Secondary cells and batteries containing alkaline or other non-acid electrolytes - Secondary lithium cells and batteries for portable applications - Part 4: Coin secondary lithium cells, and batteries made from them

IEC 61960-4:2020 specifies performance tests, designations, markings, dimensions and other requirements for coin secondary lithium cells and batteries for portable applications and backup power supply such as memory backup applications.
The objective of this document is to provide the purchasers and users of coin secondary lithium cells and batteries with a set of criteria with which they can assess the performance of coin secondary lithium cells and batteries offered by various manufacturers.
This document defines a minimum required level of performance and a standardized methodology by which testing is performed and the results of this testing reported to the user. Hence, users will be able to establish the viability of commercially available cells and batteries via the declared specification and thus be able to select the cell or battery best suited for their intended application.
This document covers coin secondary lithium cells and batteries with a range of chemistries. Each electrochemical couple has a characteristic voltage range over which, during discharge, it releases its electrical capacity, a characteristic nominal voltage and a characteristic end-of-discharge voltage. Users of coin secondary lithium cells and batteries are requested to consult the manufacturer for advice.
This document also provides guidelines for designers of equipment using lithium batteries.

Accumulateurs alcalins et autres accumulateurs à électrolyte non acide - Accumulateurs au lithium pour applications portables - Partie 4: Éléments et batteries d’accumulateurs boutons au lithium

L'IEC 61960-4:2020 spécifie les essais de performance, les désignations, les marquages, les dimensions et autres exigences pour les éléments et batteries d'accumulateurs boutons au lithium destinés aux applications portables et d'alimentation de secours telles que les applications de sauvegarde de mémoire.
L'objectif du présent document est de fournir aux acheteurs et aux utilisateurs d'éléments et batteries d'accumulateurs boutons au lithium un ensemble de critères au moyen desquels ils peuvent évaluer la performance des différents accumulateurs de ce type proposés par différents fabricants.
Le présent document définit un niveau d'exigence minimale de performance et une méthodologie normalisée par laquelle sont réalisés les essais dont les résultats sont mis à la disposition de l'utilisateur. Les utilisateurs sont alors en mesure d'apprécier par eux-mêmes la viabilité des accumulateurs disponibles dans le commerce au moyen de la spécification déclarée et donc de sélectionner l'élément ou la batterie le ou la mieux adapté(e) à l'application prévue.
Le présent document concerne les éléments et batteries d'accumulateurs boutons au lithium dans une large gamme de couples électrochimiques. Chaque couple électrochimique possède une plage de tension caractéristique dans laquelle il restitue, en décharge, sa capacité emmagasinée, une tension nominale caractéristique et une tension de fin de décharge caractéristique. Il est demandé aux utilisateurs d'éléments et batteries d'accumulateurs boutons au lithium de prendre conseil auprès du fabricant.
Le présent document fournit également des lignes directrices pour les concepteurs d'équipements utilisant des batteries au lithium.

General Information

Status
Published
Publication Date
19-Apr-2020
Current Stage
PPUB - Publication issued
Completion Date
20-Apr-2020
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IEC 61960-4
Edition 1.0 2020-04
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE

Secondary cells and batteries containing alkaline or other non-acid electrolytes –

Secondary lithium cells and batteries for portable applications –
Part 4: Coin secondary lithium cells, and batteries made from them
Accumulateurs alcalins et autres accumulateurs à électrolyte non acide –
Accumulateurs au lithium pour applications portables –
Partie 4: Éléments et batteries d'accumulateurs boutons au lithium
IEC 61960-4:2020-04(en-fr)
---------------------- Page: 1 ----------------------
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---------------------- Page: 2 ----------------------
IEC 61960-4
Edition 1.0 2020-04
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE

Secondary cells and batteries containing alkaline or other non-acid electrolytes –

Secondary lithium cells and batteries for portable applications –
Part 4: Coin secondary lithium cells, and batteries made from them
Accumulateurs alcalins et autres accumulateurs à électrolyte non acide –
Accumulateurs au lithium pour applications portables –
Partie 4: Éléments et batteries d'accumulateurs boutons au lithium
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.220.99 ISBN 978-2-8322-8069-0

Warning! Make sure that you obtained this publication from an authorized distributor.

Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agréé.

® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale
---------------------- Page: 3 ----------------------
– 2 – IEC 61960-4:2020 © IEC 2020
CONTENTS

FOREWORD ........................................................................................................................... 3

1 Scope .............................................................................................................................. 5

2 Normative references ...................................................................................................... 5

3 Terms and definitions ...................................................................................................... 5

4 Parameter measurement tolerances ................................................................................ 7

5 Cell designation and marking ........................................................................................... 7

5.1 Cell designation ...................................................................................................... 7

5.2 Marking ................................................................................................................... 9

5.2.1 General ........................................................................................................... 9

5.2.2 Small cells or batteries .................................................................................... 9

6 Electrical tests ................................................................................................................. 9

6.1 General ................................................................................................................... 9

6.2 Charging procedure for test purposes ................................................................... 10

6.3 Discharge performance ......................................................................................... 11

6.4 Charge (capacity) recovery after long-term storage ............................................... 12

6.5 Endurance in cycles .............................................................................................. 12

6.6 Cell or battery internal resistance (AC resistance) ................................................. 13

6.6.1 General ......................................................................................................... 13

6.6.2 Test – General ............................................................................................... 13

6.6.3 Measurement ................................................................................................. 13

6.6.4 Acceptance criterion ...................................................................................... 14

7 Differentiation ................................................................................................................ 14

Annex A (informative) Guidelines for designers of equipment using lithium batteries ............ 15

Bibliography .......................................................................................................................... 16

Figure 1 – Dimensional characteristics .................................................................................... 8

Figure 2 – Sample sizes and sequence of tests .................................................................... 10

Table 1 – Electrochemical systems in current practical use ..................................................... 8

Table 2 – Examples of recommended upper limit charge voltage .......................................... 11

Table 3 – Recommended end-of-discharge voltage limit ....................................................... 11

Table 4 – Minimum number of cycles .................................................................................... 13

Table A.1 – Equipment design guidelines .............................................................................. 15

---------------------- Page: 4 ----------------------
IEC 61960-4:2020 © IEC 2020 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
SECONDARY CELLS AND BATTERIES CONTAINING ALKALINE OR
OTHER NON-ACID ELECTROLYTES – SECONDARY LITHIUM CELLS
AND BATTERIES FOR PORTABLE APPLICATIONS –
Part 4: Coin secondary lithium cells, and batteries made from them
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,

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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 61960-4 has been prepared by subcommittee 21A: Secondary cells

and batteries containing alkaline or other non-acid electrolytes, of IEC technical committee 21:

Secondary cells and batteries.
The text of this International Standard is based on the following documents:
FDIS Report on voting
21A/725/FDIS 21A/726/RVD

Full information on the voting for the approval of this International Standard 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.

---------------------- Page: 5 ----------------------
– 4 – IEC 61960-4:2020 © IEC 2020

A list of all parts in the IEC 61960 series, published under the general title Secondary cells and

batteries containing alkaline or other non-acid electrolytes – Secondary lithium cells and

batteries for portable applications, 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.
---------------------- Page: 6 ----------------------
IEC 61960-4:2020 © IEC 2020 – 5 –
SECONDARY CELLS AND BATTERIES CONTAINING ALKALINE OR
OTHER NON-ACID ELECTROLYTES – SECONDARY LITHIUM CELLS
AND BATTERIES FOR PORTABLE APPLICATIONS –
Part 4: Coin secondary lithium cells, and batteries made from them
1 Scope

This part of IEC 61960 specifies performance tests, designations, markings, dimensions and

other requirements for coin secondary lithium cells and batteries for portable applications and

backup power supply such as memory backup applications.

The objective of this document is to provide the purchasers and users of coin secondary lithium

cells and batteries with a set of criteria with which they can assess the performance of coin

secondary lithium cells and batteries offered by various manufacturers.
This document defines a minimum required level of performance and a standardized

methodology by which testing is performed and the results of this testing reported to the user.

Hence, users will be able to establish the viability of commercially available cells and batteries

via the declared specification and thus be able to select the cell or battery best suited for their

intended application.

This document covers coin secondary lithium cells and batteries with a range of chemistries.

Each electrochemical couple has a characteristic voltage range over which, during discharge,

it releases its electrical capacity, a characteristic nominal voltage and a characteristic end-of-

discharge voltage. Users of coin secondary lithium cells and batteries are requested to consult

the manufacturer for advice.

This document also provides guidelines for designers of equipment using lithium batteries (see

Annex A).
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 60050-482:2004, International Electrotechnical Vocabulary (IEV) – Part 482: Primary and

secondary cells and batteries

IEC 62133-2:2017, Secondary cells and batteries containing alkaline or other non-acid

electrolytes – Safety requirements for portable sealed secondary cells, and for batteries made

from them, for use in portable applications – Part 2: Lithium systems
3 Terms and definitions

For the purposes of this document, the terms and definitions given in IEC 60050-482 and the

following apply.
---------------------- Page: 7 ----------------------
– 6 – IEC 61960-4:2020 © IEC 2020

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
charge recovery
capacity recovery

capacity that a cell or battery can deliver with subsequent recharge, after storage at a specific

temperature, for a specific time, as a percentage of the rated capacity
3.2
coin cell
coin battery

small round cell or battery where the overall height is less than the diameter, containing

non-aqueous electrolyte
3.3
end-of-discharge voltage

specified closed circuit voltage at which a discharge of a cell or battery is terminated

[SOURCE: IEC 60050-482:2004, 482-03-30, modified – The synonyms "final voltage", "cut-off

voltage", and "end-point voltage" have been omitted and the words "closed circuit" and "cell"

have been added to the definition.]
3.4
nominal voltage

suitable approximate value of voltage used to designate or identify a cell, or a battery

Note 1 to entry: The nominal voltages of coin secondary lithium cells are shown in Table 1.

[SOURCE: IEC 60050-482:2004, 482-03-31, modified – "electrochemical system" has been

omitted from the definition and the note has been added.]
3.5
rated capacity

quantity of electricity mAh (milliampere-hours) that a single cell or battery can deliver, when

charged, stored and discharged under specified conditions and declared by the manufacturer

3.6
secondary lithium battery

unit which incorporates one or more secondary lithium cells and which is ready for use

Note 1 to entry: This unit incorporates adequate housing and a terminal arrangement and may have electronic

control devices.
3.7
secondary lithium cell

secondary cell whose electrical energy is derived from oxidation and the reduction of lithium

Note 1 to entry: This cell is not ready for use in an application because it is not yet fitted with its final housing,

terminal arrangement and electronic control device.
---------------------- Page: 8 ----------------------
IEC 61960-4:2020 © IEC 2020 – 7 –
4 Parameter measurement tolerances

The overall accuracy of controlled or measured values, relative to the specified or actual values,

shall be within the following tolerances:
a) ±1 % for voltage;
b) ±1 % for current;
c) ±1 % for capacity;
d) ±2 °C for temperature;
e) ±0,1 % for time;
f) ±0,1 mm for dimensions.

These tolerances comprise the combined accuracy of the measuring instruments, the

measurement techniques used, and all other sources of error in the test procedure.

The details of the instrumentation used shall be provided in any report of results.

5 Cell designation and marking
5.1 Cell designation
Cells shall be designated with the following form:
A A DDHH
1 2
where
A designates the positive electrode system in which:
C or U is lithium cobalt oxide
M is lithium manganese oxide
NB is niobium oxide
V is vanadium oxide
T is lithium titanium oxide
A designates the negative electrode system in which:
C is carbon
L is lithium aluminium alloy
S is lithium silicon oxide/alloy
T or TL is lithium titanium oxide
DD designates the diameter in mm
HH designates the height in 1/10 of mm

The requirements concerning code letters on electrochemical systems are given in Table 1.

---------------------- Page: 9 ----------------------
– 8 – IEC 61960-4:2020 © IEC 2020
Table 1 – Electrochemical systems in current practical use
Nominal
voltage
Positive electrode Electrolyte Negative electrode
Code letters
(V)
Lithium cobalt oxide Carbon 3,7 UC
Lithium cobalt oxide Lithium titanium oxide 3,0 UT
Vanadium oxide Lithium aluminium alloy 3,0 VL
Lithium manganese oxide Lithium aluminium alloy 3,0 ML
Lithium manganese oxide Lithium silicon oxide/alloy 3,0 MS
Non-aqueous
Lithium cobalt oxide solution with Lithium titanium oxide 2,3 CTL
lithium salt
Niobium oxide Lithium aluminium alloy 2,0 NBL
Lithium manganese oxide Lithium titanium oxide 1,5 MT
Lithium titanium oxide Lithium-carbon compound 1,5 TC
Lithium titanium oxide Lithium aluminium alloy 1,5 TL
Lithium titanium oxide Lithium silicon oxide 1,5 TS

The above code letters are given as examples. Each positive electrode and negative electrode shall be designated with

one or two letters. Any code letter can be decided on by agreement between the manufacturer and user when there is a

same chemistry which has different nominal voltages.
Key
h overall height of the cell
d diameter of the cell
Figure 1 – Dimensional characteristics

Coin secondary lithium cells complying with this document shall be designated by the following

system consisting of code letters and numbers. For the electrochemical systems, the code

letters shall be expressed using two letters (a maximum of three letters), followed by diameter

and height expressed in that order. See Figure 1.

EXAMPLE ML 1220

Electrochemical systems code letters
Dimensions: d in millimetres
Dimensions: h in 1/10 of millimetres

NOTE Notwithstanding the above specification, other designations can be used according to an agreement between

manufacturer and user.
---------------------- Page: 10 ----------------------
IEC 61960-4:2020 © IEC 2020 – 9 –
5.2 Marking
5.2.1 General

With the exception of small cells or batteries (see 5.2.2), each cell or battery shall be marked

with the following information:
a) cell designation, IEC or common;
b) the year and month or week of manufacture (may be given in code);
c) polarity of the positive (+) terminal;
d) nominal voltage;
e) name or trade mark of the manufacturer or supplier;
f) cautionary advice;
g) caution for ingestion of swallowable cells and batteries (see IEC 60086-4);

h) combination of "secondary (rechargeable)" and "Li", or "secondary (rechargeable)" and "Li-

ion".
5.2.2 Small cells or batteries

For cells or batteries that fit entirely within the ingestion gauge (Figure 3 in IEC 62133-2:2017),

the designation specified in 5.2.1 a) and the polarity specified in 5.2.1 c) shall be marked on

the cell or battery.

For cells or batteries with an internal AC resistance less than or equal to 3 Ω, intended to be

user replaceable or not contained in the equipment, the additional marking of 5.2.1 h) shall be

marked on the cell or battery.

All other information shown in 5.2.1 should be given in the specification sheet, or in the

instruction manual or on the immediate package instead of on the cell or battery.

6 Electrical tests
6.1 General

Only cell or battery samples which are less than two months (60 days) old from the date of

manufacture shall be used for the tests specified in this document.

Unless otherwise stated in this document, the following tests shall be done in an ambient

temperature of 20 °C ± 5 °C.

Tested cells or batteries should not exceed the upper limit charge voltage or end-of-discharge

voltage limit during the test.

Coin secondary lithium cells or batteries have different characteristics and features in terms of

voltage, discharge performance, capacity recovery after storage, and cycling depending on their

chemistries. Therefore, conditions specified by the manufacturer shall be used in order to make

the most of cell or battery characteristics.
The sample sizes and the sequence of the tests are described in Figure 2.
---------------------- Page: 11 ----------------------
– 10 – IEC 61960-4:2020 © IEC 2020
Figure 2 – Sample sizes and sequence of tests
6.2 Charging procedure for test purposes

There are two different charging methods for the coin secondary lithium cells or batteries:

constant voltage charge and constant current charge. The charge method and conditions

specified by the manufacturer shall be used. When such information is not available, the charge

voltage shall be in accordance with Table 2.
---------------------- Page: 12 ----------------------
IEC 61960-4:2020 © IEC 2020 – 11 –
Table 2 – Examples of recommended upper limit charge voltage
Recommended upper limit
Code letters
charge voltage
UC 4,25 V
UT 3,2 V
VL 3,55 V
ML 3,2 V
MS 3,3 V
CTL 2,7 V
NBL 2,5 V
MT 2,6 V
TC 3,15 V
TL 1,7 V
TS 3,0 V
6.3 Discharge performance
This test verifies the rated capacity of a cell or battery at 20 °C.
Step 1: The cell or battery shall be charged in accordance with 6.2.

Step 2: The cell or battery shall be stored in an ambient temperature of 20 °C ± 5 °C, for not

less than 1 h and not more than 4 h.

Step 3: The cell or battery shall be discharged, in an ambient temperature of 20 °C ± 5 °C, at a

constant current or constant resistance to the end-of-discharge voltage specified by the

manufacturer. When such information is not available, the recommended end-of-discharge

voltage limits are shown in Table 3.

Step 4: The capacity (mAh) delivered during step 3 shall be not less than the rated capacity

declared by the manufacturer.
Table 3 – Recommended end-of-discharge voltage limit
Recommended end-of-discharge
Code letters
voltage limit
UC 2,5 V
UT 2,0 V
VL 2,5 V
ML 2,0 V
MS 2,0 V
CTL 2,0 V
NBL 1,0 V
MT 1,0 V
TC 0,5 V
TL 0,8 V
TS 1,0 V
---------------------- Page: 13 ----------------------
– 12 – IEC 61960-4:2020 © IEC 2020
6.4 Charge (capacity) recovery after long-term storage

This test verifies the capacity of a cell or battery after extended storage at 100 % state of charge,

followed by a subsequent charge.

Step 1: The cell or battery shall be charged in accordance with the specific conditions specified

by the manufacturer.
Step 2: The cell or battery shall be stored at 60 °C for 20 days.

Step 3: The cell or battery shall be stored, in an ambient temperature of 20 °C ± 5 °C, for not

less than 1 h and not more than 4 h.

Step 4: The cell or battery shall be discharged in an ambient temperature of 20 °C ± 5 °C, at

the discharge conditions specified by manufacturer, until its voltage is equal to the

manufacturer's specified end-of-discharge voltage. The cell or battery shall be charged before

discharge by the specific condition by the manufacturer.

Step 5: The capacity (mAh) delivered during step 4 shall be more than 50 % of its rated capacity.

6.5 Endurance in cycles
This test verifies the ability of charge-discharge cycle.

Step 1: The cell or battery shall be discharged, in an ambient temperature of 20 °C ± 5 °C, using

the method declared by the manufacturer.

Step 2: The cell or battery shall be continuously charged and discharged, in an ambient

temperature of 20 °C ± 5 °C.

The cell or battery shall be charged until its voltage is equal to the specified end-of-charge

voltage, or it shall be charged for the specified amount of time after its voltage is equal to the

specified end-of-charge voltage, using the method and conditions declared by the manufacturer.

The cell or battery shall be discharged in an ambient temperature of 20 °C ± 5 °C, until its

voltage is equal to the specified end-of-discharge voltage, or it shall be discharged for the

specified amount of time, using the method declared by the manufacturer.

The test shall be terminated when the discharge capacity reaches 50 % of its first cycle. The

result shall satisfy the minimum number of cycles in Table 4.
---------------------- Page: 14 ----------------------
IEC 61960-4:2020 © IEC 2020 – 13 –
Table 4 – Minimum number of cycles
Code letters Minimum number of cycles
UC 100
UT 100
VL 5
ML 5
MS 50
CTL 100
NBL 5
MT 100
TC 100
TL 5
TS 50
The test procedure in 6.5 is a representative and unified accelerated method
to cover various electrochemical systems, and actual charge-discharge
conditions may be different depending on each application. The above
minimum numbers of cycles are values tested according to the procedure in
6.5
...

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