IEC 62660-3:2016

IEC 62660-3 ®
Edition 1.0 2016-08
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 1.0 2016-08
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 978-2-8322-3576-8

– 2 – IEC 62660-3:2016 © IEC 2016
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
2 Normative references. 7
3 Terms and definitions . 8
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 . 10
4.2.3 Current measurement. 10
4.2.4 Temperature measurements . 10
4.2.5 Other measurements . 10
4.3 Tolerance. 10
4.4 Test temperature . 11
5 Electrical measurement . 11
5.1 General charge conditions . 11
5.2 Capacity . 11
5.3 SOC adjustment . 11
6 Safety tests . 12
6.1 General . 12
6.2 Mechanical tests . 12
6.2.1 Vibration . 12
6.2.2 Mechanical shock . 12
6.2.3 Crush . 13
6.3 Thermal test . 14
6.3.1 High temperature endurance . 14
6.3.2 Temperature cycling . 14
6.4 Electrical tests . 14
6.4.1 External short circuit . 14
6.4.2 Overcharge . 15
6.4.3 Forced discharge . 15
6.4.4 Internal short circuit test . 15
Annex A (informative) Operating region of cells for safe use . 18
A.1 General . 18
A.2 Charging conditions for safe use. 18
A.2.1 General . 18
A.2.2 Consideration on charging voltage . 18
A.2.3 Consideration on temperature . 19
A.3 Example of operating region . 19
Annex B (informative) Explanation for the internal short-circuit test . 22
B.1 General concept . 22
B.2 Internal short circuit caused by particle contamination . 22
Bibliography . 24

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 . 20
Figure A.2 – An example of operating region for discharging of typical lithium-ion cells . 21

Table B.1 – Examples of the internal short circuit of cell . 23

– 4 – IEC 62660-3:2016 © IEC 2016
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
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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
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3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
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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.
International Standard IEC 62660-3 has been prepared by IEC technical committee 21:
Secondary cells and batteries.
The text of this standard is based on the following documents:
FDIS Report on voting
21/890/FDIS 21/897/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.

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 publication will remain unchanged until
the stability date indicated on the IEC website under "http://webstore.iec.ch" in the data
related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
IMPORTANT – The 'colour inside' logo on the cover page of this publication 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 62660-3:2016 © IEC 2016
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 the acceptance criteria for safety
performance of secondary lithium-ion cells and cell blocks used for the 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 International Standard intends to determine 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
standard 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
standard.
NOTE 3 The safety performance requirements for lithium-ion battery packs and systems are defined in
ISO 12405-3. The specifications and safety requirements for lithium-ion battery packs and systems of electrically
propelled mopeds and motorcycles are defined in ISO 18243 (under development). IEC 62619 (under development)
covers the safety requirements for the lithium ion cells and batteries for industrial applications including forklift
trucks, golf carts, and automated guided vehicles.
NOTE 4 Information on the cell operating region is provided in Annex A.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and
are indispensable for its application. 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
IEC 62660-2:2010, Secondary lithium-ion cells for the propulsion of electric road vehicles –
Part 2: Reliability and abuse testing
———————
Under preparation. Stage at the time of publication: IEC/CDV 62619:2015

– 8 – IEC 62660-3:2016 © IEC 2016
3 Terms and definitions
For the purposes of this standard, the terms and definitions given in IEC 60050-482, as well
as the following apply.
3.1
battery electric vehicle
BEV
electric vehicle with only a traction battery as power source for vehicle propulsion
3.2
cell block
a group of cells connected together in parallel configuration with or without protective devices,
e.g. fuse or positive temperature coefficient resistor (PTC), not yet fitted with its final housing,
terminal arrangement and electronic control device
3.3
explosion
failure that occurs when a cell container, if any, opens violently and major components are
forcibly expelled
3.4
fire
emission of flames from a cell or cell block
3.5
hybrid electric vehicle
HEV
vehicle with both a rechargeable energy storage system and a fuelled power source for
propulsion
3.6
internal short circuit
unintentional electrical connection between the negative and positive electrodes inside a cell
3.7
leakage
visible escape of liquid electrolyte from a part except vent, such as casing, sealing part and/or
terminals
3.8
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.]
3.9
rated capacity
quantity of electricity C Ah (ampere-hours) for BEV and C Ah for HEV declared by the
3 1
manufacturer
3.10
reference test current
I
t
current in amperes 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
3.11
room temperature
temperature of 25 °C ± 2 K
3.12
rupture
mechanical failure of a container case of cell induced by an internal or external cause,
resulting in exposure or spillage but not ejection of materials
3.13
secondary lithium-ion cell
cell
secondary single cell whose electrical energy is derived from the insertion/extraction reactions
of lithium-ions between the anode and the cathode
Note 1 to entry: The secondary cell is a basic manufactured unit providing a source of electrical energy by direct
conversion of chemical energy. The cell consists of electrodes, separators, electrolyte, a container and terminals,
and 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.
3.14
state of charge
SOC
available capacity in a battery expressed as a percentage of rated capacity
3.15
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
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.
4.2 Measuring instruments
4.2.1 Range of measuring devices
The instruments used shall enable the voltage and current values 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.

– 10 – IEC 62660-3:2016 © IEC 2016
4.2.2 Voltage measurement
The resistance of the voltmeters used shall be at least 1 M Ω/V.
4.2.3 Current measurement
The entire assembly of the ammeter, the shunt and the 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 manufacturer shall be followed.
Prismatic or flat cell
Cylindrical cell
Temperature measuring device
Cell Cell
Thermal insulating material
IEC
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 that 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 these 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.
Cell
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 Test temperature
If not otherwise defined, before each test the cell has to be stabilized at the test temperature
for a minimum of 12 h. This period can be reduced if thermal equilibrium is reached. Thermal
equilibrium 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 standard, 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 voltage
t t
specified by the manufacturer. Then, the cell shall be charged according to the charging
method declared by the manufacturer at room temperature.
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 steps.
Step 1 – The cell shall be charged in accordance with 5.1.
After recharge, the cell temperature shall be stabilized in accordance with 4.4.
Step 2 – The cell shall be discharged at the room temperature at a constant current of 1/3 I
t
(A) for BEV application and 1 I (A) for HEV application to the end-of-discharge voltage that is
t
provided by the manufacturer.
The method of designation of test current I is defined in IEC 61434. See also 3.9.
t
Step 3 – Measure the discharge endurance duration until the specified end-of-discharge
voltage is reached, and calculate the capacity of cell expressed in Ah up to three significant
figures.
5.3 SOC adjustment
The test cells shall be charged as specified below. The SOC adjustment is the procedure to
be followed for preparing cells to the various SOCs for the tests in this standard.
Step 1 – The cell shall be charged in accordance with 5.1.
Step 2 – The cell shall be left at rest at room temperature in accordance with 4.4.
Step 3 – The cell shall be discharged at a constant current of 1/3 I (A) for BEV application
t
and 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 the SOC (%) to be adjusted for each test.

– 12 – IEC 62660-3:2016 © IEC 2016
6 Safety tests
6.1 General
For all the tests specified in this clause, the test installation shall be reported including the
method used for fixing and wiring the cell.
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
manufacturer and the customer. A cell block may be used for testing in place of a single cell
according to the agreement between the manufacturer and the customer.
The number and type of test sample (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
standard.
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 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.
6.2.2 Mechanical shock
6.2.2.1 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.
6.2.2.2 Test
The test shall be performed in accordance with 6.1.2.1 of IEC 62660-2:2010.
6.2.2.3 Acceptance criteria
During the test, the cell shall exhibit no evidence of leakage, venting, rupture, fire or explosion.

6.2.3 Crush
6.2.3.1 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.
6.2.3.2 Test
The test shall be performed as follows.
a) Adjust the SOC of cell to 100 % for BEV application and 80 % for HEV application in
accordance with 5.3.
b) The cell shall be placed on an insulated rigid flat supporting surface, and shall be applied
a force 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 the layered face of the positive and negative electrodes
inside 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.
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 is sooner.
Crushing tool:
Crushing tool:
Hemisphere
Semicircular bar
Prismatic cell
Cylindrical cell
: Crushing direction
IEC IEC
a) Example for cylindrical cell b) Example for prismatic cell
Figure 2 – Example of crush test
6.2.3.3 Acceptance criteria
During the test, the cell shall exhibit no evidence of fire or explosion.

– 14 – IEC 62660-3:2016 © IEC 2016
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.
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 6.2.2.1.1 of IEC 62660-2:2010.
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 6.3.1.1 of IEC 62660-2:2010.

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 for BEV
t
application and 5 I for HEV application at room temperature using a power supply
t
sufficient to provide the constant charging current. The overcharge test shall be
discontinued when the voltage of the cell reaches 120 % of the maximum voltage
specified by the manufacturer, or the quantity of electricity applied to the cell reaches the
equivalent of 130 % SOC, whichever comes first.
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 over-discharge 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
manufacturer, or the cell is discharged for 30 min, whichever is 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 caused by the
contamination of 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.

– 16 – IEC 62660-3:2016 © IEC 2016
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 the single layer shall be
confirmed. The prescribed 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 the single layer.
The case and electrodes of the cell shall not be crushed. The modification shall be recorded.
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 the cell, as long as the test result is not
influenced.
NOTE 1 The internal short circuit of a single layer can be confirmed usually by the voltage drop of a few mV.
NOTE 2 In the event that the aluminium foil of the positive electrode is exposed at the outer turn, and 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
be checked by the design review, FMEA, etc. according to the agreement between the customer and the cell
supplier.
6.4.4.2.2 Alternative tests
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).
shall be
c) Approximately the same short circuited area as that of 7.3.2 b) of IEC 62619:—
simulated.
d) The short circuited locations in the cell shall be the same as described in 6.4.4.2.1.
e) The test shall be repeatable (see Table 1 of IEC 62619:— ).
The detailed test conditions and parameters of an alternative test shall be adjusted before the
test according to the agreement between the customer and the cell manufacturer, so that the
above criteria can be satisfied. The test result shall be evaluated by the disassembly of the
cell, X-ray observation, etc.
If the test result shows an internal short circuit of more than one layer, or a larger short-
circuited area, the test may be deemed as a valid alternative test, provided that the
acceptance criteria in 6.4.4.3 are satisfied. The failure in an alternative test does not mean
the failure in the test of 6.4.4.2.1, because the test condition of the alternative test may be
more severe than the prescribed criteria.
NOTE 1 In case the internal short circuit cannot be simulated, the test is invalid and the test data are recorded.
———————
Under preparation. Stage at the time of publication: IEC/CDV 62619:2015
Under preparation. Stage at the time of publication: IEC/CDV 62619:2015
Under preparation. Stage at the time of publication: IEC/CDV 62619:2015

NOTE 2 Examples of candidate alternative tests are recorded in IEC TR 62660-4 (under development).
6.4.4.2.3 Alternative to test on cell
In the particular case that the mitigation of the risk linked to the thermal runaway is obtained
at a higher level than the cell level (i.e. cell block and module, battery pack and system), the
internal short-circuit tests at cell level may be replaced by an alternative such as propagation
test for the safety demonstration of the battery system, if agreed between the customer and
the supplier. As one of the alternative methods to the internal short-circuit test, the
propagation test for the cell block and module is specified in IEC 62619.
NOTE: The propagation test on the battery pack and system is under consideration for ISO 12405-3.
6.4.4.3 Acceptance criteria
During the test, the cell shall exhibit no evidence of fire or explosion.

– 18 – IEC 62660-3:2016 © IEC 2016
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 cells, for the safety precautions to the 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 to allow for a possible failure of the charge control.
The limits of the operating region are specified for minimum safety, and different from the
charging voltage and temperature 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 a voltage not
exceeding the upper limit.
...