INSTITUTION PROFILE / NEXT-GEN ENERGY STORAGE
International Electrotechnical Commission (IEC)
The Geneva-based nonprofit that writes international standards for batteries and storage systems
The IEC is a nonprofit membership organization that prepares international standards for electrical and electronic technologies. It does not make batteries. For energy storage, its technical committee on secondary cells and batteries (TC 21) is responsible for safety standards for the batteries themselves (IEC 62619, IEC 63056 and others), and its technical committee on electrical energy storage systems (TC 120) for standards for storage systems (the IEC 62933 series). IEC standards have no legal force of their own, however. They become de facto benchmarks when countries write them into national standards, regulations, subsidy requirements or certification schemes. This profile looks at one question: how far the IEC's influence over next-generation energy storage actually reaches.
What this article covers
- The IEC in 30 seconds
- What kind of body it is: the four types of influence
- What it does for energy storage
- How far its influence reaches (powers and geography)
- How standards get used, and who is involved
- Outlook
- Glossary, references and claim-to-source audit
1. The IEC in 30 seconds
LEGAL NAMEInternational Electrotechnical CommissionKnown as the IEC. Founded in 1906
COUNTRY / REGIONInternational (Switzerland)Headquartered in Geneva, with five regional offices
TYPE OF BODYNonprofit membership organizationIts members are national committees, one per country. Individuals and companies cannot join
MEMBERSHIP92 National Committees64 full and 28 associate members (IEC website). The 2025 Performance Report counts 167 countries (89 members and 78 affiliates)
SCALE (PEOPLE)157 Secretariat staffAs of 31 December 2025 (147.2 full-time equivalents). About 30,000 experts write the standards (all fields combined)
SCALE (INCOME)CHF 36.11 millionOperational income in 2025, including CHF 13.24 million of membership dues. Funded by dues, sales of standards and conformity assessment services
ROLE IN ENERGY STORAGEStandards for batteries and storage systemsTC 21 (secondary cells and batteries), SC 21A and TC 120 (electrical energy storage systems)
REACHCountries and schemes that adopt its standardsThe standards themselves carry no force. The IEC also runs conformity assessment systems such as IECEE
The one point to grasp first
The IEC writes standards; it does not make anyone use them. The IEC itself describes its standards as voluntary, consensus-based international standards Sourced. Even so, its influence is large, because under the World Trade Organization's Technical Barriers to Trade (TBT) Agreement, WTO members commit to using international standards as the basis for their national standards, mandatory technical regulations, and testing and certification practices Sourced. In energy storage, a study document of Japan's Fire and Disaster Management Agency names conformity to IEC 62933-5-2, among others, as a condition for relaxing rules on outdoor lithium-ion battery facilities (a proposal dated July 2022) Sourced. The standards themselves are sold (IEC 62619:2022 costs CHF 260), so this profile uses only titles, scope statements, editions and dates.
2. What kind of body it is: the four types of influence
The institutions that appear in energy storage coverage do not make batteries themselves, unlike companies. They can be grouped into four types by the route through which they influence the industry.
3. What it does for energy storage
The IEC's storage standards are written by three technical committees Sourced.
| Committee | Scope (as the IEC states it) | Publications and secretariat |
|---|---|---|
| TC 21 Secondary cells and batteries | The chemistry, dimensions, marking and performance of all rechargeable cells and batteries, the intrinsic safety of their design, and safety rules for installation, operation, maintenance and disposal. The list of covered chemistries includes lead-acid, nickel-cadmium, nickel-metal hydride, lithium-ion, high-temperature couples such as sodium-sulphur, and flow batteries. Applications include storage of energy from renewable sources in islanded and grid-connected installations (BESS). For large grid-integrated storage systems covered by TC 120, TC 21's scope ends at the interface between the storage device (the battery) and the rest of the system | 47 publications (including amendments and corrigenda). Secretariat: France |
| SC 21A Secondary cells and batteries containing alkaline or other non-acid electrolytes | Product and test specifications for sealed and vented secondary cells and batteries with alkaline or other non-acid electrolytes, which include lithium and nickel systems. It supports the application-oriented system standards written by other technical committees | 34 publications. Secretariat: France |
| TC 120 Electrical energy storage (EES) systems | Standardization of grid-integrated storage systems. It focuses on system aspects rather than the storage devices (unit parameters, test methods, planning and installation, environmental guidance, system safety) and on the interaction between storage systems and electric power systems. It considers all storage technologies; UPS-only systems are excluded | 20 publications. Secretariat: Japan |
The next table lists the main storage-related standards. Titles are the originals, and editions and dates follow the IEC website and webstore Sourced.
| Standard | Title and edition | Role |
|---|---|---|
| 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. Edition 2.0, 24 May 2022. SC 21A | Safety requirements for industrial lithium secondary cells and batteries. Applications include telecom, UPS, electrical energy storage systems and forklift trucks. Where a dedicated IEC standard exists for a special application such as road vehicles (the IEC 62660 series), that standard takes precedence. Its stability date (a guide for review) is 2026 |
| IEC 63056 | Same series - Safety requirements for secondary lithium cells and batteries for use in electrical energy storage systems. Edition 1.0, 27 March 2020. SC 21A | Safety of lithium cells and batteries in storage systems, with a maximum DC voltage of 1,500 V (nominal). The basic requirements for industrial use are in IEC 62619; this standard adds requirements specific to storage systems, from home systems to large on-grid and off-grid storage |
| IEC 61427-1 / -2 | Secondary cells and batteries for renewable energy storage - General requirements and methods of test. Part 1 (photovoltaic off-grid) is from 2013; Part 2 (on-grid) is from 2015, with Amendment 1 in 2024. TC 21 | General requirements and test methods for batteries for renewable energy storage |
| IEC 62485-5 | Safety requirements for secondary batteries and battery installations - Part 5: Safe operation of stationary lithium ion batteries. Edition 1.0, 25 November 2020. TC 21 | Safe operation of stationary lithium-ion batteries (installation safety) |
| IEC 62933 series | Electrical energy storage (EES) systems. Vocabulary (Part 1, Edition 2.0, 2024), unit parameters and testing methods (Part 2-1, 2017, and others), planning and performance assessment (Part 3-1, 20 November 2025, and others), environment (Parts 4-2 and 4-3, 2025, and others), safety (Part 5-1, 2024). TC 120 | The family of storage-system standards. Nearly all of TC 120's 20 publications belong to this series (corrigenda included) |
| IEC 62933-5-2 | Safety requirements for grid-integrated EES systems - Electrochemical-based systems. Edition 2.0, 9 December 2025, 236 pages, stability date 2029. TC 120 | Safety requirements for grid-connected electrochemical storage systems, covering the whole life cycle of a BESS from design to end of service life. It adds provisions arising from the use of an electrochemical storage subsystem on top of the general safety considerations in IEC 62933-5-1 |
| IEC 62933-5-4 | Safety test methods and procedures for grid integrated EES systems - Lithium ion battery-based systems. Edition 1.0, 11 May 2026. TC 120 | Safety test methods for storage systems that use lithium-ion batteries |
A materials engineer's view: the battery standards test the finished battery
IEC 62619 and IEC 63056 test the cell or battery itself. They are not standards for materials such as electrolytes, separators or encapsulants. Materials suppliers are affected only indirectly, because the cells that pass these tests must be built with materials of adequate heat resistance and safety. IEC 62619 also says that where a separate IEC standard exists for a special application (for example, EVs), that one takes precedence Sourced. Because the same lithium-ion cell may fall under different standards for EVs (IEC 62660), for industrial and storage use (IEC 62619) and for storage systems (IEC 63056), different test conditions can be required by application, so a supplier needs to check which standard its customer works to Our calculation.
4. How far its influence reaches (powers and geography)
| Dimension | What the IEC has | What the IEC does not have |
|---|---|---|
| Powers | The power to write and publish international standards. Approval of each technical committee's scope (by its Standardization Management Board), and operation of four conformity assessment systems, including IECEE. IECEE operates battery standards (IEC 62619:2022 is in category BATT) with a test report form | Any power to compel adoption of a standard, to stop a product being sold, to permit or inspect installations, or to pay subsidies |
| Geography | International. 167 countries took part in 2025 (89 members and 78 affiliates). Under the WTO TBT Agreement, members commit to using international standards as the basis for national standards, technical regulations and testing and certification. Affiliate countries can adopt many IEC standards free of charge | The decision by each country to write a standard into its own law. Where it is not adopted, an IEC standard is no more than non-binding reference material |
| Basis of force | The IEC calls its standards voluntary. Force arises when a country's laws, codes or subsidy requirements cite them. In Japan, JIS C 4441 was established so that IEC 62933-5-2 could be used as a basis for certification domestically (Fire and Disaster Management Agency document) | A requirement in a jurisdiction that does not cite the standard. Whether US codes designate IEC standards, as they do NFPA 855 or UL 9540, was not checked for this profile |
| Duration | Standards take 2.5 to 3 years to be published on average (IEC Performance Report). Each has a stability date at which it is reviewed. Forecast publication dates in the storage work programmes run from 2027 to 2029 | A firm commitment to standards for solid-state batteries or other new chemistries. For anything not in a work programme there is no timetable |
| Scale | 157 Secretariat staff and CHF 36.11 million of operational income (2025). 118 technical committees, 105 subcommittees and 881 working groups. Experts take part in a personal capacity and do not represent their company or National Committee | How many people sit on the storage committees, and which companies are involved (the IEC's documents do not say) |
How to read the numbers
The IEC's membership figures depend on how they are counted. The 92 National Committees on the IEC website (64 full and 28 associate members) and the 167 countries in the Performance Report to the General Assembly (89 members and 78 affiliates) are different numbers. The latter includes affiliate countries, which use IEC work without paying dues. The number of standards also differs: "around 10 000" on the website and "12 450" in the Performance Report Sourced. All of these are totals across every IEC field, not figures for energy storage. The 47 publications of TC 21, 34 of SC 21A and 20 of TC 120 include amendments and corrigenda.
5. How standards get used, and who is involved
| Organisation | Relationship to the IEC (as stated in primary sources) |
|---|---|
| ISO | TC 21 and SC 21A cooperate with ISO committees (such as ISO/TC 22/SC 37 on electrically propelled road vehicles and ISO/TC 333) on standards. On 16 June 2025 the IEC and ISO signed an agreement for a joint Single Delivery Unit for digital standards content (the SMART programme). As a rule of thumb, the IEC covers electrical and electronic fields and ISO the rest (see our ISO profiles) |
| National committee (Japan: JISC) | Japan joined in 1910 as a full member. Japan holds the secretariat of TC 120. JISC (the Japanese Industrial Standards Committee) is the national contact point |
| UL Standards & Engagement, UL Solutions and NFPA | UL 9540, UL 9540A and NFPA 855 are separate documents from other bodies, not IEC standards. UL Solutions' service page says it also offers performance and safety testing to standards such as IEC 62933-5-2. See our UL Solutions and NFPA profiles |
| Fire and Disaster Management Agency and METI | The FDMA study document refers to IEC 62933-5-2, and records a case where a JIS standard (JIS C 4412) was used as a safety requirement for a subsidy. See our METI profile |
6. Outlook
| What can be read | Primary source behind it | Type |
|---|---|---|
| IEC 62933-5-2, the safety standard for grid storage systems, has a second edition from December 2025, and IEC 62933-5-4, safety test methods for systems using lithium-ion batteries, was published in May 2026 | TC 120's publications list and the IEC webstore | Sourced |
| The stability date of IEC 62619:2022 is 2026, and the SC 21A work programme (October 2026) lists no revision project for IEC 62619. For storage-system batteries, IEC 63056 has a new Part 1 project (forecast publication August 2027) | The IEC webstore and the SC 21A work programme | Sourced Not yet confirmed |
| Work on newer batteries is under way: guidelines on test items for solid-state batteries (IEC TR 62660-5, forecast December 2028), sodium-ion batteries (IEC 63635 and 63636 for industrial use, forecast December 2028; IEC 63591 for EVs, forecast February 2028) and flow battery safety (IEC 62932-3, forecast April 2028). The forecast dates are the work programmes' own and are not commitments | The TC 21 and SC 21A work programmes | Not yet confirmed |
| New chemistries will probably enter first as guides and organized test items (technical reports), with standardization in 2028 or later. New work in TC 120 is mainly guidance for systems that combine several storage subsystems (IEC TS 62933-2-4, forecast June 2028) | The TC 21 and TC 120 work programmes (forecast publication dates) | Inference |
| With IEC 62933-5-2 now in its second edition, the national standard based on it (Japan's JIS C 4441) may come up for review | The FDMA document says JIS C 4441 was established so that IEC 62933-5-2 could be used for certification in Japan; the second edition came out in December 2025 | Inference |
7. Glossary
- National Committee (NC)
- The body through which a country joins the IEC, one per country (Japan: JISC). It sends experts to technical committees and votes.
- TC / SC
- Technical committee and subcommittee. The units that write standards by field.
- TS / TR
- Technical specification and technical report. Documents with a looser status than an international standard.
- IECEE / CB Scheme
- One of the IEC's conformity assessment systems. Participating countries' labs mutually accept each other's test reports. Batteries fall under category BATT.
- Stability date
- The year by which it is decided whether a standard is maintained or revised.
- Affiliate country
- A status that lets developing countries take part in IEC work without paying dues and adopt many standards free of charge.
8. References
- IEC Who we are (founded 1906) and What IEC does (nonprofit membership organization, about 170 countries, 30,000 experts, around 10,000 standards, four conformity assessment systems). https://www.iec.ch/what-we-do
- IEC IEC and global trade (under the WTO TBT Agreement, members commit to using international standards as the basis for national standards, mandatory technical regulations and testing and certification). https://www.iec.ch/what-we-do/iec-and-global-trade
- IEC National Committees (64 full and 28 associate members, 92 in total; individuals and companies cannot join; experts take part in a personal capacity; admission of Japan and France). https://www.iec.ch/national-committees
- IEC Technical committees and subcommittees (standards are published as voluntary, consensus-based international standards; 118 technical committees, 105 subcommittees, 881 working groups). https://www.iec.ch/technical-committees-and-subcommittees
- IEC Contact IEC Secretariat (headquarters in Geneva). https://www.iec.ch/contact
- IEC IEC Performance Report 2025 (General Assembly document GA/359/INF, 27 March 2026: 157 staff, 167 countries, operational income, 12,450 standards, the agreement with ISO). https://www.iecex.com/dmsdocument/4942/
- IEC TC 21 Dashboard - Scope (scope for secondary cells and batteries, BESS, boundary with TC 120, cooperating committees, secretariat France). https://www.iec.ch/dyn/www/f?p=103:7:::::FSP_ORG_ID:1290
- IEC TC 21 Dashboard - Publications (titles, editions and dates of IEC 61427, 62485-5 and 62660; 47 publications). https://www.iec.ch/dyn/www/f?p=103:22:0::::FSP_ORG_ID:1290
- IEC TC 21 Dashboard - Work programme (IEC TR 62660-5, IEC 62660 third editions, IEC 62932, sodium-ion batteries and other projects, with forecast publication dates). https://www.iec.ch/dyn/www/f?p=103:23:::::FSP_ORG_ID:1290
- IEC SC 21A Dashboard - Scope, Publications and Work programme (titles, editions and dates of IEC 62619 and IEC 63056; 34 publications; projects; secretariat France). https://www.iec.ch/dyn/www/f?p=103:22:0::::FSP_ORG_ID:1410
- IEC TC 120 Dashboard - Scope (scope for EES systems; secretariat Japan). https://www.iec.ch/dyn/www/f?p=103:7:::::FSP_ORG_ID:9463
- IEC TC 120 Dashboard - Publications (titles, editions and dates of the IEC 62933 series; 20 publications). https://www.iec.ch/dyn/www/f?p=103:22:0::::FSP_ORG_ID:9463
- IEC TC 120 Dashboard - Work programme (projects and forecast publication dates). https://www.iec.ch/dyn/www/f?p=103:23:::::FSP_ORG_ID:9463
- IEC Webstore IEC 62619:2022 (scope, price of CHF 260, stability date 2026). https://webstore.iec.ch/en/publication/64073
- IEC Webstore IEC 63056:2020 (scope, maximum DC voltage of 1,500 V, stability date 2026). https://webstore.iec.ch/en/publication/29224
- IEC Webstore IEC 62933-5-2:2025 (scope, Edition 2.0, 9 December 2025, 236 pages, price of CHF 405, stability date 2029). https://webstore.iec.ch/en/publication/68297
- IECEE IEC 62619:2022 (category BATT, included in the IECEE system on 15 June 2022, test report form). https://www.iecee.org/certification/iec-standards/iec-626192022
- Fire and Disaster Management Agency (Japan) Working group on risk-based fire safety measures for storage battery facilities, Document 3-1, "Review of the regulation of storage battery facilities" (July 2022; in Japanese). Purpose of JIS C 4441, the proposed relaxation for outdoor installation that names IEC 62933-5-2, and JIS C 4412. https://www.fdma.go.jp/singi_kento/kento/items/post-116/01/shiryou3-1.pdf
- UL Solutions Energy Storage System Testing and Certification (testing to standards such as IEC 62933-5-2). https://www.ul.com/services/energy-storage-system-testing-and-certification
9. Claim-to-source audit
| Claim in the text | Type | Reference |
|---|---|---|
| Founded 1906, nonprofit membership organization, 30,000 experts, around 10,000 standards, four conformity assessment systems | Sourced | Reference 1 https://www.iec.ch/what-we-do |
| Under the WTO TBT Agreement, international standards become the basis for national standards, technical regulations and certification | Sourced | Reference 2 https://www.iec.ch/what-we-do/iec-and-global-trade |
| 92 National Committees (64 full, 28 associate); individuals and companies cannot join; experts take part in a personal capacity; Japan's admission (1910) | Sourced | Reference 3 https://www.iec.ch/national-committees |
| Standards are voluntary, consensus-based international standards; 118 technical committees, 105 subcommittees, 881 working groups | Sourced | Reference 4 https://www.iec.ch/technical-committees-and-subcommittees |
| Headquarters in Geneva | Sourced | Reference 5 https://www.iec.ch/contact |
| 157 Secretariat staff (147.2 FTE), 167 countries (89 members, 78 affiliates), operational income of CHF 36.11 million and dues of CHF 13.24 million, 12,450 standards, 2.5 to 3 years to publication, the agreement with ISO, funding sources | Sourced | Reference 6 https://www.iecex.com/dmsdocument/4942/ |
| Scope of TC 21, cooperating committees, secretariat France | Sourced | Reference 7 https://www.iec.ch/dyn/www/f?p=103:7:::::FSP_ORG_ID:1290 |
| TC 21 publications (IEC 61427, 62485-5, 62660) | Sourced | Reference 8 https://www.iec.ch/dyn/www/f?p=103:22:0::::FSP_ORG_ID:1290 |
| TC 21 projects (TR 62660-5, sodium-ion, flow batteries) and forecast dates | Sourced | Reference 9 https://www.iec.ch/dyn/www/f?p=103:23:::::FSP_ORG_ID:1290 |
| Scope and publications of SC 21A (IEC 62619, 63056), its projects, secretariat France | Sourced | Reference 10 https://www.iec.ch/dyn/www/f?p=103:22:0::::FSP_ORG_ID:1410 |
| Scope of TC 120 and secretariat Japan | Sourced | Reference 11 https://www.iec.ch/dyn/www/f?p=103:7:::::FSP_ORG_ID:9463 |
| Titles, editions and dates of the IEC 62933 series; 20 publications | Sourced | Reference 12 https://www.iec.ch/dyn/www/f?p=103:22:0::::FSP_ORG_ID:9463 |
| TC 120 projects and forecast dates | Sourced | Reference 13 https://www.iec.ch/dyn/www/f?p=103:23:::::FSP_ORG_ID:9463 |
| Scope, price and stability date of IEC 62619:2022 | Sourced | Reference 14 https://webstore.iec.ch/en/publication/64073 |
| Scope, maximum DC voltage and stability date of IEC 63056:2020 | Sourced | Reference 15 https://webstore.iec.ch/en/publication/29224 |
| Scope, second edition, price and stability date of IEC 62933-5-2:2025 | Sourced | Reference 16 https://webstore.iec.ch/en/publication/68297 |
| IEC 62619:2022 is in IECEE category BATT | Sourced | Reference 17 https://www.iecee.org/certification/iec-standards/iec-626192022 |
| Purpose of JIS C 4441, the FDMA's proposed relaxation naming IEC 62933-5-2, and JIS C 4412 | Sourced | Reference 18 https://www.fdma.go.jp/singi_kento/kento/items/post-116/01/shiryou3-1.pdf |
| UL Solutions advertises testing to IEC 62933-5-2 and similar standards | Sourced | Reference 19 https://www.ul.com/services/energy-storage-system-testing-and-certification |
| The four-type grouping of institutions, the flow in Fig. 2 and the materials engineer's reading | Our calculation | This article's own synthesis |
| Whether IEC 62619 will be revised, whether forecast dates are met, whether US codes designate IEC standards, how many people and which companies sit on the storage committees, and the content of the standards themselves | Not yet confirmed | Not stated in References 1-19, or could not be confirmed. This article does not estimate them |
| The two items in the Outlook marked as inferences (new chemistries enter as guides first; a possible review of JIS C 4441) | Inference | This article's reading of References 9, 13, 16 and 18 |
Last updated October 2026 / Troy Technical
Figures and work programmes come from the IEC website (as viewed in October 2026), the IEC's Performance Report to the General Assembly, IECEE pages and a document of Japan's Fire and Disaster Management Agency. The IEC's forecast publication dates are updated from time to time. Items marked "Inference" are this article's reading of the primary sources. The standards themselves were not consulted.