t t
voltage specified by the cell manufacturer. Then, the cell shall be charged at room temperature
according to the charging method declared by the cell manufacturer.
5.2 Capacity
Before the SOC adjustment in 5.3, the capacity of the test cell shall be confirmed to be the
rated value in accordance with the following phases.
1) Phase 1 – The cell shall be charged in accordance with 5.1. After recharge, the cell
temperature shall be stabilized in accordance with 4.4.
2) Phase 2 – The cell shall be discharged at room temperature at a constant current of
1/3 I (A) for BEV application and at 1 I (A) for HEV application to the end-of-discharge
t t
voltage that is provided specified by the cell manufacturer.
3) Phase 3 – Measure the discharge endurance duration until the specified end-of-discharge
voltage is reached, and calculate the capacity of the cell expressed in Ah up to three
significant figures.
5.3 SOC adjustment
The test cells shall be charged as specified in the following list. The SOC adjustment is the
procedure to be followed for preparing cells to the various SOCs for the tests in this document.
1) Phase 1 – The cell shall be charged in accordance with 5.1.
2) Phase 2 – The cell shall be left at rest at room temperature in accordance with 4.4.
3) Phase 3 – The cell shall be discharged at a constant current of 1/3 I (A) for BEV application
t
and of 1 I (A) for HEV application for (100 – n)/100 × 3 h for BEV application and
t
(100 – n)/100 × 1 h for HEV application, where n is SOC (%) to be adjusted for each test.
6 Safety tests
6.1 General
For all the tests specified in this Clause 6, the test installation shall be reported, including the
method used for fixing and wiring of the cell. If necessary, to prevent deformation, the cell may
be maintained during the test in a manner that complies with the test purpose.
The tests shall be performed on cells that are not more than six months old. The number of
cells under each test can be determined according to the agreement between the cell
– 14 – IEC 62660-3:2022 RLV © IEC 2022
manufacturer and the customer. A cell block may be used for testing in place of a single cell in
accordance with the agreement between the cell manufacturer and the customer.
The number and type of test samples (cell or cell block) shall be provided in a test report.
Each test shall end with the one-hour observation period, unless otherwise specified in this
document.
Warning: THE TESTS USE PROCEDURES WHICH MAY RESULT IN HARM IF ADEQUATE
PRECAUTIONS ARE NOT TAKEN. TESTS SHOULD ONLY BE PERFORMED BY
QUALIFIED AND EXPERIENCED TECHNICIANS USING ADEQUATE PROTECTION. TO
PREVENT BURNS, CAUTION SHOULD BE TAKEN FOR THOSE CELLS WHOSE CASINGS
CASES MAY EXCEED 75 °C AS A RESULT OF TESTING.
6.2 Mechanical tests
6.2.1 Vibration
6.2.1.1 Purpose
This test is performed to simulate vibration to a cell that may occur during the normal operation
of the vehicle, and to verify the safety performance of the cell under such conditions.
6.2.1.2 Test
The test shall be performed in accordance with 6.1.1.1 of IEC 62660-2:2010.
6.2.1.3 Acceptance criteria
During the test, the cell shall exhibit no evidence of leakage, venting, rupture, fire or explosion.
6.2.1 Mechanical shock
6.2.1.1 Purpose
This test is performed to simulate mechanical shocks to a cell that may occur during the normal
operation of the vehicle, and to verify the safety performance of the cell under such conditions.
6.2.1.2 Test
The test shall be performed in accordance with 6.2.2.2 of IEC 62660-2:20102018.
6.2.1.3 Acceptance criteria
During the test, the cell shall exhibit no evidence of leakage, venting, rupture, fire or explosion.
6.2.2 Crush
6.2.2.1 Purpose
This test is performed to simulate external load forces that may cause deformation of a cell,
and to verify the safety performance of the cell under such conditions.
6.2.2.2 Test
The test shall be performed as follows:
a) adjust the SOC of cell to 100 % for BEV application and to 80 % for HEV application in
accordance with 5.3;
b) the cell shall be placed on an insulated rigid flat supporting surface, and a force shall be
applied to it with a crushing tool made of a solid material in the shape of a round or
semicircular bar, or in the shape of a sphere or hemisphere with a 150 mm diameter. It is
recommended to use the round bar to crush a cylindrical cell, and the sphere for a prismatic
cell, including a flat or pouch cell. The force for the crushing shall be applied in a direction
nearly perpendicular to a larger side of the layered face of the positive and negative
electrodes inside the cell. The force shall be applied to the approximate centre of the cell
as shown in Figure 2. The crush speed shall be less than or equal to 6 mm/min;
NOTE The round bar can be used to crush a cylindrical cell, and the sphere can be used to crush a prismatic
cell or pouch cell.
c) the force shall be released when an abrupt voltage drop of one-third of the original cell
voltage occurs, or a deformation of 15 % or more of the initial cell dimension occurs, or a
force of 1 000 times the weight of the cell is applied, whichever comes first. The cells shall
be under observation for 24 h or until the cell temperature declines by 80 % of the maximum
temperature rise, whichever occurs sooner.
a) Example for cylindrical cell b) Example for prismatic cell
Figure 2 – Example of crush test
6.2.2.3 Acceptance criteria
During the test, the cell shall exhibit no evidence of fire or explosion.
6.3 Thermal test
6.3.1 High temperature endurance
6.3.1.1 Purpose
This test is performed to simulate a high-temperature environment that the cell may experience
during the reasonably foreseeable misuse or incident of the vehicle, and to verify the safety
performance of the cell under such conditions.
6.3.1.2 Test
The test shall be performed as follows:
– 16 – IEC 62660-3:2022 RLV © IEC 2022
a) adjust the SOC of the cell to 100 % for BEV applications, and to 80 % for HEV applications
in accordance with 5.3;
b) the cell, stabilized at room temperature, shall be placed in a gravity or circulating air
convection oven. The oven temperature shall be raised at a rate of 5 K/min to 130 °C ± 2 K.
The cell shall remain at this temperature for 30 min. Then, after the heater is turned off, the
cell shall be observed for 1 h in the oven.
NOTE If necessary, to prevent deformation, the cell can be maintained during the test in a manner that does not
violate the test purpose.
6.3.1.3 Acceptance criteria
During the test, the cell shall exhibit no evidence of fire or explosion.
6.3.2 Temperature cycling
6.3.2.1 Purpose
This test is performed to simulate the anticipated exposure to low and high environmental
temperature variations which can result in expansion and contraction of cell components, and
to verify the safety performance of the cell under such conditions.
6.3.2.2 Test
The test shall be performed in accordance with 6.3.2.2 of IEC 62660-2:20102018.
6.3.2.3 Acceptance criteria
During the test, the cell shall exhibit no evidence of leakage, venting, rupture, fire or explosion.
6.4 Electrical tests
If necessary, to prevent deformation, the cell can be maintained during the test in a manner
that does not violate the test purpose.
6.4.1 External short-circuit
6.4.1.1 Purpose
This test is performed to simulate an external short-circuit of a cell, and to verify the safety
performance of the cell under such conditions.
6.4.1.2 Test
The test shall be performed in accordance with 6.4.1.2 of IEC 62660-2:20102018.
6.4.1.3 Acceptance criteria
During the test, the cell shall exhibit no evidence of fire or explosion.
6.4.2 Overcharge
6.4.2.1 Purpose
This test is performed to simulate an overcharge of a cell, and to verify the safety performance
of the cell under such conditions.
6.4.2.2 Test
The test shall be performed as follows:
a) adjust the SOC of the cell to 100 % in accordance with 5.3;
b) continue charging the cell beyond the 100 % SOC with a charging current 1 I or 1/3 I for
t t
BEV application and 5 I or 1 I for HEV application at room temperature using a power
t t
supply sufficient to provide the constant charging current. The overcharge test shall be
discontinued when the voltage of the cell reaches or exceeds 120 % of the maximum voltage
specified by the cell manufacturer, or the quantity of electricity applied to the cell reaches
or exceeds the equivalent of 130 % SOC, whichever comes first.
c) the test conditions may be according to the agreement between the cell manufacturer and
the customer.
6.4.2.3 Acceptance criteria
During the test, the cell shall exhibit no evidence of fire or explosion.
6.4.3 Forced discharge
6.4.3.1 Purpose
This test is performed to simulate an overdischarge of a cell, and to verify the safety
performance of the cell under such conditions.
6.4.3.2 Test
The test shall be performed as follows:
a) adjust the SOC of the cell to 0 % in accordance with 5.3;
b) continue discharging the cell beyond the 0 % SOC with a 1 I discharging current at room
t
temperature. The forced discharge test shall be discontinued when the absolute value of
the voltage of the cell reaches 25 % or less of the nominal voltage specified by the cell
manufacturer, or the cell is discharged for 30 min, whichever occurs sooner.
6.4.3.3 Acceptance criteria
During the test, the cell shall exhibit no evidence of leakage, venting, rupture, fire or explosion.
6.4.4 Internal short-circuit test
6.4.4.1 Purpose
This test is performed to simulate an internal short-circuit of a cell which is caused by its
contamination with a conductive particle, etc., and to verify the safety performance of the cell
under such conditions.
NOTE Annex B provides the informative explanation on the internal short-circuit test.
6.4.4.2 Test
6.4.4.2.1 Forced internal short-circuit test
The test shall be performed on the cell in accordance with 7.3.2 b) of IEC 62619:— , except as
follows.
When the nickel particle is placed between the positive active material coated area and the
negative active material coated area, the internal short-circuit of single layer shall be confirmed.
The prescribed specified test conditions, such as the pressing force and the shape of jig, may
___________
Second edition under preparation. Stage at the time of publication: IEC FDIS 62619:20152021.
– 18 – IEC 62660-3:2022 RLV © IEC 2022
be modified, if necessary in order to simulate the internal short-circuit of single layer. The case
and electrodes of the cell shall not be crushed. The Any modification shall be recorded reported.
The nickel particle may be inserted through an incision in the cell case, without extracting the
electrode core (winding, stacking or folding type) from the cell case. In such a case, the position
of the nickel particle may not be the centre of cell, to the extent that the test result is not
influenced.
NOTE 1 The internal short-circuit of a single layer can be confirmed is usually indicated by a voltage drop of a few
mV.
NOTE 2 In cases where the aluminium foil of positive electrode is exposed at the outer turn, and
that it faces the negative active material, the nickel particle is placed at the centre of the cell
between the negative active material coated area and the positive aluminium foil which is at the
end of the positive active material coated area in the winding direction. The other area where
the positive aluminium foil faces the negative active material, if any, can may be checked by
the design review, failure mode and effects analysis (FMEA), etc. according to the agreement
between the cell supplier manufacturer and the customer.
6.4.4.2.2 Alternative internal short-circuit test
The other test methods to simulate the internal short circuit of cell caused by the contamination
of conductive particles may be selected if the following criteria are satisfied and agreed between
the customer and the supplier.
a) The case deformation shall not affect the short circuit event of cell thermally or electrically.
The energy shall not be dispersed by any short circuit other than the interelectrode short
circuit.
b) One layer internal short circuit between the positive electrode and the negative electrode
shall be simulated (target).
c) Approximately the same short circ
...
IEC 62660-3 ®
Edition 2.0 2022-03
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Secondary lithium-ion cells for the propulsion of electric road vehicles –
Part 3: Safety requirements
Éléments d’accumulateurs lithium-ion pour la propulsion des véhicules routiers
électriques –
Partie 3: Exigences de sécurité
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IEC 62660-3 ®
Edition 2.0 2022-03
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Secondary lithium-ion cells for the propulsion of electric road vehicles –
Part 3: Safety requirements
Éléments d’accumulateurs lithium-ion pour la propulsion des véhicules routiers
électriques –
Partie 3: Exigences de sécurité
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.220.20; 43.120 ISBN 978-2-8322-1083-3
– 2 – IEC 62660-3:2022 © IEC 2022
CONTENTS
FOREWORD . 4
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
4 Test conditions . 9
4.1 General . 9
4.2 Measuring instruments . 9
4.2.1 Range of measuring devices . 9
4.2.2 Voltage measurement . 9
4.2.3 Current measurement . 9
4.2.4 Temperature measurements . 9
4.2.5 Other measurements . 10
4.3 Tolerance . 10
4.4 Thermal stabilization . 10
5 Electrical measurement . 10
5.1 General charge conditions . 10
5.2 Capacity . 11
5.3 SOC adjustment . 11
6 Safety tests . 11
6.1 General . 11
6.2 Mechanical tests . 12
6.2.1 Mechanical shock . 12
6.2.2 Crush . 12
6.3 Thermal test . 13
6.3.1 High temperature endurance. 13
6.3.2 Temperature cycling . 13
6.4 Electrical tests . 14
6.4.1 External short-circuit . 14
6.4.2 Overcharge . 14
6.4.3 Forced discharge . 14
6.4.4 Internal short-circuit test . 15
Annex A (informative) Operating region of cells for safe use . 17
A.1 General . 17
A.2 Charging conditions for safe use . 17
A.2.1 General . 17
A.2.2 Consideration on charging voltage . 17
A.2.3 Consideration on temperature . 18
A.3 Example of operating region . 19
Annex B (informative) Explanation for the internal short-circuit test . 20
B.1 General concept . 20
B.2 Internal short-circuit caused by the particle contamination . 20
Annex C (normative) Alternative internal short-circuit test (6.4.4.2.2) . 22
C.1 General . 22
C.2 Test preparation and test set-up . 22
C.2.1 Preparation of cell before the test . 22
C.2.2 Test setup . 24
C.2.3 Preliminary test . 25
C.3 Test procedure . 26
C.4 Acceptance criteria . 26
Bibliography . 27
Figure 1 – Example of temperature measurement of cell . 10
Figure 2 – Example of crush test . 13
Figure A.1 – An example of operating region for charging of typical lithium-ion cells . 19
Figure A.2 – An example of operating region for discharging of typical lithium-ion cells . 19
Figure C.1 – Example of case thinning . 22
Figure C.2 – Example of thinning tool . 23
Figure C.3 – Example of removing hard case . 23
Figure C.4 – Example of hard case removal method during cell manufacturing . 23
Figure C.5 – Example of fixation of cell . 24
Figure C.6 – Test setup image for voltage measurement . 24
Figure C.7 – Example of abrupt voltage drop . 25
Table B.1 – Examples of the internal short-circuit of cell . 20
– 4 – IEC 62660-3:2022 © IEC 2022
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
SECONDARY LITHIUM-ION CELLS FOR THE PROPULSION
OF ELECTRIC ROAD VEHICLES –
Part 3: Safety requirements
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 62660-3 has been prepared by IEC technical committee 21: Secondary cells and batteries.
It is an International Standard.
This second edition cancels and replaces the first edition published in 2016. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) The new method for the internal short-circuit test has been added in 6.4.4.2.2 and Annex C,
as an alternative option to the test in 6.4.4.2.1.
b) The vibration test has been deleted.
c) The test conditions of overcharge (6.4.2.2) have been partially revised.
The text of this International Standard is based on the following documents:
Draft Report on voting
21/1133/FDIS 21/1137/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.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/standardsdev/publications.
A list of all parts in the IEC 62660 series, published under the general title Secondary lithium-ion
cells for the propulsion of electric road vehicles, 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.
– 6 – IEC 62660-3:2022 © IEC 2022
SECONDARY LITHIUM-ION CELLS FOR THE PROPULSION
OF ELECTRIC ROAD VEHICLES –
Part 3: Safety requirements
1 Scope
This part of IEC 62660 specifies test procedures and acceptance criteria for safety performance
of secondary lithium-ion cells and cell blocks used for propulsion of electric vehicles (EV)
including battery electric vehicles (BEV) and hybrid electric vehicles (HEV).
This document determines the basic safety performance of cells used in a battery pack and
system under intended use and reasonably foreseeable misuse or incident, during the normal
operation of the EV. The safety requirements of the cell in this document are based on the
premise that the cells are properly used in a battery pack and system within the limits for voltage,
current and temperature as specified by the cell manufacturer (cell operating region).
The evaluation of the safety of cells during transport and storage is not covered by this
document.
NOTE 1 The safety performance requirements for lithium-ion battery packs and systems are defined in ISO 6469‑1.
The specifications and safety requirements for lithium-ion battery packs and systems of electrically propelled mopeds
and motorcycles are defined in ISO 18243. IEC 62619 covers the safety requirements for the lithium-ion cells and
batteries for industrial applications, including, for example, forklift trucks, golf carts, and automated guided vehicles.
NOTE 2 Lithium cells, modules, battery packs, and battery systems are regulated by International Air Transport
Association (IATA) and International Maritime Organization (IMO) for air and sea transport, and, regionally, by other
authorities, mainly for land transport. Refer to IEC 62281 for additional information.
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 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 62660-2:2018, Secondary lithium-ion cells for the propulsion of electric road vehicles –
Part 2: Reliability and abuse testing
ISO/TR 8713, Electrically propelled road vehicles – Vocabulary
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO/TR 8713 and the
following apply.
___________
Second edition under preparation. Stage at the time of publication: IEC FDIS 62619:2021.
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
BEV
battery electric vehicle
electric vehicle with only a traction battery as power source for vehicle propulsion
3.2
cell block
group of cells connected together in parallel configuration with or without protective devices
(e.g. fuse or positive temperature coefficient resistor (PTC)) and not yet fitted with its final
housing, terminal arrangement or electronic control device
3.3
cylindrical cell
cell with a cylindrical shape in which the overall height is equal to or greater than the diameter
[SOURCE: IEC 60050-482:2004, 482-02-39]
3.4
explosion
failure that occurs when a cell container opens violently and its solid contents are forcibly
expelled
3.5
fire
emission of flames from a cell or cell block for more than 1 s
Note 1 to entry: Sparks and arcing are not considered as flames.
3.6
HEV
hybrid electric vehicle
vehicle with both a rechargeable energy storage system and a fuelled power source for
propulsion
3.7
internal short-circuit
unintentional electrical connection between the negative and positive electrodes inside a cell
3.8
leakage
visible escape of liquid electrolyte from a part, except for a vent, such as the case, sealing part,
and/or terminals of the cell
3.9
nominal voltage
suitable approximate value of the voltage used to designate or identify a cell
[SOURCE: IEC 60050-482:2004, 482-03-31, modified – Deletion of "a battery or an
electrochemical system" at the end of the definition.]
– 8 – IEC 62660-3:2022 © IEC 2022
3.10
pouch cell
cell having the shape of a parallelepiped whose faces are rectangular and with a prismatic
flexible laminate film case
3.11
prismatic cell
cell having the shape of a parallelepiped whose faces are rectangular and with a prismatic hard
case
[SOURCE: IEC 60050-482:2004, 482-02-38, modified − The word "cell" has been added to the
term, "qualifies a cell or a battery" has been replaced with "cell" in the definition, and "and with
a prismatic hard case housing" has been added.]
3.12
rated capacity
C
n
capacity value of a cell in ampere hours (Ah) determined under specified conditions and
declared by the cell manufacturer
Note 1 to entry: The subscript n in C is the time base in hours (h). In this document, n = 3 for BEV application and
n
n = 1 for HEV application unless otherwise specified.
Note 2 to entry: Term and definition based on IEC 60050-482:2004, 482-03-15.
3.13
reference test current
I
t
reference test current in amperes (A) which is expressed as
I = C / 1
t n
Note 1 to entry: 1 has a dimension of time in hours (h).
Note 2 to entry: See IEC 61434:1996, Clause 2.
3.14
rupture
mechanical failure of a container case of a cell induced by an internal or external cause,
resulting in exposure or spillage but not ejection of materials
3.15
secondary lithium-ion cell
secondary single cell whose electrical energy is derived from the insertion/extraction reactions
of lithium-ions between the negative electrode and the positive electrode
Note 1 to entry: A secondary cell is a manufactured unit providing a source of electrical energy by direct conversion
of chemical energy. The cell consists of electrodes, electrolyte, container, terminals and, if any, separators. The
electrode can be monopolar or bipolar; the current collector of the former has active material of single polarity and
the latter has positive and negative electrode active materials. The electrolyte includes an ionic conductive liquid or
solid, or a mixture of them. The cell is designed to be charged electrically.
Note 2 to entry: Where the term "cell" is used alone in this document, it refers to a secondary lithium-ion cell.
3.16
SOC
state of charge
quantity of electricity stored in a cell expressed as a percentage of rated capacity
3.17
upper limit charging voltage
highest charging voltage in the cell operating region, which is specified by the cell manufacturer
Note 1 to entry: Information on the cell operating region is provided in Annex A.
[SOURCE: IEC 62133-2:2017, 3.19, modified − Note to entry added.]
3.18
venting
release of excessive internal pressure from a cell in a manner intended by design to preclude
rupture or explosion
4 Test conditions
4.1 General
Unless otherwise stated in this document, cells shall be tested at room temperature. For the
purposes of this document, room temperature is 25 °C ± 2 K.
The details of the instrumentation used shall be provided in any report of results.
Cell blocks can be tested as an alternative to cells in accordance with the agreement between
the cell manufacturer and the customer.
Concerning the cell for plug-in hybrid electric vehicles (PHEV), the cell manufacturer can select
either the test condition of BEV application or of HEV application.
NOTE Test and measurement can be conducted in a fixture as recommended by the cell manufacturer.
4.2 Measuring instruments
4.2.1 Range of measuring devices
The instruments used shall enable the values of voltage and current to be measured. The range
of these instruments and measuring methods shall be chosen so as to ensure the accuracy
specified for each test.
For analogue instruments, this implies that the readings shall be taken in the last third of the
graduated scale.
Any other measuring instruments may be used provided they give an equivalent accuracy.
4.2.2 Voltage measurement
The resistance of the voltmeters used shall be at least 1 MΩ/V.
4.2.3 Current measurement
The entire assembly of ammeter, shunt and leads shall be of an accuracy class of 0,5 or better.
4.2.4 Temperature measurements
The cell temperature shall be measured by use of a surface temperature measuring device
capable of an equivalent scale definition and accuracy of calibration as specified in 4.2.1. The
temperature should be measured at a location which most closely reflects the cell or cell block
temperature. The temperature may be measured at additional appropriate locations, if
necessary.
– 10 – IEC 62660-3:2022 © IEC 2022
The examples for temperature measurement are shown in Figure 1. The instructions for
temperature measurement specified by the cell manufacturer shall be followed.
Figure 1 – Example of temperature measurement of cell
4.2.5 Other measurements
Other values may be measured by use of a measuring device, provided it complies with 4.3.
4.3 Tolerance
The overall accuracy of controlled or measured values, relative to the specified or actual values,
shall be within the following tolerances:
a) ±0,1 % for voltage;
b) ±1 % for current;
c) ±2 K for temperature;
d) ±0,1 % for time;
e) ±0,1 % for mass;
f) ±0,1 % for dimensions.
These tolerances comprise the combined accuracy of the measuring instruments, the
measurement technique used, and all other sources of error in the test procedure.
4.4 Thermal stabilization
For the stabilization of cell temperature, the cell shall be soaked to a specified ambient
temperature for a minimum of 12 h. This period may be reduced if thermal stabilization is
reached. Thermal stabilization is considered to be reached if after one interval of 1 h, the
change of cell temperature is lower than 1 K.
5 Electrical measurement
5.1 General charge conditions
Unless otherwise stated in this document, prior to the electrical measurement, the cell shall be
charged as follows.
Prior to charging, the cell shall be discharged at room temperature at a constant current of
1/3 I (A) for BEV application and 1 I (A) for HEV application down to an end-of-discharge
t t
voltage specified by the cell manufacturer. Then, the cell shall be charged at room temperature
according to the charging method declared by the cell manufacturer.
5.2 Capacity
Before the SOC adjustment in 5.3, the capacity of the test cell shall be confirmed to be the
rated value in accordance with the following phases.
1) Phase 1 – The cell shall be charged in accordance with 5.1. After charge, the cell
temperature shall be stabilized in accordance with 4.4.
2) Phase 2 – The cell shall be discharged at room temperature at a constant current of
1/3 I (A) for BEV application and at 1 I (A) for HEV application to the end-of-discharge
t t
voltage that is specified by the cell manufacturer.
3) Phase 3 – Measure the discharge duration until the specified end-of-discharge voltage is
reached, and calculate the capacity of the cell expressed in Ah up to three significant
figures.
5.3 SOC adjustment
The test cells shall be charged as specified in the following list. The SOC adjustment is the
procedure to be followed for preparing cells to the various SOCs for the tests in this document.
1) Phase 1 – The cell shall be charged in accordance with 5.1.
2) Phase 2 – The cell shall be left at rest at room temperature in accordance with 4.4.
3) Phase 3 – The cell shall be discharged at a constant current of 1/3 I (A) for BEV application
t
and of 1 I (A) for HEV application for (100 – n)/100 × 3 h for BEV application and
t
(100 – n)/100 × 1 h for HEV application, where n is SOC (%) to be adjusted for each test.
6 Safety tests
6.1 General
For all the tests specified in this Clause 6, the test installation shall be reported, including the
method used for fixing and wiring of the cell. If necessary, to prevent deformation, the cell may
be maintained during the test in a manner that complies with the test purpose.
The tests shall be performed on cells that are not more than six months old. The number of
cells under each test can be determined according to the agreement between the cell
manufacturer and the customer. A cell block may be used for testing in place of a single cell in
accordance with the agreement between the cell manufacturer and the customer.
The number and type of test samples (cell or cell block) shall be provided in a test report.
Each test shall end with the one-hour observation period, unless otherwise specified in this
document.
Warning: THE TESTS USE PROCEDURES WHICH MAY RESULT IN HARM IF ADEQUATE
PRECAUTIONS ARE NOT TAKEN. TESTS SHOULD ONLY BE PERFORMED BY
QUALIFIED AND EXPERIENCED TECHNICIANS USING ADEQUATE PROTECTION. TO
PREVENT BURNS, CAUTION SHOULD BE TAKEN FOR THOSE CELLS WHOSE CASES
MAY EXCEED 75 °C AS A RESULT OF TESTING.
– 12 – IEC 62660-3:2022 © IEC 2022
6.2 Mechanical tests
6.2.1 Mechanical shock
6.2.1.1 Purpose
This test is performed to simulate mechanical shocks to a cell that may occur during the normal
operation of the vehicle, and to verify the safety performance of the cell under such conditions.
6.2.1.2 Test
The test shall be performed in accordance with 6.2.2.2 of IEC 62660-2:2018.
6.2.1.3 Acceptance criteria
During the test, the cell shall exhibit no evidence of leakage, venting, rupture, fire or explosion.
6.2.2 Crush
6.2.2.1 Purpose
This test is performed to simulate external load forces that may cause deformation of a cell,
and to verify the safety performance of the cell under such conditions.
6.2.2.2 Test
The test shall be performed as follows:
a) adjust the SOC of cell to 100 % for BEV application and to 80 % for HEV application in
accordance with 5.3;
b) the cell shall be placed on an insulated rigid flat supporting surface, and a force shall be
applied to it with a crushing tool made of a solid material in the shape of a round or
semicircular bar, or in the shape of a sphere or hemisphere with a 150 mm diameter. The
force for the crushing shall be applied in a direction nearly perpendicular to a larger side of
the layered face of the positive and negative electrodes inside the cell. The force shall be
applied to the approximate centre of the cell as shown in Figure 2. The crush speed shall
be less than or equal to 6 mm/min;
NOTE The round bar can be used to crush a cylindrical cell, and the sphere can be used to crush a prismatic
cell or pouch cell.
c) the force shall be released when an abrupt voltage drop of one-third of the original cell
voltage occurs, or a deformation of 15 % or more of the initial cell dimension occurs, or a
force of 1 000 times the weight of the cell is applied, whichever comes first. The cells shall
be under observation for 24 h or until the cell temperature declines by 80 % of the maximum
temperature rise, whichever occurs sooner.
a) Example for cylindrical cell b) Example for prismatic cell
Figure 2 – Example of crush test
6.2.2.3 Acceptance criteria
During the test, the cell shall exhibit no evidence of fire or explosion.
6.3 Thermal test
6.3.1 High temperature endurance
6.3.1.1 Purpose
This test is performed to simulate a high-temperature environment that the cell may experience
during the reasonably foreseeable misuse or incident of the vehicle, and to verify the safety
performance of the cell under such conditions.
6.3.1.2 Test
The test shall be performed as follows:
a) adjust the SOC of the cell to 100 % for BEV applications, and to 80 % for HEV applications
in accordance with 5.3;
b) the cell, stabilized at room temperature, shall be placed in a gravity or circulating air
convection oven. The oven temperature shall be raised at a rate of 5 K/min to 130 °C ± 2 K.
The cell shall remain at this temperature for 30 min. Then, after the heater is turned off, the
cell shall be observed for 1 h in the oven.
6.3.1.3 Acceptance criteria
During the test, the cell shall exhibit no evidence of fire or explosion.
6.3.2 Temperature cycling
6.3.2.1 Purpose
This test is performed to simulate the anticipated exposure to low and high environmental
temperature variations which can result in expansion and contraction of cell components, and
to verify the safety performance of the cell under such conditions.
– 14 – IEC 62660-3:2022 © IEC 2022
6.3.2.2 Test
The test shall be performed in accordance with 6.3.2.2 of IEC 62660-2:2018.
6.3.2.3 Acceptance criteria
During the test, the cell shall exhibit no evidence of leakage, venting, rupture, fire or explosion.
6.4 Electrical tests
6.4.1 External short-circuit
6.4.1.1 Purpose
This test is performed to simulate an external short-circuit of a cell, and to verify the safety
performance of the cell under such conditions.
6.4.1.2 Test
The test shall be performed in accordance with 6.4.1.2 of IEC 62660-2:2018.
6.4.1.3 Acceptance criteria
During the test, the cell shall exhibit no evidence of fire or explosion.
6.4.2 Overcharge
6.4.2.1 Purpose
This test is performed to simulate an overcharge of a cell, and to verify the safety performance
of the cell under such conditions.
6.4.2.2 Test
The test shall be performed as follows:
a) adjust the SOC of the cell to 100 % in accordance with 5.3;
b) continue charging the cell beyond the 100 % SOC with a charging current 1 I or 1/3 I for
t t
BEV application and 5 I or 1 I for HEV application at room temperature using a power
t t
supply sufficient to provide the constant charging current. The overcharge test shall be
discontinued when the voltage of the cell reaches or exceeds 120 % of the maximum voltage
specified by the cell manufacturer, or the quantity of electricity applied to the cell reaches
or exceeds the equivalent of 130 % SOC, whichever comes first.
c) the test conditions may be according to the agreement between the cell manufacturer and
the customer.
6.4.2.3 Acceptance criteria
During the test, the cell shall exhibit no evidence of fire or explosion.
6.4.3 Forced discharge
6.4.3.1 Purpose
This test is performed to simulate an overdischarge of a cell, and to verify the safety
performance of the cell under such conditions.
6.4.3.2 Test
The test shall be performed as follows:
a) adjust the SOC of the cell to 0 % in accordance with 5.3;
b) continue discharging the cell beyond the 0 % SOC with a 1 I discharging current at room
t
temperature. The forced discharge test shall be discontinued when the absolute value of
the voltage of the cell reaches 25 % or less of the nominal voltage specified by the cell
manufacturer, or the cell is discharged for 30 min, whichever occurs sooner.
6.4.3.3 Acceptance criteria
During the test, the cell shall exhibit no evidence of leakage, venting, rupture, fire or explosion.
6.4.4 Internal short-circuit test
6.4.4.1 Purpose
This test is performed to simulate an internal short-circuit of a cell which is caused by its
contamination with a conductive particle, etc., and to verify the safety performance of the cell
under such conditions.
NOTE Annex B provides the informative explanation on the internal short-circuit test.
6.4.4.2 Test
6.4.4.2.1 Forced internal short-circuit test
The test shall be performed on the cell in accordance with 7.3.2 b) of IEC 62619:— , except as
follows.
When the nickel particle is placed between the positive active material coated area and the
negative active material coated area, the internal short-circuit of single layer shall be confirmed.
The specified test conditions, such as the pressing force and the shape of jig, may be modified,
if necessary in order to simulate the internal short-circuit of single layer. The case and
electrodes of the cell shall not be crushed. Any modification shall be reported.
The nickel particle may be inserted through an incision in the cell case, without extracting the
electrode core (winding, stacking or folding type) from the cell case. In such a case, the position
of the nickel particle may not be the centre of cell, to the extent that the test result is not
influenced.
NOTE The internal short-circuit of a single layer is usually indicated by a voltage drop of a few mV.
In cases where the aluminium foil of positive electrode is exposed at the outer turn, and that it
faces the negative active material, the nickel particle is placed at the centre of the cell between
the negative active material coated area and the positive aluminium foil which is at the end of
the positive active material coated area in the winding direction. The other area where the
positive aluminium foil faces the negative active material, if any, may be checked by the design
review, failure mode and effects analysis (FMEA), etc. according to the agreement between the
cell manufacturer and the customer.
6.4.4.2.2 Alternative internal short-circuit test
If agreed between the cell manufacturer and the customer, the internal short-circuit test in
Annex C may be conducted as an alternative to the forced internal short-circuit test in 6.4.4.2.1.
___________
Second edition under preparation. Stage at the time of publication: IEC FDIS 62619:2021.
– 16 – IEC 62660-3:2022 © IEC 2022
6.4.4.3 Acceptance criteria
During the test, the cell shall exhibit no evidence of fire or explosion.
Annex A
(informative)
Operating region of cells for safe use
A.1 General
This annex explains how to determine the operating region of the cell to ensure the safe use of
the cell. The operating region is specified by the charging conditions such as the upper limit of
charging voltage and cell temperature, which ensure the safety of cells.
The cell manufacturers should stipulate the information on the operating region in the
specification of the cell, as part of the guidance on safety precautions to be provided to their
customers, such as the manufacturers of battery packs and systems. A suitable protection
device and function should also be provided in the battery control system, for possible failure
of the charge control.
The limits of the operating region are specified for the minimum safety and are different from
the charging voltage and temperature specified to optimize the performance of the cell (such
as cycle life).
A.2 Charging conditions for safe use
A.2.1 General
In order to ensure the safe use of cells, the cell manufacturers should set the upper limit of the
voltage and the temperature of cell to be applied during charging. The cell should be charged
within a predefined temperature range (standard temperature range) at the voltage not
exceeding the upper limit. The cell manufacturer may also set a temperature range higher or
lower than the standard temperature range, provided that the safety measures, such as lowered
charging voltage, are taken. The operating region means such range of voltage and temperature
where the cell can be used safely. The maximum charging current and the lower limit of the
discharging voltage may also be set for the operating region.
A newly developed cell can apply the same operating region as the original cell, if it has the
same electrode material, thickness, design, and separator as the original cell, and less than
120 % of the capacity of the original cell. The new cell can be considered as the same product
series cell.
A.2.2 Consideration on charging voltage
The charging voltage is applied for cells so as to promote the chemical reaction during charging.
However, if the charging voltage is too high, excessive chemical reactions or side reactions
occur, and the cell becomes thermally unstable. Consequently, it is essential that the charging
voltage never exceeds the value specified by the cell manufacturer (i.e. the upper limit of
charging voltage). When a cell is charged at a higher voltage than the upper limit charging
voltage, excess amount of lithium-ion is deintercalated from the positive electrode active
material, and its crystalline structure tends to collapse. In these conditions, when an internal
short-circuit occurs, thermal runaway can occur more easily than it does for cells charged in
the predefined operating region. Consequently, the cells should never
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