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

IEC 61951-2:2017 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.
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;
- 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).

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

L'IEC 61951-2:2017 spécifie le marquage, la désignation, les dimensions, les essais et les exigences applicables aux éléments et batteries d’accumulateurs parallélépipédiques, cylindriques et boutons, étanches, au nickel-métal hydrure, pouvant être utilisés dans toutes les orientations, pour applications portables.
Cette édition inclut les modifications techniques majeures suivantes par rapport à l’édition précédente:
- ajout du type de batterie;
- ajout de la désignation ‘F’ (type à récupération élevée) pour les éléments et batteries;
- ajout de la désignation ‘I’ (type à autodécharge faible) pour les éléments;
- révision de la Figure 3 (6.1.3.1);
- ajout de la note "picot facultatif" au contact positif;
- modification de la position de la ligne de repère du picot aux surfaces planes du contact positif (B et G).

General Information

• Status: Published
• Publication Date: 21-Mar-2017
• ICS: 01 - GENERALITIES. TERMINOLOGY. STANDARDIZATION. DOCUMENTATION
• ICS: 29.220.30 - Alkaline secondary cells and batteries
• Technical Committee: SC 21A - Secondary cells and batteries containing alkaline or other non-acid electrolytes
• Drafting Committee: WG 2 - TC 21/SC 21A/WG 2
• Current Stage: PPUB - Publication issued
• Start Date: 10-Mar-2017
• Completion Date: 22-Mar-2017

Relations

• Amended By: IEC 61951-2:2017/AMD1:2022 - Amendment 1 - 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 61951-2:2011 - 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 4.0 2017-03
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
inside
Secondary cells and batteries containing alkaline or other non-acid
electrolytes – Portable sealed rechargeable single cells Secondary sealed cells
and batteries for portable applications –
Part 2: Nickel-metal hydride
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.

IEC Central Office Tel.: [phone]
3, rue de Varembé Fax: [phone]
CH-1211 Geneva 20 [e-mail]
Switzerland 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.

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IEC 61951-2 ®
Edition 4.0 2017-03
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
inside
Secondary cells and batteries containing alkaline or other non-acid

electrolytes – Portable sealed rechargeable single cells Secondary sealed cells

and batteries for portable applications –

Part 2: Nickel-metal hydride
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.220.30 ISBN 978-2-8322-4140-0

– 2 – IEC 61951-2:2017 RLV © 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 . 29
7.7 Overcharge . 29
7.7.1 Small prismatic, L, M, H, X, LS or MS cylindrical, and button cells . 29
7.7.2 LT/LU, MT/MU or HT/HU cylindrical cells . 30
7.7.3 J cylindrical cells . 30
7.7.4 JT cylindrical cells . 30
7.7.5 R cylindrical cells . 31
7.8 Safety device operation . 31
7.9 Surface temperature limitation device operation (for S cell only) . 31

7.10 Storage . 32
7.10.1 Button cells or batteries, small prismatic cells or batteries, cylindrical
cells or batteries . 32
7.10.2 Button cells or batteries, small prismatic cells or batteries, cylindrical
cells or batteries (high recovery type) . 33
7.11 Charge acceptance at +55 °C for LT, MT or HT cylindrical cells . 34
7.12 Trickle charge acceptance for JT cylindrical cells . 35
7.13 Internal resistance . 35
7.13.1 General . 35
7.13.2 Measurement of the internal AC resistance . 36
7.13.3 Measurement of the internal DC resistance . 36
8 Mechanical tests . 37
9 Safety requirements . 37
10 Type approval and batch acceptance . 37
10.1 General . 37
10.2 Type approval . 37
10.2.1 Type approval for small prismatic cells and button cells . 37
10.2.2 Type approval for cylindrical cells . 41
10.2.3 Type approval for batteries . 43
10.3 Batch acceptance . 44
Bibliography . 46

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 RLV © IEC 2017
Table 16 – Endurance in cycles for cylindrical cells dimensionally interchangeable with
primary cells .
...

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

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 l'IEC ou du Comité national de l'IEC du pays du demandeur. Si vous avez des
questions sur le copyright de l'IEC ou si vous désirez obtenir des droits supplémentaires sur cette publication, utilisez
les coordonnées ci-après ou contactez le Comité national de l'IEC de votre pays de résidence.

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Switzerland 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
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latest edition, a corrigenda or an amendment might have been published.

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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

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 .
...

IEC 61951-2 ®
Edition 4.1 2022-10
CONSOLIDATED VERSION
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
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

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 l'IEC ou du Comité national de l'IEC du pays du demandeur. Si vous avez des
questions sur le copyright de l'IEC ou si vous désirez obtenir des droits supplémentaires sur cette publication, utilisez
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About the IEC
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International Standards for all electrical, electronic and related technologies.

About IEC publications
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IEC 61951-2 ®
Edition 4.1 2022-10
CONSOLIDATED VERSION
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
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 978-2-8322-6002-9

IEC 61951-2 ®
Edition 4.1 2022-10
CONSOLIDATED VERSION
REDLINE VERSION
VERSION REDLINE
colour
inside
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

– 2 – IEC 61951-2:2017+AMD1:2022 CSV
© IEC 2022
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 . 17
6.3 9 V type nickel-metal hydride batteries . 18
7 Electrical tests . 19
7.1 General . 19
7.2 Charging procedure for test purposes . 19
7.2.1 Charging procedure for cell. 19
7.2.2 Charging procedure for battery . 19
7.3 Discharge performance . 19
7.3.1 General . 19
7.3.2 Discharge performance at 20 °C . 20
7.3.3 Discharge performance at 0 °C . 21
7.3.4 Discharge performance for rapid charge cells (R cells) . 22
7.4 Charge (capacity) retention . 22
7.5 Endurance . 23
7.5.1 Endurance in cycles. 23
7.5.2 Permanent charge endurance . 26
7.6 Charge acceptance at constant voltage . 29
7.7 Overcharge . 29
7.7.1 Small prismatic, L, M, H, X, LS or MS cylindrical, and button cells . 29
7.7.2 LT/LU, MT/MU or HT/HU cylindrical cells . 30
7.7.3 J cylindrical cells . 30
7.7.4 JT cylindrical cells . 30
7.7.5 R cylindrical cells . 31
7.8 Safety device operation Pressure relief feature . 31
7.9 Surface temperature limitation device operation (for S cell only) . 31

© IEC 2022
7.10 Storage . 32
7.10.1 Button cells or batteries, small prismatic cells or batteries, cylindrical
cells or batteries . 32
7.10.2 Button cells or batteries, small prismatic cells or batteries, cylindrical
cells or batteries (high recovery type) . 33
7.11 Charge acceptance at +55 °C for LT, MT or HT cylindrical cells . 34
7.12 Trickle charge acceptance for JT cylindrical cells . 35
7.13 Internal resistance . 35
7.13.1 General . 35
7.13.2 Measurement of the internal AC resistance . 36
7.13.3 Measurement of the internal DC resistance . 36
8 Mechanical tests . 37
9 Safety requirements . 37
10 Type approval and batch acceptance . 37
10.1 General . 37
10.2 Type approval . 37
10.2.1 Type approval for small prismatic cells and button cells . 37
10.2.2 Type approval for cylindrical cells . 41
10.2.3 Type approval for batteries . 43
10.3 Batch acceptance . 44
Bibliography . 46

Figure 1 – Jacketed cylindrical c
...