prEN IEC 62933-5-3:2023

Electrical energy storage (EES) systems Part 5-3: Safety requirements for grid-integrated EES systems – Performing unplanned modification of electrochemical based system

Systèmes de stockage de l’énergie électrique (EES) - Partie 5-3: Exigences de sécurité lors de la modification non programmée des systèmes EES électrochimiques

Električne naprave za shranjevanje energije (EES) - 5-3. del: Varnostne zahteve pri izvajanju nenačrtovanih sprememb elektrokemičnih sistemov EES

General Information

• Status: Not Published
• Publication Date: 05-Nov-2024
• Technical Committee: CLC/SR 120 - Electrical Energy Storage (EES) Systems
• Drafting Committee: IEC/TC 120 - Electrical Energy Storage (EES) Systems
• Current Stage: 4060 - Enquiry results established and sent to TC, SR, BTTF - Enquiry
• Start Date: 07-Apr-2023
• Completion Date: 07-Apr-2023
• Ref Project: oSIST prEN IEC 62933-5-3:2023 - Electrical energy storage (EES) systems - Part 5-3: Safety requirements when performing unplanned modification of electrochemical based EES systems

Standards Content (Sample)

SLOVENSKI STANDARD
oSIST prEN IEC 62933-5-3:2023
01-marec-2023

Električne naprave za shranjevanje energije (EES) - 5-3. del: Varnostne zahteve pri

izvajanju nenačrtovanih sprememb elektrokemičnih sistemov EES
Electrical energy storage (EES) systems - Part 5-3: Safety requirements when
performing unplanned modification of electrochemical based EES systems
Ta slovenski standard je istoveten z: prEN IEC 62933-5-3:2023
ICS:
27.010 Prenos energije in toplote na Energy and heat transfer
splošno engineering in general
oSIST prEN IEC 62933-5-3:2023 en

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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oSIST prEN IEC 62933-5-3:2023
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oSIST prEN IEC 62933-5-3:2023
120/301/CDV
COMMITTEE DRAFT FOR VOTE (CDV)
PROJECT NUMBER:
IEC 62933-5-3 ED1
DATE OF CIRCULATION: CLOSING DATE FOR VOTING:
2023-01-13 2023-04-07
SUPERSEDES DOCUMENTS:
120/274/CD, 120/299/CC
IEC TC 120 : ELECTRICAL ENERGY STORAGE (EES) SYSTEMS
SECRETARIAT: SECRETARY:
Japan Mr Hideki HAYASHI
OF INTEREST TO THE FOLLOWING COMMITTEES: PROPOSED HORIZONTAL STANDARD:
TC 8,TC 21,SC 21A,TC 22,TC 57,TC 69
Other TC/SCs are requested to indicate their interest, if
any, in this CDV to the secretary.
FUNCTIONS CONCERNED:
EMC ENVIRONMENT QUALITY ASSURANCE SAFETY

SUBMITTED FOR CENELEC PARALLEL VOTING NOT SUBMITTED FOR CENELEC PARALLEL VOTING

Attention IEC-CENELEC parallel voting
The attention of IEC National Committees, members of
CENELEC, is drawn to the fact that this Committee Draft
for Vote (CDV) is submitted for parallel voting.
The CENELEC members are invited to vote through the
CENELEC online voting system.

This document is still under study and subject to change. It should not be used for reference purposes.

Recipients of this document are invited to submit, with their comments, notification of any relevant patent rights of

which they are aware and to provide supporting documentation.
TITLE:

Electrical energy storage (EES) systems Part 5-3: Safety requirements when performing

unplanned modification of electrochemical based EES systems
PROPOSED STABILITY DATE: 2028

Copyright © 2022 International Electrotechnical Commission, IEC. All rights reserved. It is permitted to

download this electronic file, to make a copy and to print out the content for the sole purpose of preparing National

Committee positions. You may not copy or "mirror" the file or printed version of the document, or any part of it,

for any other purpose without permission in writing from IEC.
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NOTE FROM TC/SC OFFICERS:
This CDV has reflected the observations of 120/299/CC.

And the standard title has been reviewed by WG5 experts below. In addition, there is a

comment to review this title in CH01 (serial number 02) of 120/299/CC.
The reviewed title:

“Electrical energy storage (EES) systems Part 5-3: Safety requirements when performing

unplanned modification of electrochemical based EES systems”
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1 CONTENTS

3 FOREWORD ........................................................................................................................................... 5

4 INTRODUCTION ..................................................................................................................................... 7

5 1 Scope .............................................................................................................................................. 8

6 2 Normative references ...................................................................................................................... 8

7 3 Terms and definitions ...................................................................................................................... 8

8 4 Guidelines for safety when performing unplanned modifications ................................................. 10

9 4.1 General ................................................................................................................................ 10

10 5 Changes to an accumulation subsystem ...................................................................................... 11

11 5.1 General ................................................................................................................................ 11

12 5.2 Changes in energy storage capacity ................................................................................... 12

13 5.2.1 General ........................................................................................................................ 12

14 5.2.2 Safety requirements in the re-design phase ............................................................... 13

15 5.2.3 Safety requirements in the installation and commissioning phase ............................. 13

16 5.2.4 Safety requirements for the operation and maintenance ............................................ 14

17 5.3 Changes of chemistries, design and manufacturer of an accumulation subsystem ........... 14

18 5.3.1 General ........................................................................................................................ 14

19 5.3.2 Safety requirements in the re-design phase ............................................................... 15

20 5.3.3 Safety requirements in the installation and commissioning phase ............................. 16

21 5.3.4 Safety requirements for the operation and maintenance ............................................ 17

22 6 Changes of a system component using non-OEM parts .............................................................. 17

23 6.1 General ................................................................................................................................ 17

24 6.2 Safety requirements in the re-design phase ........................................................................ 18

25 6.3 Safety requirements in the installation and commissioning phase...................................... 18

26 6.4 Safety requirements for the operation and maintenance .................................................... 19

27 7 Changes to mode of operation ...................................................................................................... 20

28 7.1 General ................................................................................................................................ 20

29 7.2 Safety requirements in the re-design phase ........................................................................ 20

30 7.3 Safety requirements in the installation and commissioning phase...................................... 21

31 7.4 Safety requirements for the operation and maintenance .................................................... 21

32 8 Changes of installation site ........................................................................................................... 22

33 8.1 General ................................................................................................................................ 22

34 8.2 Safety requirements in the re-design phase ........................................................................ 22

35 8.3 Safety requirements in the installation and commissioning phase...................................... 23

36 8.4 Safety requirements for the operation and maintenance .................................................... 24

37 9 Changes in an accumulation subsystem due to an installation of reused or repurposed

38 batteries ......................................................................................................................................... 24

39 9.1 General ................................................................................................................................ 24

40 9.2 Safety requirements in the design phase ............................................................................ 25

41 9.2.1 General ........................................................................................................................ 25

42 9.2.2 Validation of history data ............................................................................................. 25

43 9.2.3 Estimation of residual usable period and performance ............................................... 26

44 9.2.4 Safety requirements in the design of safety ................................................................ 26

45 9.3 Safety requirements in the installation and commissioning phase...................................... 29

46 9.3.1 General ........................................................................................................................ 29

47 9.3.2 Safety requirements for installation and commissioning process ............................... 29

48 9.4 Safety requirements for the operation and maintenance .................................................... 30

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49 9.4.1 General ........................................................................................................................ 30

50 9.4.2 Safety requirements for monitoring data ..................................................................... 30

51 9.4.3 Safety requirements for operation and maintenance .................................................. 31

52 Annex A (informative) An example of a safety validation method when performing unplanned

53 modifications of a BESS using Lithium ion batteries ..................................................................... 33

54 A.1 General ................................................................................................................................ 33

55 A.2 Estimation methods for deterioration of lithium-ion battery ................................................. 33

56 A.3 Safety estimation of BESS by deterioration estimation method .......................................... 33

57 Bibliography ........................................................................................................................................... 35

59 Figure 1 – Major modifications and their classification .......................................................................... 10

60 Figure 2 – An example of BESS architecture ........................................................................................ 12

61 Figure 3 – Life cycle of reused/repurposed battery ............................................................................... 25

62 Figure A.1– An example of BESS mounted a safety estimation function ............................................. 34

63 Figure A.2 – An example of a safety assessment network using an estimation function ..................... 34

65 Table 1 – Examples of relevant stakeholders ....................................................................................... 11

66 Table 2 – Examples of different batteries chemistry modifications and their categorization ................ 15

67 Table 3 – Examples of subsystems or components related safety ....................................................... 18

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71 INTERNATIONAL ELECTROTECHNICAL COMMISSION
72 ____________
74 ELECTRICAL ENERGY STORAGE (EES) SYSTEMS
76 Part 5-3: Safety requirements when performing unplanned modification of
77 electrochemical based EES systems
79 FOREWORD

80 1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising all national

81 electrotechnical committees (IEC National Committees). The object of IEC is to promote international co-operation on all

82 questions concerning standardization in the electrical and electronic fields. To this end and in addition to other activities, IEC

83 publishes International Standards, Technical Specifications, Technical Reports, Publicly Available Specifications (PAS) and

84 Guides (hereafter referred to as “IEC Publication(s)”). Their preparation is entrusted to technical committees; any IEC

85 National Committee interested in the subject dealt with may participate in this preparatory work. International, governmental

86 and non-governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely with

87 the International Organization for Standardization (ISO) in accordance with conditions determined by agreement between

88 the two organizations.

89 2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international consensus

90 of opinion on the relevant subjects since each technical committee has representation from all interested IEC National

91 Committees.

92 3) IEC Publications have the form of recommendations for international use and are Accepted by IEC National Committees in

93 that sense. While all reasonable efforts are made to ensure that the technical content of IEC Publications is accurate, IEC

94 cannot be held responsible for the way in which they are used or for any misinterpretation by any end user.

95 4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications transparently to

96 the maximum extent possible in their national and regional publications. Any divergence between any IEC Publication and

97 the corresponding national or regional publication shall be clearly indicated in the latter.

98 5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity assessment

99 services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any services carried out by

100 independent certification bodies.

101 6) All users should ensure that they have the latest edition of this publication.

102 7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and members of its

103 technical committees and IEC National Committees for any personal injury, property damage or other damage of any nature

104 whatsoever, whether direct or indirect, or for costs (including legal fees) and expenses arising out of the publication, use of,

105 or reliance upon, this IEC Publication or any other IEC Publications.

106 8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is indispensable

107 for the correct application of this publication.

108 9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of patent rights.

109 IEC shall not be held responsible for identifying any or all such patent rights.

110 International Standard IEC 62933-5-3 has been prepared by IEC technical committee 120:

111 Electrical Energy Storage (EES) Systems.
112 The text of this International Standard is based on the following documents:
FDIS Report on voting
120/XX/FDIS 120/XX/RVD
113

114 Full information on the voting for the approval of this International Standard can be found in the

115 report on voting indicated in the above table.

116 This document has been drafted in accordance with the ISO/IEC Directives, Part 2.

117 The committee has decided that the contents of this document will remain unchanged until the

118 stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to

119 the specific document. At this date, the document will be
120 • reconfirmed,
121 • withdrawn,
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122 • replaced by a revised edition, or
123 • amended.
124

125 The National Committees are requested to note that for this document the stability date

126 is 202X..

127 THIS TEXT IS INCLUDED FOR THE INFORMATION OF THE NATIONAL COMMITTEES AND WILL BE DELETED

128 AT THE PUBLICATION STAGE.
129
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130 INTRODUCTION

131 The initial design or planning cannot cover all modifications that are made to a BESS over its lifetime.

132 Unplanned modifications require a careful evaluation of their potential impact on the safety of the

133 BESS.
134

135 This document provides safety requirements, considerations and process steps when unplanned

136 modifications of the BESS are to be carried out.
137

138 Such modification activities of the BESS require appropriate attention to safety issues in the relative

139 redesign, installation, commissioning, operation and maintenance phases.
140 Unplanned modifications which are dealt with in this standard are:
141 – changes in energy storage capacity;

142 – changes of chemistries, design and manufacturer of the accumulation subsystem;

143 – changes of a subsystem component using non-OEM parts;
144 – changes to mode of operation;
145 – changes of installation site;

146 – changes in an accumulation subsystem due to an installation of reused or repurposed

147 batteries.
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148 ELECTRICAL ENERGY STORAGE (EES) SYSTEMS
149
150 Part 5-3: Safety requirements when performing unplanned modification of
151 electrochemical based EES systems
152
153 1 Scope

154 This part of IEC 62933 applies to those instances when a BESS undergoes unplanned

155 modifications. Such modifications can involve one or more of the following:
156 – changes of a subsystem component using non-OEM parts,
157 – changes to mode of operation,
158 – changes of installation site, or

159 – changes in an accumulation subsystem due to an installation of reused or repurposed

160 batteries.

161 Any such modification shall not impair the original state of safety of the BESS.

162 This document complements IEC 62933-5-2, which relates to the overall safety aspects of a

163 BESS. The requirements covered by this document are applied in addition to the requirements

164 in IEC 62933-5-2 in accordance with each situation.
165
166 2 Normative references

167 The following documents are referred to in the text in such a way that some or all of their content

168 constitutes requirements of this document. For dated references, only the edition cited applies.

169 For undated references, the latest edition of the referenced document (including any

170 amendments) applies.
171 IEC 62933-1, Electrical Energy Storage (EES) systems - Part 1: Vocabulary

172 IEC TS 62933-5-1, Electrical Energy Storage (EES) systems – Part 5-1: Safety considerations

173 for grid integrated EES systems – General specifications

174 IEC 62933-5-2, Electrical Energy Storage (EES) systems – Part 5-2: Safety requirements for

175 grid integrated EES systems – Electrochemical based system
176 IEC 63330(future IEC), Requirements for reuse of secondary batteries

177 IEC 63338(future IEC), General guidance for reuse of secondary cells and batteries

178
179 3 Terms and definitions
180 3.1
181 accumulation subsystem
182 storage subsystem

183 EESS subsystem, comprising at least one electrical energy storage, where the energy is

184 stored in some form
185

186 Note 1 to entry: Mechanical energy, electrochemical energy, electromagnetic energy are frequent forms of stored

187 energy.
188

189 Note 2 to entry: Generally, the accumulation subsystem is connected to the power conversion

190 subsystem that performs the necessary power conversion to electrical energy; however, in some cases, a power

191 conversion is embedded in the accumulation subsystem (e.g. in electrochemical secondary cells the energy is

192 directly available in the electrical form).
193 [SOURCE: IEC 62933-1: 2018, 2.27]
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194 3.2
195 battery energy storage system
196 BESS

197 electrical energy storage system with accumulation subsystem based on batteries with

198 secondary cells

199 Note 1 to entry: Battery energy storage systems can include a flow battery energy system (IEC 62932-1:2020, 3.1.15).

200 3.3
201 battery operating range

202 range of voltage, current and temperature to ensure the safe use of the accumulation subsystem

203 3.4
204 critical stakeholder

205 party concerned with the critical part of BESS safety affected by the modification

206 3.5
207 unplanned modification

208 modification that has not been intended to be carried out or planned prior to the start of

209 operation of the BESS

210 Note 1 to entry: IEC 62933-5-2 7.13.1 “Operation and maintenance plan” deals with planned modification.

211 3.6
212 OEM part
213 part supplied to or by an original equipment manufacturer (OEM)

214 Note 1 to entry: OEM parts are generally used to manufacture new equipment and can also be purchased for

215 maintenance and repair.
216 Note 2 to entry: A part that is not an OEM part is called “non-OEM part”.
217 3.7
218 relocation
219 moving an installation physically from its current location
220 3.8
221 reused battery

222 battery that is used again in the same application as it was used for when commissioned the

223 first time
224 3.9
225 repurposed battery

226 battery that is used again in a different application as it used for when commissioned the first

227 time
228 3.10
229 residual usable period
230 actual or estimated remaining length of service life
231 3.11
232 safety margin,

233 margin defined within battery operating range considering system application, environmental

234 conditions and so on for safe operation of BESS
235 3.12
236 safe-operating range,
237 range excluding safety margin from battery operating range
238 3.13
239 state of energy,
240 state of charge,
241 EESS SOE
242 EESS SOC

243 ratio between the available energy from an EES system and the actual energy storage capacity

244 [SOURCE: IEC 62933-1:(future revision), 6.2.7]
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245 3.14
246 state of health,
247 EESS SOH

248 general condition of the EES system based on measurements that indicate its actual performance

249 compared with its either nominal or rated performances

250 Note 1 to entry: The state of health includes also the temporary degradation due to faults inside the EESS subsystems.

251 [SOURCE: IEC 62933-1:(future revision), 6.2.8]
252
253 4 Guidelines for safety when performing unplanned modifications
254 4.1 General

255 The BESS, including the batteries, can be exposed to the following changes in safety conditions

256 during its operation:

257 1) Changes in safety conditions due to changes in the surrounding environment,

258 2) Changes in safety conditions due to unplanned modifications of the BESS,
259 3) Changes in safety conditions due to aging, and

260 4) Changes in safety conditions due to modifications planned at the time of the initial design.

261 This standard describes the safety measures that shall be taken for BESS in the event of items

262 1) and 2) above. The events of items 3) and 4) should be considered and addressed at the time

263 of initial design of the BESS, which is under the scope of IEC 62933-5-2.

264 NOTE: The modifications that occur in the BESS can be at the component, subsystem or system level. While the

265 primary focus of this document is on changes in safety and their evaluation at the system level, the process can also

266 require evaluation at the component or subsystem level (e.g., interactions between subsystems).

267 Figure 1 shows the modifications that affect safety, which are made by subdivision of changes

268 in items 1) and 2). This standard deals with the modifications shown in the yellow boxes in

269 Figure 1.
Unplanned modification
Changes in surrounding
Changes to BESS
environment
Changes to
Accumulation Subsystem
Changes of
mode of operation
Surrounding
subsystem components
installation site Law or regulation
condition clause 7
clause 8
Changes of chemistry, Changes in an accumulation Changes of
Changes in

design and manufacturer of subsystem due to an installation of a system components

energy storage capacity
an accumulation subsystem reused or repurposed batteries
using non-OEM parts
sub-clause 5.2
sub-clause 5.3 clause 9 clause 6
270
271 Figure 1 – Major modifications and their classification
272

273 An unplanned modification of a BESS can result in conditions where multiple safety related

274 conditions are potentially affected at the same instance.

275 In such an event, the impact on safety of the individual modifications is to be assessed and all

276 the resulting risk mitigation actions are to be implemented. The detailed requirements of

277 assessment or measures etc., are described in each clause of this standard.

278 A wide range of stakeholders are involved in the modification process. Examples of

279 stakeholders are shown in Table 1. The requirements described in this standard shall be met

280 as appropriate in cooperation with the stakeholders.
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281 NOTE: Responsibility for ensuring the BESS safety depends on each case and local regulations.

282 Table 1 – Examples of relevant stakeholders
Type of stakeholders Specific examples of stakeholders
Owner
Ownership
User
Operator
Operation
Service provider
Project manager and administrator
Overall system integrator
Engineering, Procurement and
Construction (EPC)
Subsystem integrator
Integrator performing modification *
Component manufacturer
Component vendor
Component
Additional component manufacturer *
Additional component vendor *
Certification authority of original parts
Certification body
Certification authority of additional parts *
Local government
Local
Fire-fighting agency

283 Note: The stakeholders with “*” marking can be involved in cases where there are modifications with additional parts

284 (e.g. clause 5,6 and 9).
285
286 5 Changes to an accumulation subsystem
287 5.1 General

288 The intention of this clause is to describe safety requirements, considerations and processes

289 to follow for situations where changes are made to an accumulation subsystem in a BESS.

290 This section describes the requirements when an accumulation subsystem (See Figure 2)

291 undergoes unplanned modifications.
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Control subsystem
Communication subsystem
Management subsystem Communication
interface
Protection subsystem
Auxiliary
connection
Auxiliary subsystem Auxiliary POC
terminal
Primary subsystem
Power Primary
Accumulation
Primary POC
conversion connection
subsystem
subsystem terminal
292
293 Note: ”POC” is short for “point of connection”.
294 Figure 2 – An example of BESS architecture
295

296 The unplanned modifications of the accumulation subsystem described in this section are:

297 – changes in energy storage capacity;
298 – changes of chemistry and design of an accumulation subsystem.
299
300 5.2 Changes in energy storage capacity
301 5.2.1 General

302 This clause specifies the safety requirements, considerations and processes for situations

303 where the energy storage capacity of the electrochemical accumulation subsystem is changed.

304 The energy storage capacity of the BESS can be modified when batteries are removed due to

305 their failure or added to meet a higher energy demand or a modified operating mode.

306 Note: “Energy storage capacity of the BESS” means the total energy capacity of electrochemical

307 accumulation subsystems.

308 Such changes modify the voltage vs. time profile during discharge and charge and possibly

309 bring the batteries to voltage, temperature and SOC values that were not originally planned.

310 This can mean that the existing safety measures are not adequate and the safety of the BESS

311 can be impaired.
312 The possible negative consequences of capacity changes are:

313 a) Dielectric breakdown and loss of the electrical insulation levels resulting in dangerous

314 voltages on operator-accessible surfaces,

315 b) Electric shock risks arising from changes causing malfunction of protective measures

316 and devices,

317 c) An increase of the fire load level necessitating adjustment of firefighting measures and

318 their capabilities,

319 d) An increase in the amount of thermal energy released by the accumulation subsystem

320 to be handled by the heat, ventilation and air conditioning (HVAC),
321 e) An increase of the quantity of chemicals to be handled in an emergency,
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322 f) Voltage and capacity imbalances between aged and new batteries causing accelerated

323 aging,
324 g) Management
...