IEC 61951-2:2011

Secondary cells and batteries containing alkaline or other non-acid electrolytes - Portable sealed rechargeable single cells - Part 2: Nickel-metal hydride

IEC 61951-2:2011 specifies marking, designation, dimensions, tests and requirements for portable sealed nickel-metal hydride, small prismatic, cylindrical and button rechargeable single cells, suitable for use in any orientation. This third edition cancels and replaces the second edition published in 2003 of which it constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition:
- clause 4: addition of 2 parameters;
- clause 5: addition of cells type "S" and cells type "T";
- subclause 6.1.2: addition of new cylindrical cells;
- subclause 7.8: addition of a specific test for "S" cells.

Accumulateurs alcalins et autres accumulateurs à électrolyte non acide - Accumulateurs individuels portables étanches - Partie 2: Nickel-métal hydrure

La CEI 61951-2:2011 spécifie le marquage, la désignation, les dimensions, les essais et les exigences applicables aux petits éléments parallélépipédiques, aux éléments cylindriques et aux éléments boutons, individuels, portables, rechargeables, étanches, au nickel-métal hydrure, pouvant être utilisés dans toutes les orientations. Cette troisième édition annule et remplace la deuxième édition parue en 2003, dont elle constitue une révision technique. Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente:
- article 4: ajout de 2 paramètres;
- article 5: ajout d'éléments type "S" et éléments type "T";
- paragraphe 6.1.2: ajout de nouveaux éléments cylindriques;
- paragraphe 7.8: ajout d'un essai spécifique pour les éléments "S".

General Information

• Status: Published
• Publication Date: 24-May-2011
• ICS: 29.220.30 - Alkaline secondary cells and batteries
• Technical Committee: SC 21A - Secondary cells and batteries containing alkaline or other non-acid electrolytes
• Current Stage: DELPUB - Deleted Publication
• Completion Date: 22-Mar-2017

Relations

• Revised: IEC 61951-2:2017 - Secondary cells and batteries containing alkaline or other non acid electrolytes - Secondary sealed cells and batteries for portable applications - Part 2: Nickel-metal hydride
• Effective Date: 05-Sep-2023
• Revises: IEC 61951-2:2003 - Secondary cells and batteries containing alkaline or other non-acid electrolytes - Portable sealed rechargeable single cells - Part 2: Nickel-metal hydride
• Effective Date: 05-Sep-2023

Standards Content (Sample)

IEC 61951-2 ®
Edition 3.0 2011-05
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Secondary cells and batteries containing alkaline or other non-acid
electrolytes – Portable sealed rechargeable single cells –
Part 2: Nickel-metal hydride
Accumulateurs alcalins et autres accumulateurs à électrolyte non acide –
Accumulateurs individuels portables étanches –
Partie 2: Nickel-métal hydrure

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by
any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either IEC or
IEC's member National Committee in the country of the requester.
If you have any questions about IEC copyright or have an enquiry about obtaining additional rights to this publication,
please contact the address below or your local IEC member National Committee for further information.

Droits de reproduction réservés. Sauf indication contraire, aucune partie de cette publication ne peut être reproduite
ni utilisée sous quelque forme que ce soit et par aucun procédé, électronique ou mécanique, y compris la photocopie
et les microfilms, sans l'accord écrit de la CEI ou du Comité national de la CEI du pays du demandeur.
Si vous avez des questions sur le copyright de la CEI ou si vous désirez obtenir des droits supplémentaires sur cette
publication, utilisez les coordonnées ci-après ou contactez le Comité national de la CEI de votre pays de résidence.

IEC Central Office
3, rue de Varembé
CH-1211 Geneva 20
Switzerland
Email: [e-mail]
Web: www.iec.ch
About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.

About IEC publications
The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the
latest edition, a corrigenda or an amendment might have been published.
 Catalogue of IEC publications: www.iec.ch/searchpub
The IEC on-line Catalogue enables you to search by a variety of criteria (reference number, text, technical committee,…).
It also gives information on projects, withdrawn and replaced publications.
 IEC Just Published: www.iec.ch/online_news/justpub
Stay up to date on all new IEC publications. Just Published details twice a month all new publications released. Available
on-line and also by email.
 Electropedia: www.electropedia.org
The world's leading online dictionary of electronic and electrical terms containing more than 20 000 terms and definitions
in English and French, with equivalent terms in additional languages. Also known as the International Electrotechnical
Vocabulary online.
 Customer Service Centre: www.iec.ch/webstore/custserv
If you wish to give us your feedback on this publication or need further assistance, please visit the Customer Service
Centre FAQ or contact us:
Email: [e-mail]
Tel.: [phone]
Fax: [phone]
A propos de la CEI
La Commission Electrotechnique Internationale (CEI) est la première organisation mondiale qui élabore et publie des
normes internationales pour tout ce qui a trait à l'électricité, à l'électronique et aux technologies apparentées.

A propos des publications CEI
Le contenu technique des publications de la CEI est constamment revu. Veuillez vous assurer que vous possédez
l’édition la plus récente, un corrigendum ou amendement peut avoir été publié.
 Catalogue des publications de la CEI: www.iec.ch/searchpub/cur_fut-f.htm
Le Catalogue en-ligne de la CEI vous permet d’effectuer des recherches en utilisant différents critères (numéro de référence,
texte, comité d’études,…). Il donne aussi des informations sur les projets et les publications retirées ou remplacées.
 Just Published CEI: www.iec.ch/online_news/justpub
Restez informé sur les nouvelles publications de la CEI. Just Published détaille deux fois par mois les nouvelles
publications parues. Disponible en-ligne et aussi par email.
 Electropedia: www.electropedia.org
Le premier dictionnaire en ligne au monde de termes électroniques et électriques. Il contient plus de 20 000 termes et
définitions en anglais et en français, ainsi que les termes équivalents dans les langues additionnelles. Egalement appelé
Vocabulaire Electrotechnique International en ligne.
 Service Clients: www.iec.ch/webstore/custserv/custserv_entry-f.htm
Si vous désirez nous donner des commentaires sur cette publication ou si vous avez des questions, visitez le FAQ du
Service clients ou contactez-nous:
Email: [e-mail]
Tél.: [phone]
Fax: [phone]
IEC 61951-2 ®
Edition 3.0 2011-05
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Secondary cells and batteries containing alkaline or other non-acid
electrolytes – Portable sealed rechargeable single cells –
Part 2: Nickel-metal hydride
Accumulateurs alcalins et autres accumulateurs à électrolyte non acide –
Accumulateurs individuels portables étanches –
Partie 2: Nickel-métal hydrure

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX V
ICS 29.220.30 ISBN 978-2-88912-497-8

– 2 – 61951-2 © IEC:2011
CONTENTS
FOREWORD . 4
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
4 Parameter measurement tolerances . 7
5 Cell designation and marking. 8
5.1 Cell designation . 8
5.1.1 Small prismatic cells and cylindrical cells . 8
5.1.2 Button cells . 9
5.2 Cell termination . 9
5.3 Marking . 9
5.3.1 Small prismatic cells and cylindrical cells . 9
5.3.2 Button cells . 10
6 Dimensions . 10
6.1 Small prismatic cells and cylindrical cells . 10
6.1.1 General . 10
6.1.2 Small prismatic cells . 11
6.1.3 Cylindrical cells . 12
6.2 Button cells . 14
7 Electrical tests . 14
7.1 General . 14
7.2 Charging procedure for test purposes . 14
7.3 Discharge performance . 15
7.3.1 General . 15
7.3.2 Discharge performance at 20 °C . 15
7.3.3 Discharge performance at 0 °C . 15
7.3.4 Discharge performance for rapid charge cells (R cells) . 16
7.4 Charge (capacity) retention . 16
7.5 Endurance . 17
7.5.1 Endurance in cycles . 17
7.5.2 Permanent charge endurance . 19
7.6 Charge acceptance at constant voltage . 23
7.7 Overcharge . 23
7.7.1 Small prismatic, L, M, H, X, LS or MS cylindrical, and button cells . 23
7.7.2 LT/LU, MT/MU or HT/HU cylindrical cells . 23
7.7.3 R cylindrical cells. 23
7.8 Safety device operation . 24
7.9 Surface temperature limitation device operation (for S cell only) . 24
7.10 Storage . 25
7.11 Charge acceptance at +55 °C for LT, MT or HT cylindrical cells . 25
7.12 Internal resistance . 26
7.12.1 General . 26
7.12.2 Measurement of the internal a.c. resistance . 26
7.12.3 Measurement of the internal d.c. resistance . 27
8 Mechanical tests. 27

61951-2 © IEC:2011 – 3 –
9 Safety requirements . 27
10 Type approval and batch acceptance. 27
10.1 Type approval . 27
10.1.1 Type approval for small prismatic cells and button cells . 27
10.1.2 Type approval for cylindrical cells . 28
10.2 Batch acceptance . 29
Bibliography . 31

Figure 1 – Jacketed cylindrical cells . 11
Figure 2 – Jacketed small prismatic cells . 11
Figure 3 – Jacketed cells dimensionally interchangeable with primary cells . 12
Figure 4 – Button cells . 14

Table 1 – Dimensions of jacketed small prismatic cells . 11
Table 2 – Jacketed cylindrical cells dimensionally interchangeable with primary cells . 12
Table 3 – Jacketed cylindrical cells not dimensionally interchangeable with primary
cells . 13
Table 4 – Dimensions of button cells . 14
Table 5 – Discharge performance at 20 °C for small prismatic cells and cylindrical cells . 15
Table 6 – Discharge performance at 20 °C for button cells . 15
Table 7 – Discharge performance at 0 °C for small prismatic cells and cylindrical cells . 16
Table 8 – Discharge performance at 0 °C for button cells . 16
Table 9 – Endurance in cycles for small prismatic, button and cylindrical cells not
dimensionally interchangeable with primary cells . 17
Table 10 – Endurance in cycles for H or X cells . 18
Table 11 – Endurance in cycles for X cells . 18
Table 12 – Endurance in cycles for HR or XR cells . 19
Table 13 – Permanent charge endurance for L, M, H or X cells . 19
Table 14 – Permanent charge endurance for LT, MT or HT cells . 21
Table 15 – Permanent charge endurance for LU, MU or HU cells . 22
Table 16 – Overcharge at 0 °C . 23
Table 17 – Charge and discharge at +55 °C . 26
Table 18 – Constant discharge currents used for measurement of d.c. resistance . 27
Table 19 – Sequence of tests for type approval for small prismatic and for button cells . 28
Table 20 – Sequence of tests for type approval for cylindrical c
...