Battery certification, explained
Certification rarely fails on the test. It fails because the report describes a build different from the one being shipped — a cell substitution, a BMS change, a modified enclosure — and nobody notices until customs or an audit asks.
UN38.3 — transport, required everywhere
UN38.3 is the UN test standard for transporting lithium batteries. Without it, the pack cannot legally be shipped by air, sea or road as declared dangerous goods.
It covers altitude simulation, thermal cycling, vibration, shock, external short circuit, impact, overcharge and forced discharge on the cell and battery level, and it is accompanied by a test summary that carriers and customs require.
Unlike the other standards below, UN38.3 does not relate to product safety in use. It is a transport requirement, and it applies to every lithium battery sold internationally.
IEC 62619 — industrial and storage
IEC 62619 is the standard most relevant to stationary storage and industrial applications in markets that follow IEC. It covers safety requirements and test methods for secondary lithium cells and batteries used in industrial applications.
If you are selling a battery pack for energy storage, industrial machinery or telecom backup into most of Europe, Asia and Australia, this is the standard your customer or their certification body will ask for.
IEC 62133-2 — portable products
IEC 62133-2 covers secondary lithium cells and batteries for portable applications. It is the standard for consumer-facing portable products — power stations, hand tools, portable electronics — and it is what consumer safety regulators commonly reference.
UL 1973 and UL 2054 — North America
UL 1973 covers batteries for use in stationary, vehicle auxiliary power and light electric rail applications. It is the standard for energy storage in North America, and some markets additionally require UL 9540 at the system level, which covers the battery together with its inverter or PCS as an assembly.
UL 2054 covers household and commercial battery packs, and is more relevant to portable and consumer products.
A common and expensive misunderstanding: UL 1973 certification of the cells is not UL 1973 certification of the pack. Buyers should check that the report names the finished product configuration, not a component.
CE marking — the EU
CE marking is a declaration that the product meets applicable EU directives — commonly EMC and Low Voltage, and battery-specific requirements. It is supported by a technical file rather than a single test report, which means the manufacturer has to hold the design documentation, the risk assessment and the test evidence.
RoHS and REACH are separate substance restrictions that are normally addressed in the same technical file.
Why the tested build must match the shipped build
A certification report describes a specific configuration: specific cells, a specific BMS, a specific enclosure and a specific firmware behaviour. Change any of those and the report no longer describes the product.
The changes that most often invalidate a report, usually without anyone intending it:
- A cell substitution to improve lead time or reduce cost
- A BMS change to fix an inverter integration issue
- An enclosure modification requested by a customer
- A firmware change that alters protection thresholds
Any of these can leave a product technically uncertified, which is discovered at customs, at a customer audit or in an incident investigation — the worst possible moment.
The practical rule: certify the production build, and ask your supplier in writing what changes would require a re-test before you make them.