ISO 7176-31:2023

DRAFT INTERNATIONAL STANDARD
ISO/DIS 7176-31
ISO/TC 173/SC 1 Secretariat: SABS
Voting begins on: Voting terminates on:
2022-07-04 2022-09-26
Wheelchairs —
Part 31:
Lithium-ion battery systems and chargers for powered
wheelchairs – Requirements and test methods
ICS: 11.180.10
THIS DOCUMENT IS A DRAFT CIRCULATED
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ISO/DIS 7176-31:2022(E)
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PROVIDE SUPPORTING DOCUMENTATION. © ISO 2022

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ISO/DIS 7176-31:2022(E)
DRAFT INTERNATIONAL STANDARD
ISO/DIS 7176-31
ISO/TC 173/SC 1 Secretariat: SABS
Voting begins on: Voting terminates on:

Wheelchairs —
Part 31:
Lithium-ion battery systems and chargers for powered
wheelchairs – Requirements and test methods
ICS: 11.180.10
COPYRIGHT PROTECTED DOCUMENT
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENT AND APPROVAL. IT IS
© ISO 2022
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NATIONAL REGULATIONS.
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ii
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PROVIDE SUPPORTING DOCUMENTATION. © ISO 2022

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ISO/DIS 7176-31:2022(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Lithium Batteries . 4
4.1 Battery performance and safety requirements . 4
4.1.1 General . 4
4.1.2 Internal short-circuit within a cell . 4
4.1.3 Battery cyclic endurance . 4
4.1.4 Thermal runaway . 4
4.1.5 Transport and storage . 4
4.2 Requirements for battery management systems . 5
4.2.1 General . 5
4.2.2 Functional requirements . 5
4.2.3 EMC requirements . 6
4.2.4 Environmental protection requirements . 6
5 Requirements for the battery charging system . 6
5.1 Charger connector . 6
5.1.1 General . 6
5.1.2 XLR battery charger connector . 6
5.1.3 XLR wheelchair charger connector . 6
5.2 Battery charger function . 7
5.2.1 Requirements . 7
6 User manuals .11
6.1 Charger connector . 11
6.2 Battery user manual . 11
7 Battery labelling.11
8 Requirements for information disclosure .12
9 Test report .12
Annex A (informative) .13
Bibliography .14
iii
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ISO/DIS 7176-31:2022(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to
the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see
www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 173, Assistive products for persons with
disability, Subcommittee SC 1, Wheelchairs.
A list of all parts in the ISO 7176 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
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ISO/DIS 7176-31:2022(E)
Introduction
This version of ISO 7176-31 was developed to standardize requirements for use of Lithium-ion
batteries in wheelchairs. Lithium chemistries in their various derivatives are becoming more common
in wheelchairs so it is now appropriate to standardize performance and safety requirements for this
application. Additionally, a number of national and international standards have been published that
define the safety and performance of lithium batteries in more general applications. These standards
form the basis for this document.
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DRAFT INTERNATIONAL STANDARD ISO/DIS 7176-31:2022(E)
Wheelchairs —
Part 31:
Lithium-ion battery systems and chargers for powered
wheelchairs – Requirements and test methods
WARNING — The use of this part of ISO 7176 can involve hazardous materials, operations
and equipment. It does not purport to address all of the safety or environmental problems
associated with its use. It is the responsibility of users of this standard to take appropriate
measures to ensure the safety and health of personnel and the environment prior to application
of the standard. Particular care should be taken regarding the possible emission of toxic fumes
resulting from lithium battery fires.
1 Scope
This part of ISO 7176 specifies requirements and test methods for lithium batteries and battery systems
intended for use in electrically powered wheelchairs, and their charging systems.
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.
ISO 7176-25, Wheelchairs — Part 25: Batteries and chargers for powered wheelchairs
ISO 7176-2, Wheelchairs — Part 2: Determination of dynamic stability of electrically powered wheelchairs
ISO 7176-3, Wheelchairs — Part 3: Determination of effectiveness of brakes
ISO 7176-8, Wheelchairs — Part 8: Requirements and test methods for static, impact and fatigue strengths
ISO 7176-9, Wheelchairs — Part 9: Climatic tests for electric wheelchairs
ISO 7176-14, Wheelchairs — Part 14: Power and control systems for electrically powered wheelchairs and
scooters — Requirements and test methods
ISO 7176-15, Wheelchairs — Part 15: Requirements for information disclosure, documentation and labelling
ISO 7176-21, Wheelchairs — Part 21: Requirements and test methods for electromagnetic compatibility of
electrically powered wheelchairs and scooters, and battery chargers
IEC 60335-2-29:2016, +Amd1: 2019, Household and similar electrical appliances — Safety — Part 2-29:
Particular requirements for battery chargers
IEC 60529, Degrees of protection provided by enclosures (IP Code)
IEC 62133-2, Secondary cells and batteries containing alkaline or other non-acid electrolytes - Safety
requirements for portable sealed secondary lithium cells, and for batteries made from them, for use in
portable applications - Part 2: Lithium systems
IEC 61960-3, Secondary cells and batteries containing alkaline or other non-acid electrolytes - Secondary
lithium cells and batteries for portable applications - Part 3: Prismatic and cylindrical lithium secondary
cells and batteries made from them
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ISO/DIS 7176-31:2022(E)
IEC 62619, Secondary cells and batteries containing alkaline or other non-acid electrolytes - Safety
requirements for secondary lithium cells and batteries, for use in industrial applications
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
battery cell
cell
basic manufactured unit providing a source of electrical energy by direct conversion of chemical energy,
that consists of electrodes, separators, electrolyte, container and terminals, and that is designed to be
charged electrically
[SOURCE: IEC 62133-2, 3.7]
3.2
battery pack
pack
energy storage device, which is comprised of one or more cells or modules electrically connected
Note 1 to entry: Some battery management functions are, by necessity, integrated into the battery; others may
need to be integrated into the control and drive system.
Note 2 to entry: It may incorporate a protective housing and be provided with terminals or other interconnection
arrangement.
[SOURCE: IEC 62619, 3.10 modified]
3.3
battery module
module
group of cells connected together either in a series and/or parallel configuration with or without
protective devices (e.g. fuse or PTC) and monitoring circuitry
[SOURCE: IEC 62133-2, 3.9 modified]
3.4
lithium ion battery
secondary battery with an organic solvent electrolyte and positive and negative electrodes which
utilize an intercalation compound in which lithium is stored
Note 1 to entry: A lithium ion battery does not contain lithium metal.
[SOURCE: IEV 482-05-07 modified]
3.5
battery management system
BMS
electronic system associated with a battery which has functions to maintain safety and prevent damage
such as protection from over-charge, over-discharge, over-current, over-heating, and cell imbalance.
Note 1 to entry: It monitors and/or manages its state, calculates secondary data, reports that data and/or
controls its environment to influence the battery’s safety, performance and/or service life.
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ISO/DIS 7176-31:2022(E)
Note 2 to entry: The function of the BMS can be assigned to the battery pack or to wheelchair that uses the
battery. (See Figure 1)
Note 3 to entry: The BMS can be divided and it can be found partially in the battery (pack) and partially on the
wheelchair that uses the battery.
3.6
battery system
battery
system which comprises one or more cells, modules or battery packs
Note 1 to entry: It has a battery management system (BMS) to cut off in case of over-charge, over-current, over-
discharge, over-heating and cell imbalance
Note 2 to entry: The battery system can have cooling or heating units.
[SOURCE: IEC 62619, 3.11 modified]
3.7
capacity
C
capacity expressed in ampere-hours (Ah)
3.8
rated capacity
capacity value of a cell or battery determined under specified conditions and declared by the
manufacturer
Note 1 to entry: Note to entry: The rated capacity is the quantity of electricity C5 Ah (ampere-hours) declared
by the manufacturer which a single cell can deliver when discharged at the reference test current of 0,2 It A to a
specified final voltage, after charging, storing and discharging under specified conditions.
3.9
Energy storage capacity
Watt hour rating
energy storage capacity expressed in watt hours (Wh)
[SOURCE: IEC 62619, 3.21]
3.10
Battery management system
BMS
emission of flames from a cell, module, battery pack, or battery system
[SOURCE: IEC 62619, 3.17]
3.11
battery charging system
Battery charger, battery system and interconnecting components in the charging circuit, including
connectors and protective devices.
Note 1 to entry: Note to entry: Parts of the battery charging system can be in the wheelchair.
3.12
safety extra-low voltage
voltage not exceeding 42 V between conductors and between conductors and earth, the no-load voltage
not exceeding 50 V
Note 1 to entry: When safety extra-low voltage is obtained from the supply mains, it is to be through a safety
isolating transformer or a convertor with separate windings, the insulation of which complies with double
insulation or reinforced insulation requirements.
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ISO/DIS 7176-31:2022(E)
Note 2 to entry: The voltage limits specified are based on the assume that the safety isolating transformer is
supplied at its rated voltage.
Note 3 to entry: Safety extra-low voltage is also known as SELV.
[SOURCE: IEC 60335-1:2020, 3.4.2]
3.13
safety isolating transformer
transformer, the input winding of which is electrically separated from the output winding by an
insulation at least equivalent to double insulation or reinforced insulation, that is intended to supply a
battery charging circuit having an output voltage not exceeding 120 V ripple-free direct current
Note 1 to entry: Note to entry: Ripple-free means an r.m.s. ripple voltage not exceeding 10 % of the DC compon
...