EN 61951-2:2017

SLOVENSKI STANDARD
01-september-2017
1DGRPHãþD
SIST EN 61951-2:2011
6HNXQGDUQLþOHQLLQEDWHULMH]DONDOQLPLDOLGUXJLPLQHNLVOLQVNLPLHOHNWUROLWL
6HNXQGDUQL]DWHVQMHQLþOHQLLQEDWHULMH]DSUHQRVQHQDSUDYHGHO1LNHOMNRYLQVNL
KLGULG
Secondary cells and batteries containing alkaline or other non-acid electrolytes -
Secondary sealed cells and batteries for portable applications - Part 2: Nickel-metal
hydride
Akkumulatoren und Batterien mit alkalischem oder anderen nichtsäurehaltigen
Elektrolyten - Tragbare wiederaufladbare gasdichte Einzelzellen - Teil 2: Nickel-
Metallhydrid
Accumulateurs alcalins et autres accumulateurs à électrolyte non acide - Accumulateurs
étanches pour applications portables - Partie 2: Nickel-métal hydrure
Ta slovenski standard je istoveten z: EN 61951-2:2017
ICS:
29.220.30 $ONDOQLVHNXQGDUQLþOHQLLQ Alkaline secondary cells and
EDWHULMH batteries
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN 61951-2
NORME EUROPÉENNE
EUROPÄISCHE NORM
June 2017
ICS 29.220.30 Supersedes EN 61951-2:2011
English Version
Secondary cells and batteries containing alkaline or other non
acid electrolytes - Secondary sealed cells and batteries for
portable applications - Part 2: Nickel-metal hydride
(IEC 61951-2:2017)
Accumulateurs alcalins et autres accumulateurs à Akkumulatoren und Batterien mit alkalischem oder anderen
électrolyte non acide - Accumulateurs étanches pour nichtsäurehaltigen Elektrolyten - Tragbare wiederaufladbare
applications portables - Partie 2: Nickel-métal hydrure gasdichte Einzelzellen - Teil 2: Nickel-Metallhydrid
(IEC 61951-2:2017) (IEC 61951-2:2017)
This European Standard was approved by CENELEC on 2017-04-26. CENELEC members are bound to comply with the CEN/CENELEC
Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.
Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC
Management Centre or to any CENELEC member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the
same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,
Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden,
Switzerland, Turkey and the United Kingdom.

European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2017 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN 61951-2:2017 E
European foreword
The text of document 21A/623/FDIS, future edition 4 of IEC 61951-2, prepared by SC 21A, Secondary
cells and batteries containing alkaline or other non-acid electrolytes, of IEC/TC 21 "Secondary cells
and batteries" was submitted to the IEC-CENELEC parallel vote and approved by CENELEC as
The following dates are fixed:
• latest date by which the document has to be (dop) 2018-01-26
implemented at national level by
publication of an identical national
standard or by endorsement
(dow) 2020-04-26
• latest date by which the national
standards conflicting with the
document have to be withdrawn
This document supersedes EN 61951-2:2011.

Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC shall not be held responsible for identifying any or all such patent rights
Endorsement notice.
The text of the International Standard IEC 61951-2:2017 was approved by CENELEC as a European
Standard without any modification.
In the official version, for Bibliography, the following notes have to be added for the standards indicated:

IEC 60051 (series) NOTE Harmonized as EN 60051 (series).
IEC 60086 (series) NOTE Harmonized as EN 60086 (series).
IEC 61434 NOTE Harmonized as EN 61434.

Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
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.
NOTE 1 When an International Publication has been modified by common modifications, indicated by (mod), the relevant

EN/HD applies.
NOTE 2 Up-to-date information on the latest versions of the European Standards listed in this annex is available here:
www.cenelec.eu.
Publication Year Title EN/HD Year
IEC 60050-482 2004 International Electrotechnical Vocabulary - -
(IEV) -- Part 482: Primary and secondary
cells and batteries
IEC 60086-1 -  Primary batteries - Part 1: General EN 60086-1 -
IEC 60086-2 -  Primary batteries - Part 2: Physical and EN 60086-2 -
electrical specifications
IEC 61959 -  Secondary cells and batteries containing EN 61959 -
alkaline or other non-acid electrolytes -
Mechanical tests for sealed portable
secondary cells and batteries
IEC 62133-1 -  Secondary cells and batteries containing EN 62133-1 -
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 1: Nickel systems
IEC 61951-2 ®
Edition 4.0 2017-03
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Secondary cells and batteries containing alkaline or other non-acid

electrolytes – Secondary sealed cells and batteries for portable applications –

Part 2: Nickel-metal hydride
Accumulateurs alcalins et autres accumulateurs à électrolyte non acide –

Accumulateurs étanches pour applications portables –

Partie 2: Nickel-métal hydrure

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.220.30 ISBN 978-2-8322-4011-3

– 2 – IEC 61951-2:2017 © IEC 2017
CONTENTS
FOREWORD . 5
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 7
4 Parameter measurement tolerances . 9
5 Cell and battery designation and marking . 10
5.1 Cell and battery designation . 10
5.1.1 Small prismatic cells and cylindrical cells . 10
5.1.2 Button cells. 11
5.1.3 Batteries . 12
5.2 Cell or battery termination . 12
5.3 Marking . 12
5.3.1 Small prismatic cells and cylindrical cells . 12
5.3.2 Button cells. 13
5.3.3 Batteries . 13
5.4 Exemption of wording. 13
6 Dimensions. 13
6.1 Small prismatic cells and cylindrical cells . 13
6.1.1 General . 13
6.1.2 Small prismatic cells . 14
6.1.3 Cylindrical cells . 14
6.2 Button cells . 16
6.3 9 V type nickel-metal hydride batteries . 17
7 Electrical tests . 18
7.1 General . 18
7.2 Charging procedure for test purposes . 18
7.2.1 Charging procedure for cell. 18
7.2.2 Charging procedure for battery . 18
7.3 Discharge performance . 18
7.3.1 General . 18
7.3.2 Discharge performance at 20 °C . 19
7.3.3 Discharge performance at 0 °C . 20
7.3.4 Discharge performance for rapid charge cells (R cells) . 21
7.4 Charge (capacity) retention . 21
7.5 Endurance . 22
7.5.1 Endurance in cycles. 22
7.5.2 Permanent charge endurance . 25
7.6 Charge acceptance at constant voltage . 28
7.7 Overcharge . 28
7.7.1 Small prismatic, L, M, H, X, LS or MS cylindrical, and button cells . 28
7.7.2 LT/LU, MT/MU or HT/HU cylindrical cells . 29
7.7.3 J cylindrical cells . 29
7.7.4 JT cylindrical cells . 29
7.7.5 R cylindrical cells . 30
7.8 Safety device operation . 30
7.9 Surface temperature limitation device operation (for S cell only) . 30

IEC 61951-2:2017 © IEC 2017 – 3 –
7.10 Storage . 31
7.10.1 Button cells or batteries, small prismatic cells or batteries, cylindrical
cells or batteries . 31
7.10.2 Button cells or batteries, small prismatic cells or batteries, cylindrical
cells or batteries (high recovery type) . 32
7.11 Charge acceptance at +55 °C for LT, MT or HT cylindrical cells . 33
7.12 Trickle charge acceptance for JT cylindrical cells . 34
7.13 Internal resistance . 34
7.13.1 General . 34
7.13.2 Measurement of the internal AC resistance . 35
7.13.3 Measurement of the internal DC resistance . 35
8 Mechanical tests . 36
9 Safety requirements . 36
10 Type approval and batch acceptance . 36
10.1 General . 36
10.2 Type approval . 36
10.2.1 Type approval for small prismatic cells and button cells . 36
10.2.2 Type approval for cylindrical cells . 40
10.2.3 Type approval for batteries . 42
10.3 Batch acceptance . 43
Bibliography . 45

Figure 1 – Jacketed cylindrical cells . 14
Figure 2 – Jacketed small prismatic cells . 14
Figure 3 – Jacketed cells dimensionally interchangeable with primary cells . 15
Figure 4 – Button cells . 17
Figure 5 – 9 V type nickel-metal hydride batteries . 17

Table 1 – Dimensions of jacketed small prismatic cells . 14
Table 2 – Dimensions of jacketed cylindrical cells dimensionally interchangeable with
primary cells . 15
Table 3 – Dimensions of jacketed cylindrical cells not dimensionally interchangeable
with primary cells . 16
Table 4 – Dimensions of button cells. 17
Table 5 – Dimensions of 9 V type nickel-metal hydride batteries . 18
Table 6 – Discharge performance at 20 °C for small prismatic cells and cylindrical cells . 19
Table 7 – Discharge performance at 20 °C for button cells . 19
Table 8 – Discharge performance at 20 °C for batteries . 20
Table 9 – Rated capacity (mAh) compliance test (example) . 20
Table 10 – Discharge performance at 0 °C for small prismatic cells and cylindrical cells . 21
Table 11 – Discharge performance at 0 °C for button cells . 21
Table 12 – Endurance in cycles for small prismatic, button and cylindrical cells not
dimensionally interchangeable with primary cells . 22
Table 13 – Endurance in cycles for H or X cells . 23
Table 14 – Endurance in cycles for X cells . 23
Table 15 – Endurance in cycles for HR or XR cells . 24

– 4 – IEC 61951-2:2017 © IEC 2017
Table 16 – Endurance in cycles for cylindrical cells dimensionally interchangeable with
primary cells . 24
Table 17 – Permanent charge endurance for L, M, H or X cells . 25
Table 18 – Permanent charge endurance for LT, MT or HT cells . 26
Table 19 – Permanent charge endurance for LU, MU or HU cells . 28
Table 20 – Overcharge at 0 °C . 29
Table 21 – Capacity deterioration due to storage period for cells or batteries . 32
Table 22 – Capacity deterioration due to storage period for cells or batteries (high
recovery type) . 33
Table 23 – Charge and discharge at +55 °C . 34
Table 24 – Trickle charge acceptance for JT cylindrical cells . 34
Table 25 – Constant discharge currents used for measurement of DC resistance . 36
Table 26 – Sequence of tests for type approval for small prismatic cells . 37
Table 27 – Sequence of tests for type approval for small prismatic cells (high recovery
type) . 38
Table 28 – Sequence of tests for type approval for button cells . 39
Table 29 – Sequence of tests for type approval for button cells (high recovery type) . 40
Table 30 – Sequence of tests for type approval for cylindrical cells . 41
Table 31 – Sequence of tests for type approval for cylindrical cells (high recovery
type) . 42
Table 32 – Sequence of tests for type approval for batteries . 43
Table 33 – Sequence of tests for type approval for batteries (high recovery type) . 43
Table 34 – Recommended test sequence for batch acceptance . 44

IEC 61951-2:2017 © IEC 2017 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
SECONDARY CELLS AND BATTERIES CONTAINING
ALKALINE OR OTHER NON-ACID ELECTROLYTES –
SECONDARY SEALED CELLS AND BATTERIES
FOR PORTABLE APPLICATIONS –
Part 2: Nickel-metal hydride
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.
International Standard IEC 61951-2 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.
This fourth edition cancels and replaces the third edition published in 2011 of which it
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
• addition of battery type;
• addition of ‘F’ (high recovery type) designation for cells and batteries;
• addition of ‘I’ (low self-discharge type) designation for cells;

– 6 – IEC 61951-2:2017 © IEC 2017
• revision of Figure 3 (6.1.3.1);
• addition of “optional pip” note to positive contact;
• changed leader line position from pip to flats of positive contact (B and G).
The text of this standard is based on the following documents:
FDIS Report on voting
21A/623/FDIS 21A/629/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 of the IEC 61951 series can be found, under the general title Secondary cells
and batteries containing alkaline or other non-acid electrolytes – Secondary sealed cells and
batteries for portable applications, 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.
IEC 61951-2:2017 © IEC 2017 – 7 –
SECONDARY CELLS AND BATTERIES CONTAINING
ALKALINE OR OTHER NON-ACID ELECTROLYTES –
SECONDARY SEALED CELLS AND BATTERIES
FOR PORTABLE APPLICATIONS –
Part 2: Nickel-metal hydride
1 Scope
This part of IEC 61951 specifies marking, designation, dimensions, tests and requirements for
secondary sealed nickel-metal hydride small prismatic, cylindrical and button cells and
batteries, suitable for use in any orientation, for portable applications.
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 60086-1, Primary batteries – Part 1: General
IEC 60086-2, Primary batteries – Part 2: Physical and electrical specifications
IEC 61959, Secondary cells and batteries containing alkaline or other non-acid electrolytes –
Mechanical tests for sealed portable secondary cells and batteries
IEC 62133-1, 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 1: Nickel systems
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 60050-482 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
nominal voltage
suitable approximate value of the voltage used to designate or identify a cell or a battery
Note 1 to entry: The nominal voltage of a sealed nickel-metal hydride rechargeable single cell is 1,2 V.
Note 2 to entry: The nominal voltage of a battery of n series connected cells is equal to n times the nominal
voltage of a single cell.
– 8 – IEC 61951-2:2017 © IEC 2017
[SOURCE: IEC 60050-482:2004, 482-03-31, modified – Addition of Notes 1 and 2 to entry.]
3.2
rated capacity
capacity value of a cell or battery determined under specified conditions and declared by the
manufacturer
Note 1 to entry: The rated capacity is the quantity of electricity C Ah (ampere-hours) declared by the
manufacturer which a single cell can deliver during a 5 h period when charging, storing and discharging under the
conditions specified in 7.3.2.
Note 2 to entry: The capacity of a battery is the quantity of electricity C Ah (ampere-hours) declared by the
manufacturer which a battery can deliver during a 5 h period, when charged, stored and discharged under the
procedure described in 7.3.2.
[SOURCE: IEC 60050-482:2004, 482-03-15, modified – Addition of Notes 1 and 2 to entry.]
3.3
small prismatic cell
cell in the form of a rectangular parallelepiped whose width and thickness dimensions are not
more than 25 mm
3.4
cylindrical cell
cell of circular cross-section in which the overall height is equal to, or greater than the overall
diameter
3.5
button cell
cell of circular cross-section in which the overall height is less than the overall diameter
3.6
nickel-metal hydride cell
cell containing a nickel hydroxide compound for the positive electrode, a hydrogen absorbing
alloy for the negative electrode, and potassium hydroxide or other alkaline solution as
electrolyte
Note 1 to entry: Positive electrodes are isolated from negative electrodes by a separator
3.7
nickel-metal hydride battery
assembly of secondary cell(s) as a source of electrical energy characterized by its voltage,
size, terminal arrangement, capacity and rate capability
3.8
sealed cell
cell which remains closed and does not release either gas or liquid when operated within the
limits of charge and temperature specified by the manufacturer
Note 1 to entry: The cell is equipped with a safety device to prevent dangerously high internal pressure.
Note 2 to entry: The cell does not require addition to the electrolyte and is designed to operate during its life in its
original sealed state.
Note 3 to entry: The nickel-metal hydride cell, however, may release gas towards the end of its life due to the
accumulation of hydrogen in the cell.
[SOURCE: IEC 60050-482:2004, 482-05-17, modified – The existing note has been developed
into Notes 1, 2 and 3 to entry.]

IEC 61951-2:2017 © IEC 2017 – 9 –
3.9
portable cell
cell designed mainly for use in an easily hand-carried battery
3.10
battery for portable applications
battery for use in device or appliance which is conveniently hand-carried
3.11
surface temperature limited cell
cell which performs a function that prevents the temperature increase from a certain standard
point even at the moment of an abnormal occurrence such as short circuit of cell
3.12
high recovery type cell or battery
cell or battery which has lower “permanent capacity loss” than normal type after storage
Note 1 to entry: It is defined as “high recovery type” in 7.10.2, Table 22.
3.13
low self-discharge type cell
cell which is able to retain higher charge capacity than normal type after storage by reducing
self-discharge
Note 1 to entry: It is defined as “low self-discharge type” in 7.4.
3.14
9 V type nickel-metal hydride battery
nickel-metal hydride battery which is interchangeable with 9 V primary batteries and is
composed of cylindrical cells, small prismatic cells or button cells
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;
g) ±5 % for humidity.
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 each report of results.

– 10 – IEC 61951-2:2017 © IEC 2017
5 Cell and battery designation and marking
5.1 Cell and battery designation
5.1.1 Small prismatic cells and cylindrical cells
5.1.1.1 General
Sealed nickel-metal hydride small prismatic rechargeable single cells and cylindrical
rechargeable single cells shall be designated by a letter L, M, J, H or X which signifies:
• low rate of discharge (L);
• medium rate of discharge (M);
• medium high rate of discharge (J);
• high rate of discharge (H);
• very high rate of discharge (X).
NOTE 1 These cells are typically but not exclusively used for the following discharge rates:
• L up to 0,5 I A;
t
• M up to 3,5 I A;
t
• J up to 5,0 I A;
t
• H up to 7,0 I A;
t
• X up to and above 7,0 I A.
t
NOTE 2 These currents are expressed as multiples of I A, where I A = C Ah/1 h (see IEC 61434).
t t 5
When a cell is intended for permanent charge at elevated temperatures, typically higher than
40 °C, a letter "T" is placed after the letter L, M, J, H or X.
When a cell is intended for permanent charge at elevated temperatures, typically higher than
50 °C, a letter "U" is placed after the letter L, M, J, H or X.
When a cell is intended for surface temperature limitation, a letter “S” is placed after the
letter L or M.
When a cell is intended for rapid charge, typically at 1,0 I A, a letter "R" is placed after the
t
letter L, M, J, H or X.
When a cell or battery is intended as a high recovery type, a letter “F” is placed after the letter
L, M, J, H or X.
When a cell is intended as a low self-discharge cell, a letter “I” is placed after the
letter L, M, J, H or X.
5.1.1.2 Small prismatic cells
Sealed nickel-metal hydride small prismatic rechargeable single cells shall be designated by
the letters "HF" followed by a letter L, M, J, H or X followed by letter F, followed by, if
designated, letter I, followed by three groups of figures, each group being separated by a
solidus, as follows:
a) The two figures to the left of the first solidus shall indicate the maximum width specified
for the cell, expressed in millimetres, rounded up to the next whole number.
b) The two figures in the middle shall indicate the maximum thickness specified for the cell,
expressed in millimetres, rounded up to the next whole number.

IEC 61951-2:2017 © IEC 2017 – 11 –
c) The two figures to the right of the second solidus shall indicate the maximum height
specified for the cell, expressed in millimetres, rounded up to the next whole number.
EXAMPLE HFLF 18/07/49 designation identifies a small prismatic cell of low discharge rate capability, high
recovery type with a maximum width of 18 mm, a maximum thickness of 7 mm and a maximum height of 49 mm.
5.1.1.3 Cylindrical cells
Sealed nickel-metal hydride cylindrical rechargeable single cells shall be designated by the
letters "HR" followed by a letter L, M, J, H or X followed by letter F, followed by, if designated,
letter I, followed by two groups of figures, each group being separated by a solidus, as
follows:
a) The two figures to the left of the solidus shall indicate the maximum diameter specified for
the cell, expressed in millimetres, rounded up to the next whole number.
b) The two figures to the right of the solidus shall indicate the maximum height specified for
the cell, expressed in millimetres, rounded up to the next whole number.
When a manufacturer designs a cell with dimensions and tolerances which make it
interchangeable with a primary cell, the designation of Table 2 shall also be marked on the
cell.
EXAMPLE 1 HRLF 33/62 designation identifies a cylindrical cell of low discharge rate capability, high recovery
type with a maximum diameter of 33 mm and a maximum height of 61,5 mm.
EXAMPLE 2 HRLTF 33/62 designation identifies a cylindrical cell of low discharge rate capability, intended for
permanent charge at elevated temperatures, high recovery type, with a maximum diameter of 33 mm and a
maximum height of 61,5 mm.
EXAMPLE 3 HRXRFI 23/43 designation identifies a cylindrical cell of very high discharge rate capability, intended
for rapid charge, high recovery type, low self-discharge type with a maximum diameter of 23 mm and a maximum
height of 43 mm.
For cells dimensionally interchangeable with primary cells, the following single or double
figures following the letter F or I may indicate:
• 20- Size D;
• 14- Size C;
• 6- Size AA;
• 03- Size AAA.
NOTE Cells dimensionally interchangeable with primary cells correspond to M type unless otherwise specified
For the purpose of this explanation, an example is given below.
EXAMPLE 4 HRMRFI03 designation identifies a sealed nickel-metal hydride cylindrical rechargeable single cell,
of medium discharge rate capability, also intended for rapid charge, high recovery type and low self-discharge
type, dimensionally interchangeable with primary cell and whose type designation is AAA.
5.1.2 Button cells
Sealed nickel-metal hydride button rechargeable single cells shall be designated by the letters
"HB" followed by letter F, followed by, if designated, letter I, followed by two groups of figures,
each group being separated by a solidus, as follows:
a) The three figures to the left of the solidus shall indicate the maximum diameter specified
for the cell, expressed in tenths of millimetres, rounded up to the next whole number.
b) The three figures to the right of the solidus shall indicate the maximum height specified for
the cell, expressed in tenths of millimetres, rounded up to the next whole number.
EXAMPLE HBFI 116/054 designation identifies a button cell, intended as a high recovery type, low self-discharge
type, with a maximum diameter of 11,6 mm and a maximum height of 5,4 mm.

– 12 – IEC 61951-2:2017 © IEC 2017
5.1.3 Batteries
Sealed nickel-metal hydride rechargeable batteries shall be designated with the following
form:
N1 single cell designation – N2
where
N1  is the number of series connected cells in the battery;
N2  is the number of parallel connected cells if 2 or greater (not shown if value is 1).
Sealed nickel-metal hydride battery designation will be identified based on single cells within
the series and not the battery as a whole.
• Small prismatic cells in battery
EXAMPLE 1 2HFLF 18/07/49 designation identifies a small prismatic cell of low discharge rate capability,
high recovery type with a maximum width of 18 mm, a maximum thickness of 7 mm and a maximum height of
49 mm with two series connected cells.
• Cylindrical cells in battery
EXAMPLE 2 3HRLF 33/62 designation identifies a cylindrical cell of low discharge rate capability, high
recovery type with a maximum diameter of 33 mm and a maximum height of 61,5 mm with three series
connected cells.
EXAMPLE 3 4HRLTF 33/62 designation identifies a cylindrical cell of low discharge rate capability, intended
for permanent charge at elevated temperatures, high recovery type, with a maximum diameter of 33 mm and a
maximum height of 61,5 mm with four series connected cells.
EXAMPLE 4 HRXRFI 23/43 -2 designation identifies a cylindrical cell of very high discharge rate capability,
intended for rapid charge, high recovery type, low self-discharge type with a maximum diameter of 23 mm and
a maximum height of 43 mm with two parallel connected cells.
• Cells interchangeable with primary cells in batteries
EXAMPLE 5 HRMRFI03-3 designation identifies a sealed nickel-metal hydride cylindrical rechargeable single
cell, of medium discharge rate capability, also intended for rapid charge, high recovery type and low self-
discharge type, dimensionally interchangeable with primary cell whose type designation is AAA with three
parallel connected cells.
• Button cells in battery
EXAMPLE 6 HB 116/054-3 designation identifies a button cell, with a maximum diameter of 11,6 mm and a
maximum height of 5,4 mm with three parallel connected cells.
5.2 Cell or battery termination
This standard does not specify cell or battery termination.
5.3 Marking
5.3.1 Small prismatic cells and cylindrical cells
Each jacketed cell supplied without connections shall carry durable markings giving the
following minimum information:
• sealed rechargeable nickel-metal hydride or Ni-MH;
• rated capacity;
• nominal voltage;
• polarity (+ and –);
• date of manufacture (which may be in code);
• name or identification of manufacturer or supplier;
• mark for promoting useful use of cell resources.
NOTE 1 This mark is applied where a recycling programme is available.

IEC 61951-2:2017 © IEC 2017 – 13 –
NOTE 2 In general, sealed nickel-metal hydride rechargeable single cells with connection tabs need no labels if
they form an integral part of a battery, in which case, the battery itself is marked with the above information.
5.3.2 Button cells
Each button cell supplied without connection shall carry durable markings giving the following
minimum information:
• designation as specified in 5.1;
• polarity (+ and –);
• date of manufacture (which may be in code);
• name or identification of manufacturer or supplier.
5.3.3 Batteries
Each battery shall carry durable markings giving the following minimum information:
• rated capacity;
• nominal voltage;
• date of manufacture (which may be in code).
5.4 Exemption of wording
Each cell or battery shall include minimum information on the label as specified in 5.3.1
to 5.3.3. Therefore, additional information such as safety cautions should be included in the
form of a manual not on the cell or battery label.
Each cell or battery shall include minimum information on the label as specified in 5.3.1 to
5.3.3. Therefore, cells or batteries encased in soft or hard plastic with the safety cautions
printed on the outside should not include caution details on the cell or battery label.
6 Dimensions
6.1 Small prismatic cells and cylindrical cells
6.1.1 General
Figures 1 and 2 show the shape of the cells.

– 14 – IEC 61951-2:2017 © IEC 2017
Diameter Thickness
Width
(+) (+)
(–)
(–)
IEC IEC
Figure 1 – Jacketed cylindrical cells Figure 2 – Jacketed small prismatic cells
6.1.2 Small prismatic cells
Table 1 shows the dimensions for jacketed small prismatic cells.
Table 1 – Dimensions of jacketed small prismatic cells
Cell designation Width Thickness Height
mm mm mm
HF 15/08/49 14,5 7,4 48,2
HF 15/09/49 14,5 8,3 48,2
HF 16/07/34 16,0 6,6 34,0 0
0 –1,0
HF 18/07/36 17,3 6,1 35,7
–0,7
HF 18/07/49 17,3 6,1 48,2
HF 18/09/49 17,3 8,3 48,2
–1,0
HF 18/07/68 17,3 6,1 67,3
HF 18/11/68 17,3 10,7 67,3
HF 18/18/68 17,3 17,3 67,3 0
–1,0
–1,5
HF 23/11/68 22,7 10,7 67,3
HF 23/15/68 22,7 14,5 67,3
6.1.3 Cylindrical cells
6.1.3.1 Cells dimensionally interchangeable with primary cells
Table 2 gives the requirements relative to the dimensions for jacketed cylindrical cells which
are dimensionally interchangeable with primary cells (see Figure 3).
Height
Height
IEC 61951-2:2017 © IEC 2017 – 15 –
Table 2 – Dimensions of jacketed cylindrical cells
dimensionally interchangeable with primary cells
Dimensions
mm
Type Nominal
Cell Corresponding
designation voltage
a c d
designation primary cell A B C D E
...