IEC 62932-2-2:2020
(Main)Flow battery energy systems for stationary applications - Part 2-2: Safety requirements
Flow battery energy systems for stationary applications - Part 2-2: Safety requirements
IEC 62932-2-2:2020 applies to flow battery systems for stationary applications and their installations with a maximum voltage not exceeding 1 500 V DC in compliance with IEC 62932-1. This document defines the requirements and test methods for risk reduction and protection measures against significant hazards relevant to flow battery systems, to persons, property and the environment, or to a combination of them. This document is applicable to stationary flow battery systems intended for indoor and outdoor commercial and industrial use in non-hazardous (unclassified) areas. This document covers significant hazards, hazardous situations and events, with the exception of those associated with natural disaster, relevant to flow battery systems, when they are used as intended and under the conditions foreseen by the manufacturer including reasonably foreseeable misuse thereof. The requirements described in this document are not intended to constrain innovations. When considering fluids, materials, designs or constructions not specifically dealt with in this document, these alternatives are evaluated as to their ability to yield levels of safety equivalent to those specified in this document.
Systèmes de production d'énergie à batteries d'accumulateurs à circulation d'électrolyte pour les applications stationnaires - Partie 2-2: Exigences de sécurité
L’IEC 62932-2-2:2020 s’applique aux systèmes de batteries d’accumulateurs à circulation d’électrolyte pour les applications stationnaires et à leurs installations avec une tension maximale ne dépassant pas 1 500 V en courant continu conformément à l’IEC 62932-1.
Le présent document définit les exigences et les méthodes d’essai pour la réduction du risque, ainsi que les mesures de protection contre les dangers significatifs, concernant les systèmes de batteries d’accumulateurs à circulation d’électrolyte, les personnes, les biens et l’environnement, ou une combinaison de ces facteurs.
Le présent document est applicable aux systèmes de batteries d’accumulateurs à circulation d’électrolyte stationnaires destinés à une utilisation commerciale et industrielle à l’intérieur et à l’extérieur dans des emplacements (non classés) non dangereux.
Le présent document couvre les dangers, ainsi que les situations et événements dangereux significatifs, à l’exception de ceux associés à une catastrophe naturelle, concernant les systèmes de batteries d’accumulateurs à circulation d’électrolyte, lorsqu’ils sont utilisés tel que prévu et dans les conditions prévues par le fabricant, y compris leur mauvaise utilisation raisonnablement prévisible.
Les exigences décrites dans le présent document ne sont pas destinées à limiter les innovations. La prise en compte des fluides, matériaux, conceptions ou constructions dont le présent document ne traite pas particulièrement évalue ces variantes quant à leur capacité à produire des niveaux de sécurité équivalant à ceux spécifiés dans le présent document.
General Information
Standards Content (Sample)
IEC 62932-2-2 ®
Edition 1.0 2020-02
INTERNATIONAL
STANDARD
Flow battery energy systems for stationary applications –
Part 2-2: Safety requirements
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IEC 62932-2-2 ®
Edition 1.0 2020-02
INTERNATIONAL
STANDARD
Flow battery energy systems for stationary applications –
Part 2-2: Safety requirements
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.220.99 ISBN 978-2-8322-7854-3
– 2 – IEC 62932-2-2:2020 © IEC 2020
CONTENTS
FOREWORD . 5
INTRODUCTION . 7
1 Scope . 8
2 Normative references . 8
3 Terms, definitions and abbreviated terms . 9
3.1 Terms and definitions . 9
3.2 Abbreviated terms . 9
4 Procedure of the risk analysis . 9
5 Safety requirements and protective measures . 10
5.1 General . 10
5.2 Risk information . 10
5.3 Electrical hazards . 10
5.3.1 Electrical shock . 10
5.3.2 Short-circuits . 10
5.3.3 Leakage currents . 11
5.4 Hazards of gaseous emissions . 11
5.4.1 General . 11
5.4.2 Harmful gas . 12
5.4.3 Ventilation . 13
5.4.4 Warning sign . 13
5.4.5 Close vicinity to emissions . 14
5.5 Hazard posed by liquids . 14
5.5.1 General . 14
5.5.2 Detection of electrolyte leakage . 14
5.5.3 Protective measures against leakage . 14
5.5.4 Specific information . 14
5.5.5 Flow path identification . 15
5.6 Hazards of mechanical cause . 15
5.7 Operational hazards and measures . 15
5.7.1 General . 15
5.7.2 Start . 15
5.7.3 Remote monitoring and control systems . 16
5.7.4 Protection . 16
5.7.5 Auxiliary power failure . 16
6 Instructions . 16
7 Identification labels or marking . 16
7.1 Name plate information . 16
7.2 Warning label information and location . 17
8 Transport, storage, disposal and environmental aspects . 17
8.1 Packing and transport . 17
8.2 Dismantling, disposal, and recycling . 17
9 Inspection . 17
10 Maintenance . 18
11 Verification tests for protective measures . 18
11.1 General . 18
11.1.1 Tests . 18
11.1.2 Test object . 19
11.1.3 Test category . 19
11.2 Dielectric strength of the parts in contact with the fluid . 19
11.2.1 Requirements . 19
11.2.2 Category . 19
11.2.3 Number of samples . 19
11.2.4 Test and acceptance criteria . 19
11.3 Operational sequence . 19
11.3.1 Requirements . 19
11.3.2 Category . 19
11.3.3 Number of samples . 19
11.3.4 Test . 20
11.3.5 Acceptance criteria . 20
11.4 Emergency stop . 20
11.4.1 Requirement . 20
11.4.2 Category . 20
11.4.3 Number of samples . 20
11.4.4 Test . 20
11.4.5 Acceptance criteria . 20
11.5 Protection . 20
11.5.1 Requirements . 20
11.5.2 Category . 21
11.5.3 Number of samples . 21
11.5.4 Test . 21
11.5.5 Acceptance criteria . 21
11.6 Safety requirement for stacks . 21
Annex A (informative) Recommended structure of user manual . 22
A.1 General . 22
A.2 Table of contents . 22
A.3 Safety warning . 22
A.4 Introduction . 22
A.5 Product description . 22
A.5.1 Overview . 22
A.5.2 Technical specifications . 23
A.5.3 System structure. 23
A.5.4 Applications . 23
A.5.5 Operational sequence . 23
A.6 Site requirements . 23
A.6.1 Location and load . 23
A.6.2 Access and clearance . 23
A.6.3 Precautionary measures for fluid containment. 23
A.6.4 Ventilation . 24
A.6.5 Temperature . 24
A.7 Operation . 24
A.7.1 General . 24
A.7.2 Checks before operation . 24
A.7.3 Energizing and de-energizing the system . 24
– 4 – IEC 62932-2-2:2020 © IEC 2020
A.7.4 Valve status . 24
A.7.5 Specific operations . 24
A.7.6 Notices for operation . 24
A.8 Alarms and fault finding . 25
A.9 Maintenance . 25
A.10 Contact information . 25
Annex B (normative) Safety requirements for stacks . 26
B.1 General . 26
B.2 External short-circuit of the stack . 26
B.2.1 Requirements . 26
B.2.2 Category . 26
B.2.3 Number of samples . 26
B.2.4 Test . 26
B.2.5 Acceptance criteria . 26
B.3 Heat shock strength . 27
B.3.1 Requirements . 27
B.3.2 Category . 27
B.3.3 Number of samples . 27
B.3.4 Test . 27
B.3.5 Acceptance criteria . 27
B.4 Leakage of the stack . 27
B.4.1 Requirements . 27
B.4.2 Category . 28
B.4.3 Number of samples . 28
B.4.4 Test . 28
B.4.5 Acceptance criteria . 28
Bibliography . 29
Figure 1 – Flow battery energy system . 7
Table 1 – List of verification tests for protective measurements . 18
Table B.1 – List of verification tests for stacks for protective measurements . 26
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
FLOW BATTERY ENERGY SYSTEMS FOR STATIONARY APPLICATIONS –
Part 2-2: Safety requirements
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
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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 edition.
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 62932-2-2 has been prepared by IEC technical committee 21:
Secondary cells and batteries, in collaboration with IEC technical committee 105: Fuel cell
technologies.
The text of this International Standard is based on the following documents:
FDIS Report on voting
21/1029/FDIS 21/1035/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.
A list of all parts in the IEC 62932 series, published under the general title Flow battery energy
systems for stationary applications, can be found on the IEC website.
– 6 – IEC 62932-2-2:2020 © IEC 2020
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.
INTRODUCTION
A flow battery system (FBS) can be utilized in a flow battery energy system (FBES). Such an
FBES can consist of:
– a flow battery system,
– a power conversion system,
– other equipment and surroundings.
The FBES is connected to the external power input/output via a point of connection (POC).
This document covers the domain of the FBES, as shown in Figure 1. Energy to the auxiliary
systems such as the battery management system (BMS), the battery support system (BSS),
and the power conversion system (PCS) may be supplied by one of the following:
a) direct connection to the external power source;
b) the internal power source of the FBES or FBS itself.
Figure 1 – Flow battery energy system
– 8 – IEC 62932-2-2:2020 © IEC 2020
FLOW BATTERY ENERGY SYSTEMS FOR STATIONARY APPLICATIONS –
Part 2-2: Safety requirements
1 Scope
This part of IEC 62932 applies to flow battery systems for stationary applications and their
installations with a maximum voltage not exceeding 1 500 V DC in compliance with
IEC 62932-1.
This document defines the requirements and test methods for risk reduction and protection
measures against significant hazards relevant to flow battery systems, to persons, property and
the environment, or to a combination of them.
This document is applicable to stationary flow battery systems intended for indoor and outdoor
commercial and industrial use in non-hazardous (unclassified) areas.
This document covers significant hazards, hazardous situations and events, with the exception
of those associated with natural disaster, relevant to flow battery systems, when they are used
as intended and under the conditions foreseen by the manufacturer including reasonably
foreseeable misuse thereof.
The requirements described in this document are not intended to constrain innovations. When
considering fluids, materials, designs or constructions not specifically dealt with in this
document, these alternatives are evaluated as to their ability to yield levels of safety equivalent
to those specified in this document.
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 60079-10-1, Explosive atmospheres – Part 10-1: Classification of areas – Explosive gas
atmospheres
IEC 60364-4-41, Low-voltage electrical installations – Part 4-41: Protection for safety –
Protection against electric shock
IEC 60364-4-43, Low-voltage electrical installations – Part 4-43: Protection for safety –
Protection against overcurrent
IEC 60364-6, Low voltage electrical installations – Part 6: Verification
IEC 61936-1, Power installations exceeding 1 kV a.c. – Part 1: Common rules
IEC 62485-2:2010, Safety requirements for secondary batteries and battery installations –
Part 2: Stationary batteries
IEC 62932-1, Flow battery energy systems for stationary applications – Part 1: Terminology and
general aspects
ISO 7010, Graphical symbols – Safety colours and safety signs – Registered safety signs
3 Terms, definitions and abbreviated terms
3.1 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 62932-1 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
3.2 Abbreviated terms
BMS battery management system
BSS battery support system
EES electrical energy storage
FBES flow battery energy system
FBS flow battery system
FMEA failure mode and effects analysis
FTA fault tree analysis
GHS global harmonized system
HAZOP hazard and operability study
MSDS material safety data sheet
PCS power conversion system
POC point of connection
SDS safety data sheet
UPS uninterruptible power system
4 Procedure of the risk analysis
A written risk analysis shall be performed on an FBES to ensure that:
a) all reasonably foreseeable hazards and hazardous events, including reasonably
foreseeable misuse throughout the anticipated lifetime, have been identified;
b) the risk for each of these hazards has been estimated from the combination of its probability
of occurrence and of its foreseeable severity;
c) the two factors which determine each one of the estimated risks (probability and severity)
have been eliminated or reduced to a level not exceeding the acceptable risk level as far
as reasonably possible according to the following principles in the order given:
– eliminate hazards or reduce risks by inherent design measures,
– take necessary protective measures in relation to risks that cannot be reduced by
inherent design measures,
– inform intended users and where appropriate other persons of the residual risks, indicate
whether any particular training is required and specify any need to use personal
protective equipment.
For example, failure mode and effects analysis (FMEA), fault tree analysis (FTA) methods,
hazard and operability study (HAZOP), and/or the following International Standards shall be
used as guidance:
• IEC 60812;
• IEC 61025.
– 10 – IEC 62932-2-2:2020 © IEC 2020
5 Safety requirements and protective measures
5.1 General
Each secondary battery has a different structure and therefore only the features critical or
specific to the flow battery shall be taken into consideration. The flow battery energy system as
shown in Figure 1 differs from other secondary batteries, in that a system for circulating the
electrolyte is present. The fluid circulating system consists of tanks, pumps, piping, sensors
and some safety-relevant devices.
From a chemical safety point of view, since fluid is contained in tanks, pipes and stacks, the
sealing is an important factor. There is also the possibility of hazardous gases being present,
requiring that appropriate countermeasures be implemented.
Clause 5 specifies the safety requirements and protective measures in consideration of the
above-mentioned aspects.
5.2 Risk information
The manufacturer shall provide the user with risk information based on the risk analysis to
describe hazards and the appropriate measures taken or to be taken for mitigation purposes.
The information shall include a safety data sheet (SDS).
The information can be provided in the form of a user manual. See the recommended structure
for user manual in Annex A.
5.3 Electrical hazards
5.3.1 Electrical shock
The FBS is an electrical energy storage device and contains hazardous live parts of DC and/or
AC voltage which can cause a risk of electrical shock. Electrolyte is to be considered as carrying
dangerous voltages.
Batteries are sources of dangerous voltages and energy (current flow) also when they are not
connected to an external power circuit. In flow batteries the amount of residual energy is, when
no electrolyte circulates, limited to the charge stored in the electrolyte remaining in the stack
itself. In all cases protective measures according to IEC 60364-4-41 shall be implemented.
5.3.2 Short-circuits
The electrical energy stored in an FBS can be released in an inadvertent and uncontrolled
manner due to short-circuiting the terminals. Because of its considerable level of energy and
subsequent high current, the heat generated can melt metal, produce sparks, cause explosion,
or vaporize fluid.
To avoid short-circuits, protective devices such as insulation shrouds, fuses and circuit breakers
shall be installed in a way that a short-circuit does not occur under any foreseeable conditions.
For the type of conductor arrangement of unprotected sections, IEC 60364-4-43 shall be taken
into consideration.
For protective measures, the FBS shall mitigate a short-circuit fault which occurs outside stacks
by:
– stopping the supply of energy and fluids to the flow battery cells;
– stopping PCS and opening circuit breaker(s); and,
– interrupting the short-circuit current path by using fuses between stacks.
It is suggested that each stack has a fuse to break the short-circuit path. Specific location and
quantity of fuses and/or circuit breakers shall be agreed and decided between the manufacturer
and the system user in consideration of cell protection and system safety.
The intrinsic safety of the stack under short-circuit conditions shall be verified according to
Annex B.
5.3.3 Leakage currents
In a system in which no point of the battery installation is directly connected to earth, ground
faults in the FBS are, due to the large amount of fluid in the fluid handling parts (pumps, pipes,
stacks, tanks), a particular problem, and system operators shall be well informed of this matter.
Ground faults can cause the following significant risks:
– electrocution when a person accesses the fluid leaking from piping, cells and/or other
components of the fluid system;
NOTE 1 In this case a person's body becomes a part of the circuit of the leakage current.
– arcs and fire when short-current is established by the fluid leaking from piping, cells and/or
other components of the fluid system.
NOTE 2 The criticality of arcs and fire depend on the electrical conductivity of the fluid. If the fluid has low electrical
conductivity, leakage current is small and severity of the risk is low. This also depends on the configuration of stacks.
Thus, the detection level is designed taking dangerous leakage current level into account.
The circuit of the FBS shall be properly insulated from other local conductive parts. The
minimum insulation resistance between the battery circuit and other local conductive parts shall
meet the requirements of IEC 62485-2:2010, 6.4. The minimum insulation resistance between
them shall be greater than 100 Ω per volt of the nominal voltage of the FBS.
The insulation shall resist the environmental effects of temperature, dampness, dust, gases,
steam, and mechanical stress.
Before carrying out any test, the absence of hazardous voltage between the battery and the
associated rack or enclosure shall be verified.
The battery shall be isolated from the external circuit before an insulation-to-ground resistance
determination test is carried out.
The insulation shall be verified in accordance with the test method in 11.2.
Protective devices for detecting grounding faults shall be provided in the FBS or in the external
system, such as a power conversion system, in order to account for a malfunction in the
insulation.
5.4 Hazards of gaseous emissions
5.4.1 General
Flow batteries can produce gases that can be explosive (hydrogen), toxic (bromine), or
corrosive, or that can affect the respiratory system. The quantities produced depend on the
operating conditions of the FBS and their release to the environment shall be managed with
adequate safety features (e.g. ventilation, absorption traps, scrubbers, voltage limits).
In general, gases are produced in the stacks and accumulated in the system. For example, in
the case of the FBS, gases are accumulated in the top portion of the tanks.
Since gas generation and accumulation depend on the characteristics and construction of
individual FBS, the gas hazard presents different levels of risk in individual FBS.
– 12 – IEC 62932-2-2:2020 © IEC 2020
When hydrogen is produced in an FBS, for example, the generation rate of hydrogen increases
as the FBS is charged above the rated voltage range. The correlation between the charging
voltage and the gas generation cannot be expressed by a common equation, however, because
the gas generation rate depends highly on the characteristics of cell components and fluids
which can vary between manufacturers.
The gas emission and its mitigation shall be considered in the flow battery design process. It is
suggested to install necessary gas monitoring equipment with alarms and appropriate interlocks.
5.4.2 Harmful gas
5.4.2.1 Explosive gas
The risk level of explosive gases increases if the following hazards coincide:
– generation and accumulation of combustible gases,
– their mixture with oxygen,
– presence of ignition sources.
The FBS shall have protective measures against the above hazards, including but not limited
to:
– reduction in the generation of combustible gases,
– dilution of combustible gases,
– prevention of diffusion of gases outside the volume where they are generated,
– elimination of ignition sources,
– prevention of external oxygen ingress.
5.4.2.2 Toxic gas
The risks caused by toxic gases increase if the following hazards coincide:
– generation and accumulation of toxic gases,
– human access to the vicinity of toxic gases.
The FBS shall have protective measures against the above hazards, including but not limited
to:
– elimination of toxic gases,
– dilution of toxic gases,
– collection of toxic gases by a scrubber,
– limitation of human access.
5.4.2.3 Corrosive gas
The risk level of corrosive gases increases if the following hazards coincide:
– generation and accumulation of corrosive gases,
– human access to the vicinity of corrosive gases.
The FBS shall have protective measures against the above hazards, including but not limited
to:
– construction of the system with corrosion-resistant material,
– elimination of corrosive gases,
– dilution of corrosive gases,
– collection of corrosive gases by a scrubber,
– limitation of human access.
5.4.2.4 Gases affecting the respiratory system
There are cases where gases affecting the respiratory system are generated and accumulated.
The risks caused by gases increase if the following hazards coincide:
– generation and accumulation of gases affecting the respiratory system,
– human access to the vicinity of gases affecting the respiratory system.
The flow battery system shall have protective measures against the above hazards, including
but not limited to:
– elimination of gases affecting the respiratory system,
– dilution of gases affecting the respiratory system,
– collection of gases affecting the respiratory system by a scrubber,
– limitation of human access.
5.4.3 Ventilation
5.4.3.1 General
The manufacturer shall specify the ventilation requirements for the room where the FBS is
installed. This specification shall involve warning signs, operator access limitation, mitigation
of static discharges, numbers of air exchanges in m /h, required air flow patterns and exhaust
direction. When the FBS is installed outdoors, the safety requirements and procedures for
approaching personnel shall be specified. The manufacturer shall provide data and a
measurement method used to determine the gas emission rating, and ventilation measures shall
be implemented based on IEC 60079-10-1. Reference shall be made to the theoretical minimum
ventilation flow rate to dilute the gases, which is given in IEC 60079-10-1.
Ventilation is required to ensure that no combustible or harmful gases reach a critical
concentration level. The ventilation requirement shall be met by either one or a combination of
the following methods:
– natural ventilation,
– forced ventilation through the room or enclosure.
5.4.3.2 Natural ventilation
When natural ventilation is used, battery rooms or enclosures shall be equipped with an inlet
and an outlet for the air with a minimum free opening area which meets the ventilation
requirements.
5.4.3.3 Forced ventilation
When forced ventilation is used, gases which are released from the FBS into the room or
enclosure shall be expelled to the atmosphere using a ventilation system, which may combine
an opening and fan. If forced ventilation is essential for the safe operation of the FBS, then an
appropriate interlock shall prevent its operation when the forced ventilation is not operating or
has failed.
5.4.4 Warning sign
Appropriate warning signs which prohibit sparks, smoking, open flame, and electrostatic
discharges shall be placed at the entrance of the hazardous area as determined in accordance
with IEC 60079-10-1.
– 14 – IEC 62932-2-2:2020 © IEC 2020
5.4.5 Close vicinity to emissions
The dilution of gases is not always fully achieved in the close vicinity of the exhaust of released
gases or at the outlet of direct forced ventilation, therefore a safety distance from the outlet
shall be observed. The dispersion of gases depends on the gas emission rate and the type of
ventilation close to the source of emission.
5.5 Hazard posed by liquids
5.5.1 General
The impact of the fluid involved in the FBS leakage can be categorized in terms of toxicity,
corrosiveness, environmental impacts, and flammability.
Since the fluids are flowing through the fluid system, there is a possibility that a leakage will
continue unattended or unmitigated if the detection of the leakage and/or the protection against
the leakage are inappropriate. In addition, fluids supplied to the stacks are stored in the common
tank in a large volume. The following are the basic measures against such hazards and are
further described in 5.5.2 to 5.5.5:
– ensuring the sealing performance of the fluid system,
– incorporating corrosion resistance in the design and the material of the parts that come into
contact with the electrolyte,
– detecting leakage and taking appropriate measures,
– preventing leakage to the surroundings, and,
– providing information and markings concerning the fluid.
5.5.2 Detection of electrolyte leakage
Leakage shall be detected by appropriate protection measures such as a leakage sensor. The
detection and protective functions shall be verified appropriately in accordance with 11.5.
The detection of the fluid shall initiate the necessary countermeasures such as stopping the
pumps and closing the valves.
5.5.3 Protective measures against leakage
It is required that the flow battery energy system (FBES) has a collecting tray (also known as
collecting basin) under the tanks, which is stable to liquids and has a volume at least equal to
the largest tank size of the FBS. Refer to the local safety regulations for other or additional
protective measures.
5.5.4 Specific information
The manufacturer shall provide information relevant to the fluids which details:
– the primary emergency measures that shall be taken if there is:
a) exposure and/or contamination of persons by substances emitted from the FBS,
b) contamination of the environment by substances emitted from the FBS,
– personal protective equipment:
A material safety data sheet (MSDS) shall indicate that the use of synthetic clothing which
can cause electrostatic discharge is not recommended in a hazardous area where explosive
gases are present and that personal protective equipment shall include flame retardant and
anti-static clothing.
The following four pieces of information shall be indicated on each tank:
– content and international sign (Global Harmonized System (GHS)) if necessary depending
on the chemistry,
– volume,
– polarity,
– warning label in case the tank contains hazardous liquids.
5.5.5 Flow path identification
Most flow batteries operate with two distinct fluids in which the electrochemically active species
are dissolved, suspended or present as gases.
Each of the fluids may require particular attention and methods of containment in case of
spillage or maintenance.
To reduce the risk of hazards during intervention on the fluid system, the fluid pipes shall be
clearly identified with the name of positive fluid or negative fluid written in two distinct colours
on the tanks and pipes, together with an arrow indicating the flow direction in the relevant pipes.
Symbols such as "+" as positive and "−" as negative are also available for identification marking.
5.6 Hazards of mechanical cause
The flow battery is a complex assembly of electricity and fluid-carrying components housing
large volumes of chemicals.
All these structural components shall be properly dimensioned and tested taking into
consideration temperature and pressure at specified conditions, material aging processes and
extreme conditions of temperature and pressure.
Particular attention shall also be given to the fact that the fluids are chemically aggressive and
can cause an accelerated loss of mechanical stability and cross-section loss.
5.7 Operational hazards and measures
5.7.1 General
When the flow battery is designed to work with other equipment upstream and/or downstream,
such as a control centre upstream, a signal interface or other means shall be provided to enable
a coordinated operation, including start, stop, emergency shutdown, charge and discharge.
Improper integration can cause unintentional operation which potentially leads to a hazardous
situation.
Proper coordinated operation shall be confirmed by appropriate methods. The verification
method shall be in accordanc
...
IEC 62932-2-2 ®
Edition 1.0 2020-02
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Flow battery energy systems for stationary applications –
Part 2-2: Safety requirements
Systèmes de production d’énergie à batteries d’accumulateurs à circulation
d’électrolyte pour les applications stationnaires –
Partie 2-2: Exigences de sécurité
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IEC 62932-2-2 ®
Edition 1.0 2020-02
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Flow battery energy systems for stationary applications –
Part 2-2: Safety requirements
Systèmes de production d’énergie à batteries d’accumulateurs à circulation
d’électrolyte pour les applications stationnaires –
Partie 2-2: Exigences de sécurité
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.220.99 ISBN 978-2-8322-8538-1
– 2 – IEC 62932-2-2:2020 © IEC 2020
CONTENTS
FOREWORD . 5
INTRODUCTION . 7
1 Scope . 8
2 Normative references . 8
3 Terms, definitions and abbreviated terms . 9
3.1 Terms and definitions . 9
3.2 Abbreviated terms . 9
4 Procedure of the risk analysis . 9
5 Safety requirements and protective measures . 10
5.1 General . 10
5.2 Risk information . 10
5.3 Electrical hazards . 10
5.3.1 Electrical shock . 10
5.3.2 Short-circuits . 10
5.3.3 Leakage currents . 11
5.4 Hazards of gaseous emissions . 11
5.4.1 General . 11
5.4.2 Harmful gas . 12
5.4.3 Ventilation . 13
5.4.4 Warning sign . 13
5.4.5 Close vicinity to emissions . 14
5.5 Hazard posed by liquids . 14
5.5.1 General . 14
5.5.2 Detection of electrolyte leakage . 14
5.5.3 Protective measures against leakage . 14
5.5.4 Specific information . 14
5.5.5 Flow path identification . 15
5.6 Hazards of mechanical cause . 15
5.7 Operational hazards and measures . 15
5.7.1 General . 15
5.7.2 Start . 15
5.7.3 Remote monitoring and control systems . 16
5.7.4 Protection . 16
5.7.5 Auxiliary power failure . 16
6 Instructions . 16
7 Identification labels or marking . 16
7.1 Name plate information . 16
7.2 Warning label information and location . 17
8 Transport, storage, disposal and environmental aspects . 17
8.1 Packing and transport . 17
8.2 Dismantling, disposal, and recycling . 17
9 Inspection . 17
10 Maintenance . 18
11 Verification tests for protective measures . 18
11.1 General . 18
11.1.1 Tests . 18
11.1.2 Test object . 19
11.1.3 Test category . 19
11.2 Dielectric strength of the parts in contact with the fluid . 19
11.2.1 Requirements . 19
11.2.2 Category . 19
11.2.3 Number of samples . 19
11.2.4 Test and acceptance criteria . 19
11.3 Operational sequence . 19
11.3.1 Requirements . 19
11.3.2 Category . 19
11.3.3 Number of samples . 19
11.3.4 Test . 20
11.3.5 Acceptance criteria . 20
11.4 Emergency stop . 20
11.4.1 Requirement . 20
11.4.2 Category . 20
11.4.3 Number of samples . 20
11.4.4 Test . 20
11.4.5 Acceptance criteria . 20
11.5 Protection . 20
11.5.1 Requirements . 20
11.5.2 Category . 21
11.5.3 Number of samples . 21
11.5.4 Test . 21
11.5.5 Acceptance criteria . 21
11.6 Safety requirement for stacks . 21
Annex A (informative) Recommended structure of user manual . 22
A.1 General . 22
A.2 Table of contents . 22
A.3 Safety warning . 22
A.4 Introduction . 22
A.5 Product description . 22
A.5.1 Overview . 22
A.5.2 Technical specifications . 23
A.5.3 System structure. 23
A.5.4 Applications . 23
A.5.5 Operational sequence . 23
A.6 Site requirements . 23
A.6.1 Location and load . 23
A.6.2 Access and clearance . 23
A.6.3 Precautionary measures for fluid containment. 23
A.6.4 Ventilation . 24
A.6.5 Temperature . 24
A.7 Operation . 24
A.7.1 General . 24
A.7.2 Checks before operation . 24
A.7.3 Energizing and de-energizing the system . 24
– 4 – IEC 62932-2-2:2020 © IEC 2020
A.7.4 Valve status . 24
A.7.5 Specific operations . 24
A.7.6 Notices for operation . 24
A.8 Alarms and fault finding . 25
A.9 Maintenance . 25
A.10 Contact information . 25
Annex B (normative) Safety requirements for stacks . 26
B.1 General . 26
B.2 External short-circuit of the stack . 26
B.2.1 Requirements . 26
B.2.2 Category . 26
B.2.3 Number of samples . 26
B.2.4 Test . 26
B.2.5 Acceptance criteria . 26
B.3 Heat shock strength . 27
B.3.1 Requirements . 27
B.3.2 Category . 27
B.3.3 Number of samples . 27
B.3.4 Test . 27
B.3.5 Acceptance criteria . 27
B.4 Leakage of the stack . 27
B.4.1 Requirements . 27
B.4.2 Category . 28
B.4.3 Number of samples . 28
B.4.4 Test . 28
B.4.5 Acceptance criteria . 28
Bibliography . 29
Figure 1 – Flow battery energy system . 7
Table 1 – List of verification tests for protective measurements . 18
Table B.1 – List of verification tests for stacks for protective measurements . 26
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
FLOW BATTERY ENERGY SYSTEMS FOR STATIONARY APPLICATIONS –
Part 2-2: Safety requirements
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The objective 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,
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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
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3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
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any IEC Publication and the corresponding national or regional publication shall be clearly indicated in the latter.
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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 edition.
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 62932-2-2 has been prepared by IEC technical committee 21:
Secondary cells and batteries, in collaboration with IEC technical committee 105: Fuel cell
technologies.
The text of this International Standard is based on the following documents:
FDIS Report on voting
21/1029/FDIS 21/1035/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.
A list of all parts in the IEC 62932 series, published under the general title Flow battery energy
systems for stationary applications, can be found on the IEC website.
– 6 – IEC 62932-2-2:2020 © IEC 2020
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.
INTRODUCTION
A flow battery system (FBS) can be utilized in a flow battery energy system (FBES). Such an
FBES can consist of:
– a flow battery system,
– a power conversion system,
– other equipment and surroundings.
The FBES is connected to the external power input/output via a point of connection (POC).
This document covers the domain of the FBES, as shown in Figure 1. Energy to the auxiliary
systems such as the battery management system (BMS), the battery support system (BSS),
and the power conversion system (PCS) may be supplied by one of the following:
a) direct connection to the external power source;
b) the internal power source of the FBES or FBS itself.
Figure 1 – Flow battery energy system
– 8 – IEC 62932-2-2:2020 © IEC 2020
FLOW BATTERY ENERGY SYSTEMS FOR STATIONARY APPLICATIONS –
Part 2-2: Safety requirements
1 Scope
This part of IEC 62932 applies to flow battery systems for stationary applications and their
installations with a maximum voltage not exceeding 1 500 V DC in compliance with
IEC 62932-1.
This document defines the requirements and test methods for risk reduction and protection
measures against significant hazards relevant to flow battery systems, to persons, property and
the environment, or to a combination of them.
This document is applicable to stationary flow battery systems intended for indoor and outdoor
commercial and industrial use in non-hazardous (unclassified) areas.
This document covers significant hazards, hazardous situations and events, with the exception
of those associated with natural disaster, relevant to flow battery systems, when they are used
as intended and under the conditions foreseen by the manufacturer including reasonably
foreseeable misuse thereof.
The requirements described in this document are not intended to constrain innovations. When
considering fluids, materials, designs or constructions not specifically dealt with in this
document, these alternatives are evaluated as to their ability to yield levels of safety equivalent
to those specified in this document.
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 60079-10-1, Explosive atmospheres – Part 10-1: Classification of areas – Explosive gas
atmospheres
IEC 60364-4-41, Low-voltage electrical installations – Part 4-41: Protection for safety –
Protection against electric shock
IEC 60364-4-43, Low-voltage electrical installations – Part 4-43: Protection for safety –
Protection against overcurrent
IEC 60364-6, Low voltage electrical installations – Part 6: Verification
IEC 61936-1, Power installations exceeding 1 kV a.c. – Part 1: Common rules
IEC 62485-2:2010, Safety requirements for secondary batteries and battery installations –
Part 2: Stationary batteries
IEC 62932-1, Flow battery energy systems for stationary applications – Part 1: Terminology and
general aspects
ISO 7010, Graphical symbols – Safety colours and safety signs – Registered safety signs
3 Terms, definitions and abbreviated terms
3.1 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 62932-1 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
3.2 Abbreviated terms
BMS battery management system
BSS battery support system
EES electrical energy storage
FBES flow battery energy system
FBS flow battery system
FMEA failure mode and effects analysis
FTA fault tree analysis
GHS global harmonized system
HAZOP hazard and operability study
MSDS material safety data sheet
PCS power conversion system
POC point of connection
SDS safety data sheet
UPS uninterruptible power system
4 Procedure of the risk analysis
A written risk analysis shall be performed on an FBES to ensure that:
a) all reasonably foreseeable hazards and hazardous events, including reasonably
foreseeable misuse throughout the anticipated lifetime, have been identified;
b) the risk for each of these hazards has been estimated from the combination of its probability
of occurrence and of its foreseeable severity;
c) the two factors which determine each one of the estimated risks (probability and severity)
have been eliminated or reduced to a level not exceeding the acceptable risk level as far
as reasonably possible according to the following principles in the order given:
– eliminate hazards or reduce risks by inherent design measures,
– take necessary protective measures in relation to risks that cannot be reduced by
inherent design measures,
– inform intended users and where appropriate other persons of the residual risks, indicate
whether any particular training is required and specify any need to use personal
protective equipment.
For example, failure mode and effects analysis (FMEA), fault tree analysis (FTA) methods,
hazard and operability study (HAZOP), and/or the following International Standards shall be
used as guidance:
• IEC 60812;
• IEC 61025.
– 10 – IEC 62932-2-2:2020 © IEC 2020
5 Safety requirements and protective measures
5.1 General
Each secondary battery has a different structure and therefore only the features critical or
specific to the flow battery shall be taken into consideration. The flow battery energy system as
shown in Figure 1 differs from other secondary batteries, in that a system for circulating the
electrolyte is present. The fluid circulating system consists of tanks, pumps, piping, sensors
and some safety-relevant devices.
From a chemical safety point of view, since fluid is contained in tanks, pipes and stacks, the
sealing is an important factor. There is also the possibility of hazardous gases being present,
requiring that appropriate countermeasures be implemented.
Clause 5 specifies the safety requirements and protective measures in consideration of the
above-mentioned aspects.
5.2 Risk information
The manufacturer shall provide the user with risk information based on the risk analysis to
describe hazards and the appropriate measures taken or to be taken for mitigation purposes.
The information shall include a safety data sheet (SDS).
The information can be provided in the form of a user manual. See the recommended structure
for user manual in Annex A.
5.3 Electrical hazards
5.3.1 Electrical shock
The FBS is an electrical energy storage device and contains hazardous live parts of DC and/or
AC voltage which can cause a risk of electrical shock. Electrolyte is to be considered as carrying
dangerous voltages.
Batteries are sources of dangerous voltages and energy (current flow) also when they are not
connected to an external power circuit. In flow batteries the amount of residual energy is, when
no electrolyte circulates, limited to the charge stored in the electrolyte remaining in the stack
itself. In all cases protective measures according to IEC 60364-4-41 shall be implemented.
5.3.2 Short-circuits
The electrical energy stored in an FBS can be released in an inadvertent and uncontrolled
manner due to short-circuiting the terminals. Because of its considerable level of energy and
subsequent high current, the heat generated can melt metal, produce sparks, cause explosion,
or vaporize fluid.
To avoid short-circuits, protective devices such as insulation shrouds, fuses and circuit breakers
shall be installed in a way that a short-circuit does not occur under any foreseeable conditions.
For the type of conductor arrangement of unprotected sections, IEC 60364-4-43 shall be taken
into consideration.
For protective measures, the FBS shall mitigate a short-circuit fault which occurs outside stacks
by:
– stopping the supply of energy and fluids to the flow battery cells;
– stopping PCS and opening circuit breaker(s); and,
– interrupting the short-circuit current path by using fuses between stacks.
It is suggested that each stack has a fuse to break the short-circuit path. Specific location and
quantity of fuses and/or circuit breakers shall be agreed and decided between the manufacturer
and the system user in consideration of cell protection and system safety.
The intrinsic safety of the stack under short-circuit conditions shall be verified according to
Annex B.
5.3.3 Leakage currents
In a system in which no point of the battery installation is directly connected to earth, ground
faults in the FBS are, due to the large amount of fluid in the fluid handling parts (pumps, pipes,
stacks, tanks), a particular problem, and system operators shall be well informed of this matter.
Ground faults can cause the following significant risks:
– electrocution when a person accesses the fluid leaking from piping, cells and/or other
components of the fluid system;
NOTE 1 In this case a person's body becomes a part of the circuit of the leakage current.
– arcs and fire when short-current is established by the fluid leaking from piping, cells and/or
other components of the fluid system.
NOTE 2 The criticality of arcs and fire depend on the electrical conductivity of the fluid. If the fluid has low electrical
conductivity, leakage current is small and severity of the risk is low. This also depends on the configuration of stacks.
Thus, the detection level is designed taking dangerous leakage current level into account.
The circuit of the FBS shall be properly insulated from other local conductive parts. The
minimum insulation resistance between the battery circuit and other local conductive parts shall
meet the requirements of IEC 62485-2:2010, 6.4. The minimum insulation resistance between
them shall be greater than 100 Ω per volt of the nominal voltage of the FBS.
The insulation shall resist the environmental effects of temperature, dampness, dust, gases,
steam, and mechanical stress.
Before carrying out any test, the absence of hazardous voltage between the battery and the
associated rack or enclosure shall be verified.
The battery shall be isolated from the external circuit before an insulation-to-ground resistance
determination test is carried out.
The insulation shall be verified in accordance with the test method in 11.2.
Protective devices for detecting grounding faults shall be provided in the FBS or in the external
system, such as a power conversion system, in order to account for a malfunction in the
insulation.
5.4 Hazards of gaseous emissions
5.4.1 General
Flow batteries can produce gases that can be explosive (hydrogen), toxic (bromine), or
corrosive, or that can affect the respiratory system. The quantities produced depend on the
operating conditions of the FBS and their release to the environment shall be managed with
adequate safety features (e.g. ventilation, absorption traps, scrubbers, voltage limits).
In general, gases are produced in the stacks and accumulated in the system. For example, in
the case of the FBS, gases are accumulated in the top portion of the tanks.
Since gas generation and accumulation depend on the characteristics and construction of
individual FBS, the gas hazard presents different levels of risk in individual FBS.
– 12 – IEC 62932-2-2:2020 © IEC 2020
When hydrogen is produced in an FBS, for example, the generation rate of hydrogen increases
as the FBS is charged above the rated voltage range. The correlation between the charging
voltage and the gas generation cannot be expressed by a common equation, however, because
the gas generation rate depends highly on the characteristics of cell components and fluids
which can vary between manufacturers.
The gas emission and its mitigation shall be considered in the flow battery design process. It is
suggested to install necessary gas monitoring equipment with alarms and appropriate interlocks.
5.4.2 Harmful gas
5.4.2.1 Explosive gas
The risk level of explosive gases increases if the following hazards coincide:
– generation and accumulation of combustible gases,
– their mixture with oxygen,
– presence of ignition sources.
The FBS shall have protective measures against the above hazards, including but not limited
to:
– reduction in the generation of combustible gases,
– dilution of combustible gases,
– prevention of diffusion of gases outside the volume where they are generated,
– elimination of ignition sources,
– prevention of external oxygen ingress.
5.4.2.2 Toxic gas
The risks caused by toxic gases increase if the following hazards coincide:
– generation and accumulation of toxic gases,
– human access to the vicinity of toxic gases.
The FBS shall have protective measures against the above hazards, including but not limited
to:
– elimination of toxic gases,
– dilution of toxic gases,
– collection of toxic gases by a scrubber,
– limitation of human access.
5.4.2.3 Corrosive gas
The risk level of corrosive gases increases if the following hazards coincide:
– generation and accumulation of corrosive gases,
– human access to the vicinity of corrosive gases.
The FBS shall have protective measures against the above hazards, including but not limited
to:
– construction of the system with corrosion-resistant material,
– elimination of corrosive gases,
– dilution of corrosive gases,
– collection of corrosive gases by a scrubber,
– limitation of human access.
5.4.2.4 Gases affecting the respiratory system
There are cases where gases affecting the respiratory system are generated and accumulated.
The risks caused by gases increase if the following hazards coincide:
– generation and accumulation of gases affecting the respiratory system,
– human access to the vicinity of gases affecting the respiratory system.
The flow battery system shall have protective measures against the above hazards, including
but not limited to:
– elimination of gases affecting the respiratory system,
– dilution of gases affecting the respiratory system,
– collection of gases affecting the respiratory system by a scrubber,
– limitation of human access.
5.4.3 Ventilation
5.4.3.1 General
The manufacturer shall specify the ventilation requirements for the room where the FBS is
installed. This specification shall involve warning signs, operator access limitation, mitigation
of static discharges, numbers of air exchanges in m /h, required air flow patterns and exhaust
direction. When the FBS is installed outdoors, the safety requirements and procedures for
approaching personnel shall be specified. The manufacturer shall provide data and a
measurement method used to determine the gas emission rating, and ventilation measures shall
be implemented based on IEC 60079-10-1. Reference shall be made to the theoretical minimum
ventilation flow rate to dilute the gases, which is given in IEC 60079-10-1.
Ventilation is required to ensure that no combustible or harmful gases reach a critical
concentration level. The ventilation requirement shall be met by either one or a combination of
the following methods:
– natural ventilation,
– forced ventilation through the room or enclosure.
5.4.3.2 Natural ventilation
When natural ventilation is used, battery rooms or enclosures shall be equipped with an inlet
and an outlet for the air with a minimum free opening area which meets the ventilation
requirements.
5.4.3.3 Forced ventilation
When forced ventilation is used, gases which are released from the FBS into the room or
enclosure shall be expelled to the atmosphere using a ventilation system, which may combine
an opening and fan. If forced ventilation is essential for the safe operation of the FBS, then an
appropriate interlock shall prevent its operation when the forced ventilation is not operating or
has failed.
5.4.4 Warning sign
Appropriate warning signs which prohibit sparks, smoking, open flame, and electrostatic
discharges shall be placed at the entrance of the hazardous area as determined in accordance
with IEC 60079-10-1.
– 14 – IEC 62932-2-2:2020 © IEC 2020
5.4.5 Close vicinity to emissions
The dilution of gases is not always fully achieved in the close vicinity of the exhaust of released
gases or at the outlet of direct forced ventilation, therefore a safety distance from the outlet
shall be observed. The dispersion of gases depends on the gas emission rate and the type of
ventilation close to the source of emission.
5.5 Hazard posed by liquids
5.5.1 General
The impact of the fluid involved in the FBS leakage can be categorized in terms of toxicity,
corrosiveness, environmental impacts, and flammability.
Since the fluids are flowing through the fluid system, there is a possibility that a leakage will
continue unattended or unmitigated if the detection of the leakage and/or the protection against
the leakage are inappropriate. In addition, fluids supplied to the stacks are stored in the common
tank in a large volume. The following are the basic measures against such hazards and are
further described in 5.5.2 to 5.5.5:
– ensuring the sealing performance of the fluid system,
– incorporating corrosion resistance in the design and the material of the parts that come into
contact with the electrolyte,
– detecting leakage and taking appropriate measures,
– preventing leakage to the surroundings, and,
– providing information and markings concerning the fluid.
5.5.2 Detection of electrolyte leakage
Leakage shall be detected by appropriate protection measures such as a leakage sensor. The
detection and protective functions shall be verified appropriately in accordance with 11.5.
The detection of the fluid shall initiate the necessary countermeasures such as stopping the
pumps and closing the valves.
5.5.3 Protective measures against leakage
It is required that the flow battery energy system (FBES) has a collecting tray (also known as
collecting basin) under the tanks, which is stable to liquids and has a volume at least equal to
the largest tank size of the
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