IEC TR 62660-4:2017

Secondary lithium-ion cells for the propulsion of electric road vehicles - Part 4: Candidate alternative test methods for the internal short circuit test of IEC 62660-3

IEC TR 62660-4:2017(E) provides the test data on the candidate alternative test methods for the internal short circuit test according to 6.4.4.2.2 of IEC 62660-3:2016. The internal short circuit test in this document is intended to simulate an internal short circuit of a cell caused by the contamination of conductive particle, and to verify the safety performance of the cell under such conditions.
This document is applicable to the 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 does not cover cylindrical cells.

General Information

• Status: Published
• Publication Date: 12-Feb-2017
• ICS: 29.220.20 - Acid secondary cells and batteries
• Technical Committee: TC 21 - Secondary cells and batteries
• Current Stage: PPUB - Publication issued
• Start Date: 13-Feb-2017
• Completion Date: 04-Jan-2017

Standards Content (Sample)

IEC TR 62660-4 ®
Edition 1.0 2017-02
TECHNICAL
REPORT
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inside
Secondary lithium-ion cells for the propulsion of electric road vehicles –
Part 4: Candidate alternative test methods for the internal short circuit test of
IEC 62660-3
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IEC TR 62660-4 ®
Edition 1.0 2017-02
TECHNICAL
REPORT
colour
inside
Secondary lithium-ion cells for the propulsion of electric road vehicles –

Part 4: Candidate alternative test methods for the internal short circuit test of

IEC 62660-3
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.220.20 ISBN 978-2-8322-3715-1

– 2 – IEC TR 62660-4:2017 © IEC 2017
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 7
4 General provisions for alternative test . 7
5 Alternative test method . 8
5.1 Alternative test method description . 8
5.1.1 General . 8
5.1.2 Test preparation and test set-up . 8
5.1.3 Test execution . 10
5.1.4 Acceptance criteria . 11
Annex A (informative) Test data . 12
A.1 General . 12
A.2 Test data . 12
A.2.1 Test results . 12
A.2.2 Data of each test . 18

Figure 1 – Example of test setup 1 . 9
Figure 2 – Example of test setup 2 . 9
Figure 3 – Example of ceramic nail with Ni tip . 10
Figure 4 – Example of ceramic nail with Ni tip test . 10
Figure A.1 – Voltage and temperature of test 1-1 . 18
Figure A.2 – Voltage and temperature of test 1-2 . 18
Figure A.3 – Voltage and temperature of test 1-3 . 19
Figure A.4 – Voltage and temperature of test 2-1 . 19
Figure A.5 – Voltage and temperature of test 2-2 . 20
Figure A.6 – Voltage and temperature of test 2-3 . 20
Figure A.7 – Voltage and temperature of test 3-1 . 21
Figure A.8 – Voltage and temperature of test 3-2 . 21
Figure A.9 – ø3 mm ceramic nail with Ni tip . 22
Figure A.10 – Voltage and temperature of test 4 . 22
Figure A.11 – Voltage and temperature of test 5-1 . 23
Figure A.12 – Voltage and temperature of test 5-2 . 23
Figure A.13 – Voltage data of tests 6 . 24
Figure A.14 – Voltage data of tests 7 . 24
Figure A.15 – Voltage data of tests 8 . 25
Figure A.16 – Voltage data of tests 9 . 25
Figure A.17 – Voltage data of tests 10-1 . 26
Figure A.18 – Voltage data of tests 10-2 . 26
Figure A.19 – Voltage data of test 11-1 . 27
Figure A.20 – Voltage data of test 11-2 . 27

Figure A.21 – Voltage data of test 12-1 . 28
Figure A.22 – Voltage data of test 12-2 . 28
Figure A.23 – Voltage data of test 12-3 . 28
Figure A.24 – Voltage data of test 12-4 . 29
Figure A.25 – Voltage data of test 12-5 . 29
Figure A.26 – Voltage data of test 12-6 . 29
Figure A.27 – Voltage data of test 12-7 . 30
Figure A.28 – Voltage data of test 13 . 30
Figure A.29 – Voltage data of test 14-1 . 31
Figure A.30 – Voltage data of test 14-2 . 31
Figure A.31 – Voltage data of test 14-3 . 31
Figure A.32 – Voltage data of test 14-4 . 32
Figure A.33 – Voltage data of test 14-5 . 32
Figure A.34 – Voltage data of tests 15 . 33
Figure A.35 – Voltage data of tests 16 . 34

Table 1 – Recommended test specifications . 8
Table A.1 – Internal short circuit test results . 13

– 4 – IEC TR 62660-4:2017 © IEC 2017
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
SECONDARY LITHIUM-ION CELLS FOR THE PROPULSION
OF ELECTRIC ROAD VEHICLES –
Part 4: Candidate alternative test methods
for the internal short circuit test of IEC 62660-3

FOREWORD
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The main task of IEC technical committees is to prepare International Standards. However, a
technical committee may propose the publication of a Technical Report when it has collected
data of a different kind from that which is normally published as an International Standard, for
example "state of the art".
IEC TR 62660-4, which is a Technical Report, has been prepared by IEC technical committee
21: Secondary cells and batteries.

The text of this Technical Report is based on the following documents:
Enquiry draft Report on voting
21/891/DTR 21/899/RVC
Full information on the voting for the approval of this Technical Report can be found in the
report on voting indicated in the above table.
This document 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 document will remain unchanged until the
stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to
the specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
A bilingual version of this publication may be issued at a later date.

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– 6 – IEC TR 62660-4:2017 © IEC 2017
INTRODUCTION
IEC 62660-3 provides the 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). IEC 62660-3
specifies the internal short circuit test to simulate an internal short circuit of a cell caused by
the contamination of conductive particle, based on IEC 62619. Because the test method
based on IEC 62619 requires opening of the cell and care to be taken, the industry needs
alternative test methods that could also be applied under certain conditions. This document
provides candidates of alternative test procedures.
NOTE This test is to be conducted in a facility suitable to contain the potential for hazardous reactions up to and
including an explosion and with staff trained to manage the risks.

SECONDARY LITHIUM-ION CELLS FOR THE PROPULSION
OF ELECTRIC ROAD VEHICLES –
Part 4: Candidate alternative test methods
for the internal short circuit test of IEC 62660-3

1 Scope
This Part of IEC 62660 provides the test data on the candidate alternative test methods for
the internal short circuit test according to 6.4.4.2.2 of IEC 62660-3:2016. The internal short
circuit test in this document is intended to simulate an internal short circuit of a cell caused by
the contamination of conductive particle, and to verify the safety performance of the cell under
such conditions.
This document is applicable to the 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 This document does not cover cylindrical cells.
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 62619:2017, 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 62660-3:2016, Secondary lithium-ion cells for the propulsion of electric road vehicles –
Part 3: Safety requirements
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 62660-3 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.
4 General provisions for alternative test
The internal short circuit test is specified in 6.4.4.2.1 of IEC 62660-3:2016. The other test
methods to simulate the internal short circuit of cell caused by the contamination of
conductive particle may be selected if the following criteria are satisfied, and agreed between
the customer and the supplier:

– 8 – IEC TR 62660-4:2017 © IEC 2017
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 positive and negative electrode shall be simulated
(target).
c) Approximately the same short circuited area as that of 7.3.2 b) of IEC 62619:2017 shall be
simulated.
d) The short circuited locations in the cell shall be the same as described in 6.4.4.2.1 of
IEC 62660-3:2016.
e) The test shall be repeatable (see Table 1 of IEC 62619:2017).
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 more than one layer internal short circuit, or larger short circuited area,
the test may be deemed as valid alternative test, provided that the acceptance criteria in
6.4.4.3 of IEC 62660-3:2016 are satisfied. The failure in an alternative test does not mean the
failure in the test according to 6.4.4.2.1 of IEC 62660-3:2016, because the test condition of
the alternative test may be more severe than the prescribed criteria.
NOTE In case the internal short circuit cannot be simulated, the test is invalid and the test data are reported.
5 Alternative test method
5.1 Alternative test method description
5.1.1 General
This subclause describes the test method of the indentation induced internal short circuit test
as a candidate of alternative test methods in Clause 4. Table 1 provides the recommended
test specifications of the test.
Table 1 – Recommended test specifications
Item Recommendation
Test temperature (temperature of the test bench and cell) 25 °C ± 5 °C
State of charge (SOC) of the cell Maximum SOC specified by the cell manufacturer
Press speed 0,1 mm/s or less
Press speed accuracy ± 0,01 mm/s
Position stability after pressurizing ± 0,02 mm
Maximum pressurizing capability 1 000 N or more
Pressure measuring method Directly measured with a load cell
Pressure measuring period 5 ms or less
Temperature measuring period 1 s or less
Voltage measuring period 5 ms or less
Time to stop the indenter after voltage drop is detected 100 ms or less

5.1.2 Test preparation and test set-up
5.1.2.1 Cell preparation
For flat or pouch cell, no preparation is needed.

For prismatic cell with hard casing, casing could be thinned or removed by an appropriate
method recommended by the cell manufacturer. Thinning or removal of casing should be
conducted before the charging of cell and SOC adjustment. This operation should be
conducted taking all the safety measures needed.
5.1.2.2 Test setup
The cell should be held in a manner not to move during the test. The cell should be
electrically isolated from test bench.
A flat or pouch cell requires a fixation device. Figure 1 and Figure 2 show examples of the
fixation device.
Press equipment
Load cell
Restraint
6 mm nonwoven fiberglass
(compressed to 3 mm)
Cell
Indenter
3 mm PTFE
IEC
Figure 1 – Example of test setup 1
Rubber sheet
Cell
Bakelite
IEC
Figure 2 – Example of test setup 2
5.1.2.3 Indenter device
5.1.2.3.1 General
Two types of indenter device, as defined in 5.1.2.3.2 and 5.1.2.3.3 are proposed in this
alternative test method.
5.1.2.3.2 Type 1: 3 mm ceramic nail
Type 1 indenter is a ceramic nail having a diameter of 3 mm ± 0,2 mm. The angle of the nail
tip should be 45° ± 3°. Figure 1 shows an example of the ceramic nail's orientation to the cell
electrode layers during the press.

– 10 – IEC TR 62660-4:2017 © IEC 2017
5.1.2.3.3 Type 2: 1 mm ceramic nail with Ni tip
Type 2 indenter is a ceramic nail having a diameter of 1 mm ± 0,1 mm with a nickel (Ni) tip of
0,35 mm in height. The angle of the Ni nail tip should be between 28° and 45°. See Figure 3
and Figure 4.
A ceramic nail with a Ni tip is suitable for a prismatic cell with a hard casing and a flat or
pouch cell.
The test using the Type 1 indenter is not applicable to the cells of which the casing is used as
a part of the electrodes. If the casing is removed, this test may be applicable.
Dimensions in millimetres
ø1 ±0,1
30°
IEC
Figure 3 – Example of ceramic nail with Ni tip
IEC
Figure 4 – Example of ceramic nail with Ni tip test
5.1.3 Test execution
The test should be conducted as follows:
a) Prepare the cell in accordance with 5.1.2.1.
0,35 ±0,05
b) Adjust the SOC of the cell in accordance with 5.3 of IEC 62660-3:2016, at the maximum
SOC specified by the cell manufacturer.
c) Fix the cell to the test setup in accordance with 5.1.2.2. The indenter device should be
selected according to 5.1.2.3, based on the agreement between the customer and the
supplier. The indenter should be placed perpendicular to the electrode layers of the cell.
The cell or the indenter should move along this perpendicular axis. The indentation
location should be the same as IEC 62660-3:2016.
d) Press the indenter to the cell, or press the cell up to the indenter, with a constant velocity
of less than 0,1 mm/s. Displacement of the indenter should be stopped when a voltage
drop of at least 5 mV is detected. It is acceptable to use a voltage drop of less than 5 mV
if a high accuracy voltage meter is used and the actual short location can be confirmed
with an inspection of the internal short location after the test. The accuracy of the voltage
meter should be reported. If the voltage drop of at least 5 mV is not detected until the
indenter is depressed to half the thickness of a cell, the test should be stopped and
considered as invalid, and the test should be conducted once again.
e) After the indentation stops, the indenter should remain in place until the end of the
observation period. During the test, the cell voltage, the force of the press, the
displacement of the press and the temperature of the cell should be recorded. The cell
temperature should be measured on the surface of the cell, at a distance of less than
25 mm from the centre of the indentation. Sampling time for voltage and pressure
recording should be 5 ms or less. Sampling time for other parameters recording should be
1 s or less.
5.1.4 Acceptance criteria
During the test and within 1 h of observation, the cell should exhibit no evidence of fire or
explosion.
– 12 – IEC TR 62660-4:2017 © IEC 2017
Annex A
(informative)
Test data
A.1 General
This annex provides information on the result of tests conducted according to Clause 5, and
of relevant comparison tests.
The reproducibility of each test result is confirmed on several cell designs. Further test data
need to be evaluated with cells that failed the test in 6.4.4.2.1 of IEC 62660-3:2016, etc.
A.2 Test data
A.2.1 Test results
Table A.1 shows the result of internal short circuit tests on several types of cells, using the
indenters in 5.1.2.3, and other types of indenters for comparison. The forced internal short
circuit (FISC) test in 6.4.4.2.1 of IEC 62660-3:2016 is also conducted as comparison test.
All cells in Table A.1 exhibited no evidence of fire or explosion, and met the acceptance
criteria in 5.1.4.
In most of the tests except FISC test, the number of short circuited layers is larger than one
layer, and also varies among the same cells.
Further data of each test are shown in A.2.2.

IEC TR 62660-4:2016 © IEC 2016 – 13 –

Table A.1 – Internal short circuit test results
Test Indenter type Cell Chemistry Type of cell Press Target Test result
No. or FISC or Capacity and case speed voltage
or Application thic
...