IEC 62933-4-2:2025

IEC 62933-4-2 ®
Edition 1.0 2025-02
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Electric energy storage (EES) systems –
Part 4-2: Guidance on environmental issues – Assessment of the environmental
impact of battery failure in an electrochemical based storage system

Systèmes de stockage de l’énergie électrique (EES) –
Partie 4-2: Recommandations relatives aux problèmes environnementaux –
Évaluation de l’impact environnemental d’une défaillance de batterie dans un
système de stockage d’énergie électrochimique
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IEC 62933-4-2 ®
Edition 1.0 2025-02
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Electric energy storage (EES) systems –

Part 4-2: Guidance on environmental issues – Assessment of the environmental

impact of battery failure in an electrochemical based storage system

Systèmes de stockage de l’énergie électrique (EES) –

Partie 4-2: Recommandations relatives aux problèmes environnementaux –

Évaluation de l’impact environnemental d’une défaillance de batterie dans un

système de stockage d’énergie électrochimique

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 13.020.30, 27.010 ISBN 978-2-8327-0147-8

– 2 – IEC 62933-4-2:2025 © IEC 2025
CONTENTS
FOREWORD . 4
1 Scope . 6
2 Normative references. 6
3 Terms, definitions and abbreviated terms . 6
3.1 Terms and definitions . 6
3.2 Abbreviated terms . 8
4 General . 8
5 Failure of the electrochemical accumulation system in a BESS resulting in
environmental issues . 8
5.1 General . 8
5.2 View of the subsystem structure in a BESS and the battery-related failure
site . 9
5.3 Classification of BESS types . 9
5.4 Failure of batteries in the electrochemical accumulation subsystem of a
BESS . 10
6 Guidelines for assessing the environmental impact of a failure of the battery of the
electrochemical accumulation subsystem of the BESS . 11
6.1 General . 11
6.2 Root causes of battery and flow battery failures resulting in impact on the
environment . 11
6.2.1 General . 11
6.2.2 Root causes resulting in battery and flow battery failures . 12
6.2.3 Environmental impacts upon disassembly and disposal of a failed
battery . 14
6.3 Reporting the assessment . 14
Annex A (informative) Summary of typical properties of commercially available
electrochemical energy storage systems for BESS installations . 16
Annex B (informative) Potential environmental impacts related to the type of battery
in the BESS . 22
B.1 General . 22
B.2 Cells with non-aqueous electrolyte – C-A type . 22
B.3 Cells with aqueous electrolyte – C-B type . 22
B.4 Cells with solid electrolyte and operating at temperatures above 250 °C –C-
C type . 23
B.5 Cells with aqueous but recirculating electrolyte or flow cells – C-D type . 23
B.6 Cells with any other electrochemical couple, electrolyte and energy storage
concept or combinations thereof – C-Z type . 23
B.7 Environmental impacts upon disassembly and disposal of a failed battery . 23
Annex C (informative) Selected BESS application scenarios . 24
Annex D (informative) Description of batteries used in BESS . 25
D.1 General . 25
D.2 Cells with non-aqueous electrolyte – C-A type . 25
D.3 Cells with aqueous electrolyte – C-B type . 26
D.4 Cells with solid electrolyte operating at temperatures above 250 °C –
C-C type . 26
D.5 Cells with aqueous but recirculating electrolyte or flow cells – C-D type . 27
D.6 Cells with any other electrochemical couple, electrolyte and energy storage
concept or combinations thereof – C-Z type . 27

Bibliography . 28

Figure 1 – Example of a BESS structure . 9
Figure 2 – Failure sites in the electrochemical accumulation subsystem within the
scope of this document (highlighted in grey) . 10
Figure 3 – Proximate root causes leading to a battery or flow battery failure in the
BESS with associated environmental impacts . 12
Figure C.1 – BESS application scenarios. 24

Table 1 – Classification of BESS types . 10
Table 2 – Excerpt of a possible assessment report describing failures of a specific
battery and the resulting environmental impacts . 15
Table A.1 – Summary list of typical properties of commercially available
electrochemical energy storage systems in BESS installations – Part 1 . 17

– 4 – IEC 62933-4-2:2025 © IEC 2025
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ELECTRICAL ENERGY STORAGE (EES) SYSTEMS –

Part 4-2: Guidance on environmental issues –
Assessment of the environmental impact of battery
failure in an electrochemical based storage system

FOREWORD
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...