If you are an EPC contractor, an installer moving into storage, a C&I business, or a distributor importing a containerised BESS from 100 kWh — or a project at 215 kWh / 1 MWh scale — the short answer is this: the system needs separate certificates across four levels — transport, cell/battery, system, and market access — and a certified cell does not make the system certified. The pain we see every week: an uncertified system means a container stuck at the border as undocumented dangerous goods, or an install that is uninsurable and cannot be commissioned. Below is exactly what each certificate proves and how to check the paperwork is real.
The most common mistake: transport cert ≠ product-safety cert
Suppliers routinely conflate two different things. UN 38.3 is transport safety only: it proves a battery can be shipped by air or sea. It says nothing about whether the system is safe to operate on site for years. When a supplier answers "what certificates?" with only UN 38.3, that is a red flag, not a complete package. Likewise, a datasheet carrying CE/UL/IEC logos means nothing without the actual test reports tied to the exact model and BOM.
Here it is, level by level.
Transport: UN 38.3 + test summary + SDS
This is what physically lets the container move. Lithium-ion batteries are Class 9 dangerous goods, and the carrier will demand documents.
- UN 38.3 (section 38.3 of the UN Manual of Tests and Criteria) — eight tests: T1 altitude simulation, T2 thermal cycling (−40 to +72 °C), T3 vibration, T4 shock, T5 external short circuit, T6 impact/crush, T7 overcharge, T8 forced discharge. It proves the cell/battery is safe in transport.
- Test Summary (UN 38.3 report) — since 1 January 2020 it is mandatory to make available to everyone in the supply chain (carrier, forwarder, customs). No summary, and transport is refused. Any design change (a new BMS revision, a different cell count) requires fresh testing.
- SDS/MSDS (safety data sheet) — needed to declare the dangerous goods and clear customs.
- Correct UN numbers: UN 3480 (batteries shipped alone), UN 3481 (batteries in or packed with equipment), UN 3536 (batteries installed in a cargo transport unit — typical for a containerised BESS).
How this plays out in practice, and where shipments break, is covered in our guide on shipping lithium batteries as dangerous goods.
Cell and battery safety: IEC 62619, IEC 62620
This is product safety, not transport. It checks whether a cell will go into thermal runaway under normal operation.
- IEC 62619 — safety of industrial secondary lithium-ion cells and batteries: protection against overcharge, over-discharge, external short circuit, vibration, temperature extremes, forced discharge, and thermal-runaway propagation. This is the baseline safety cert for C&I / industrial BESS.
- IEC 62620 — performance and marking requirements for industrial lithium-ion cells and batteries (capacity, cycle life, operating regimes). It complements 62619 on the specifications side.
- For LiFePO₄ cells, grade quality (grade A vs B / re-sorted) is invisible on a datasheet — it has to be verified physically. Detail in our post on sourcing LiFePO₄ cells from China.
System safety and install: IEC 62933-5-2, UL 9540, UL 9540A, NFPA 855
A cell can be certified while the assembled system is not. This is a separate level that most sellers skip.
- IEC 62933-5-2 — safety requirements for grid-integrated electrochemical energy storage (EES) systems: the system as a whole, not individual components. Part of the IEC 62933 family.
- UL 9540 — certification of the complete system (battery + PCS + controls + interconnects) as an integrated product. It is not a single-module test.
- UL 9540A — this is a test method for thermal-runaway fire propagation, not a certification. It generates the data used to design fire separation distances and suppression. A proper report covers three levels: cell, module, and unit. A supplier showing only a cell-level result is giving you an incomplete picture.
- NFPA 855 — the installation standard (spacing, ventilation, fire protection). Nominally "voluntary," but in practice required by local building codes and insurers to commission the system.
A certified cell does not make the system certified — these are four distinct levels, and an install becomes insurable only when every one of them is closed.
Power conversion (PCS): IEC 62477, IEC 62109
The PCS — the interface between battery and grid — carries its own safety certs.
- IEC 62477-1 — safety of power electronic converter systems (PECS): inverters, PCS, chargers, up to 1000 V AC / 1500 V DC.
- IEC 62109-1/-2 — safety of converters in photovoltaic systems; applied to hybrid ESS inverters. For solar-plus-storage sites, the PCS is often assessed against this family alongside IEC 62933.
Market access: CE / EU and regional requirements
This is permission to sell and import into a specific market — separate from product safety.
- CE / EU Declaration of Conformity — mandatory for the EU market; it rests on the relevant IEC/EN standards (LVD, EMC).
- Regional schemes — most markets in MENA, Africa and Asia have their own conformity route (national approval, type registration, or an equivalent). Confirm the applicable scheme for your destination before you ship.
- Ukraine (one example) — as of 2026, imports of critical energy equipment, including lithium-ion storage under HS 8507 60, are exempt from VAT and duty until 1 January 2029; the exemption excludes storage under 300 W (not relevant to containerised BESS). See our breakdown of the Ukraine solar VAT and duty exemption. This is a tax relief, not a substitute for safety certification — you need both. Verify current rules at time of import.
How to verify a certificate is genuine
A logo on a datasheet is not proof. The minimum check before you place a deposit:
- Confirm the certificate is issued to the exact model and BOM, not to a "similar" series or a different SKU.
- Find the certificate in the certification body's database (UL Product iQ, the IEC/CB certificate body's registry) rather than trusting a PDF from the seller.
- Demand the full test reports (the UN 38.3 Test Summary, the UL 9540A report across all levels), not a single stamped page.
- Check date and revision: a BMS change or a different cell count voids the old UN 38.3.
A datasheet listing certs is worth nothing without the reports behind it. This is why sourcing is a full cycle, not "just logistics": verifying the factory before the deal and an independent quality inspection before shipment are precisely where a swapped cell or a forged certificate is caught.
Sources and references
- UN 38.3 and the UN Manual of Tests and Criteria — unece.org.
- Thermal-runaway fire test method — UL 9540A (ul.com).
- Cell and system safety standards — IEC 62619 / 62933 (iec.ch).
Silk Way Sourcing verifies certificates against the issuing bodies, cross-checks reports against the real model and BOM, and sources compliant BESS direct from the factory — see our BESS sourcing page.
Send us your BESS model and datasheet — we will verify the certificates are complete and genuine and source a compliant system matched to your site, direct from the factory. Reach us at contact@silkwaysourcing.com or WhatsApp +380 97 883 4765.
